/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.widget;

import android.annotation.IntDef;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.View;
import android.view.ViewDebug;
import android.view.ViewGroup;
import android.view.ViewHierarchyEncoder;
import android.widget.RemoteViews.RemoteView;

import com.android.internal.R;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;


A layout that arranges other views either horizontally in a single column
or vertically in a single row.
The following snippet shows how to include a linear layout in your layout XML file:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:paddingLeft="16dp"
  android:paddingRight="16dp"
  android:orientation="horizontal"
  android:gravity="center">
  <!-- Include other widget or layout tags here. These are considered
          "child views" or "children" of the linear layout -->
</LinearLayout>
Set android:orientation to specify whether child views are displayed in a row or column.
To control how linear layout aligns all the views it contains, set a value for android:gravity. For example, the snippet above sets android:gravity to "center". The value you set affects both horizontal and vertical alignment of all child views within the single row or column.
You can set android:layout_weight on individual child views to specify how linear layout divides remaining space amongst the views it contains. See the Linear Layout
guide for an example.
See LinearLayout.LayoutParams to learn about other attributes you can set on a child view to affect its position and size in the containing linear layout.
@attr
ref android.R.styleable#LinearLayout_baselineAligned
@attr
ref android.R.styleable#LinearLayout_baselineAlignedChildIndex
@attr
ref android.R.styleable#LinearLayout_gravity
@attr
ref android.R.styleable#LinearLayout_measureWithLargestChild
@attr
ref android.R.styleable#LinearLayout_orientation
@attr
ref android.R.styleable#LinearLayout_weightSum/**
 * A layout that arranges other views either horizontally in a single column
 * or vertically in a single row.
 *
 * <p>The following snippet shows how to include a linear layout in your layout XML file:</p>
 *
 * <pre>&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 *   android:layout_width="match_parent"
 *   android:layout_height="match_parent"
 *   android:paddingLeft="16dp"
 *   android:paddingRight="16dp"
 *   android:orientation="horizontal"
 *   android:gravity="center"&gt;
 *
 *   &lt;!-- Include other widget or layout tags here. These are considered
 *           "child views" or "children" of the linear layout --&gt;
 *
 * &lt;/LinearLayout&gt;</pre>
 *
 * <p>Set {@link android.R.styleable#LinearLayout_orientation android:orientation} to specify
 * whether child views are displayed in a row or column.</p>
 *
 * <p>To control how linear layout aligns all the views it contains, set a value for
 * {@link android.R.styleable#LinearLayout_gravity android:gravity}.  For example, the
 * snippet above sets android:gravity to "center".  The value you set affects
 * both horizontal and vertical alignment of all child views within the single row or column.</p>
 *
 * <p>You can set
 * {@link android.R.styleable#LinearLayout_Layout_layout_weight android:layout_weight}
 * on individual child views to specify how linear layout divides remaining space amongst
 * the views it contains. See the
 * <a href="https://developer.android.com/guide/topics/ui/layout/linear.html">Linear Layout</a>
 * guide for an example.</p>
 *
 * <p>See
 * {@link android.widget.LinearLayout.LayoutParams LinearLayout.LayoutParams}
 * to learn about other attributes you can set on a child view to affect its
 * position and size in the containing linear layout.</p>
 *
 * @attr ref android.R.styleable#LinearLayout_baselineAligned
 * @attr ref android.R.styleable#LinearLayout_baselineAlignedChildIndex
 * @attr ref android.R.styleable#LinearLayout_gravity
 * @attr ref android.R.styleable#LinearLayout_measureWithLargestChild
 * @attr ref android.R.styleable#LinearLayout_orientation
 * @attr ref android.R.styleable#LinearLayout_weightSum
 */
@RemoteView
public class LinearLayout extends ViewGroup {
    
@hide
/** @hide */
    @IntDef({HORIZONTAL, VERTICAL})
    @Retention(RetentionPolicy.SOURCE)
    public @interface OrientationMode {}

    public static final int HORIZONTAL = 0;
    public static final int VERTICAL = 1;

    
@hide
/** @hide */
    @IntDef(flag = true, prefix = { "SHOW_DIVIDER_" }, value = {
            SHOW_DIVIDER_NONE,
            SHOW_DIVIDER_BEGINNING,
            SHOW_DIVIDER_MIDDLE,
            SHOW_DIVIDER_END
    })
    @Retention(RetentionPolicy.SOURCE)
    public @interface DividerMode {}

    
Don't show any dividers.
/**
     * Don't show any dividers.
     */
    public static final int SHOW_DIVIDER_NONE = 0;
    
Show a divider at the beginning of the group.
/**
     * Show a divider at the beginning of the group.
     */
    public static final int SHOW_DIVIDER_BEGINNING = 1;
    
Show dividers between each item in the group.
/**
     * Show dividers between each item in the group.
     */
    public static final int SHOW_DIVIDER_MIDDLE = 2;
    
Show a divider at the end of the group.
/**
     * Show a divider at the end of the group.
     */
    public static final int SHOW_DIVIDER_END = 4;

    
Compatibility check. Old versions of the platform would give different
results from measurement passes using EXACTLY and non-EXACTLY modes,
even when the resulting size was the same.
/**
     * Compatibility check. Old versions of the platform would give different
     * results from measurement passes using EXACTLY and non-EXACTLY modes,
     * even when the resulting size was the same.
     */
    private final boolean mAllowInconsistentMeasurement;

    
Whether the children of this layout are baseline aligned. Only applicable if mOrientation is horizontal. /**
     * Whether the children of this layout are baseline aligned.  Only applicable
     * if {@link #mOrientation} is horizontal.
     */
    @ViewDebug.ExportedProperty(category = "layout")
    private boolean mBaselineAligned = true;

    
If this layout is part of another layout that is baseline aligned, use the child at this index as the baseline. Note: this is orthogonal to mBaselineAligned, which is concerned with whether the children of this layout are baseline aligned. /**
     * If this layout is part of another layout that is baseline aligned,
     * use the child at this index as the baseline.
     *
     * Note: this is orthogonal to {@link #mBaselineAligned}, which is concerned
     * with whether the children of this layout are baseline aligned.
     */
    @ViewDebug.ExportedProperty(category = "layout")
    private int mBaselineAlignedChildIndex = -1;

    
The additional offset to the child's baseline.
We'll calculate the baseline of this layout as we measure vertically; for
horizontal linear layouts, the offset of 0 is appropriate.
/**
     * The additional offset to the child's baseline.
     * We'll calculate the baseline of this layout as we measure vertically; for
     * horizontal linear layouts, the offset of 0 is appropriate.
     */
    @ViewDebug.ExportedProperty(category = "measurement")
    private int mBaselineChildTop = 0;

    @ViewDebug.ExportedProperty(category = "measurement")
    private int mOrientation;

    @ViewDebug.ExportedProperty(category = "measurement", flagMapping = {
            @ViewDebug.FlagToString(mask = -1,
                equals = -1, name = "NONE"),
            @ViewDebug.FlagToString(mask = Gravity.NO_GRAVITY,
                equals = Gravity.NO_GRAVITY,name = "NONE"),
            @ViewDebug.FlagToString(mask = Gravity.TOP,
                equals = Gravity.TOP, name = "TOP"),
            @ViewDebug.FlagToString(mask = Gravity.BOTTOM,
                equals = Gravity.BOTTOM, name = "BOTTOM"),
            @ViewDebug.FlagToString(mask = Gravity.LEFT,
                equals = Gravity.LEFT, name = "LEFT"),
            @ViewDebug.FlagToString(mask = Gravity.RIGHT,
                equals = Gravity.RIGHT, name = "RIGHT"),
            @ViewDebug.FlagToString(mask = Gravity.START,
                equals = Gravity.START, name = "START"),
            @ViewDebug.FlagToString(mask = Gravity.END,
                equals = Gravity.END, name = "END"),
            @ViewDebug.FlagToString(mask = Gravity.CENTER_VERTICAL,
                equals = Gravity.CENTER_VERTICAL, name = "CENTER_VERTICAL"),
            @ViewDebug.FlagToString(mask = Gravity.FILL_VERTICAL,
                equals = Gravity.FILL_VERTICAL, name = "FILL_VERTICAL"),
            @ViewDebug.FlagToString(mask = Gravity.CENTER_HORIZONTAL,
                equals = Gravity.CENTER_HORIZONTAL, name = "CENTER_HORIZONTAL"),
            @ViewDebug.FlagToString(mask = Gravity.FILL_HORIZONTAL,
                equals = Gravity.FILL_HORIZONTAL, name = "FILL_HORIZONTAL"),
            @ViewDebug.FlagToString(mask = Gravity.CENTER,
                equals = Gravity.CENTER, name = "CENTER"),
            @ViewDebug.FlagToString(mask = Gravity.FILL,
                equals = Gravity.FILL, name = "FILL"),
            @ViewDebug.FlagToString(mask = Gravity.RELATIVE_LAYOUT_DIRECTION,
                equals = Gravity.RELATIVE_LAYOUT_DIRECTION, name = "RELATIVE")
        }, formatToHexString = true)
    private int mGravity = Gravity.START | Gravity.TOP;

    @ViewDebug.ExportedProperty(category = "measurement")
    private int mTotalLength;

    @ViewDebug.ExportedProperty(category = "layout")
    private float mWeightSum;

    @ViewDebug.ExportedProperty(category = "layout")
    private boolean mUseLargestChild;

    private int[] mMaxAscent;
    private int[] mMaxDescent;

    private static final int VERTICAL_GRAVITY_COUNT = 4;

    private static final int INDEX_CENTER_VERTICAL = 0;
    private static final int INDEX_TOP = 1;
    private static final int INDEX_BOTTOM = 2;
    private static final int INDEX_FILL = 3;

    private Drawable mDivider;
    private int mDividerWidth;
    private int mDividerHeight;
    private int mShowDividers;
    private int mDividerPadding;

    private int mLayoutDirection = View.LAYOUT_DIRECTION_UNDEFINED;

    
Signals that compatibility booleans have been initialized according to
target SDK versions.
/**
     * Signals that compatibility booleans have been initialized according to
     * target SDK versions.
     */
    private static boolean sCompatibilityDone = false;

    
Behavior change in P; always remeasure weighted children, regardless of excess space.
/**
     * Behavior change in P; always remeasure weighted children, regardless of excess space.
     */
    private static boolean sRemeasureWeightedChildren = true;

    public LinearLayout(Context context) {
        this(context, null);
    }

    public LinearLayout(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public LinearLayout(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

    public LinearLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);

        if (!sCompatibilityDone && context != null) {
            final int targetSdkVersion = context.getApplicationInfo().targetSdkVersion;

            // Older apps only remeasure non-zero children
            sRemeasureWeightedChildren = targetSdkVersion >= Build.VERSION_CODES.P;

            sCompatibilityDone = true;
        }

        final TypedArray a = context.obtainStyledAttributes(
                attrs, com.android.internal.R.styleable.LinearLayout, defStyleAttr, defStyleRes);

        int index = a.getInt(com.android.internal.R.styleable.LinearLayout_orientation, -1);
        if (index >= 0) {
            setOrientation(index);
        }

        index = a.getInt(com.android.internal.R.styleable.LinearLayout_gravity, -1);
        if (index >= 0) {
            setGravity(index);
        }

        boolean baselineAligned = a.getBoolean(R.styleable.LinearLayout_baselineAligned, true);
        if (!baselineAligned) {
            setBaselineAligned(baselineAligned);
        }

        mWeightSum = a.getFloat(R.styleable.LinearLayout_weightSum, -1.0f);

        mBaselineAlignedChildIndex =
                a.getInt(com.android.internal.R.styleable.LinearLayout_baselineAlignedChildIndex, -1);

        mUseLargestChild = a.getBoolean(R.styleable.LinearLayout_measureWithLargestChild, false);

        mShowDividers = a.getInt(R.styleable.LinearLayout_showDividers, SHOW_DIVIDER_NONE);
        mDividerPadding = a.getDimensionPixelSize(R.styleable.LinearLayout_dividerPadding, 0);
        setDividerDrawable(a.getDrawable(R.styleable.LinearLayout_divider));

        final int version = context.getApplicationInfo().targetSdkVersion;
        mAllowInconsistentMeasurement = version <= Build.VERSION_CODES.M;

        a.recycle();
    }

    
Returns true if this layout is currently configured to show at least one
divider.
/**
     * Returns <code>true</code> if this layout is currently configured to show at least one
     * divider.
     */
    private boolean isShowingDividers() {
        return (mShowDividers != SHOW_DIVIDER_NONE) && (mDivider != null);
    }

    
Set how dividers should be shown between items in this layout
Params:
showDividers – One or more of SHOW_DIVIDER_BEGINNING, SHOW_DIVIDER_MIDDLE, or SHOW_DIVIDER_END to show dividers, or SHOW_DIVIDER_NONE to show no dividers./**
     * Set how dividers should be shown between items in this layout
     *
     * @param showDividers One or more of {@link #SHOW_DIVIDER_BEGINNING},
     *                     {@link #SHOW_DIVIDER_MIDDLE}, or {@link #SHOW_DIVIDER_END}
     *                     to show dividers, or {@link #SHOW_DIVIDER_NONE} to show no dividers.
     */
    public void setShowDividers(@DividerMode int showDividers) {
        if (showDividers == mShowDividers) {
            return;
        }
        mShowDividers = showDividers;

        setWillNotDraw(!isShowingDividers());
        requestLayout();
    }

    @Override
    public boolean shouldDelayChildPressedState() {
        return false;
    }

    
See Also:
setShowDividers(int)
Returns:
A flag set indicating how dividers should be shown around items./**
     * @return A flag set indicating how dividers should be shown around items.
     * @see #setShowDividers(int)
     */
    @DividerMode
    public int getShowDividers() {
        return mShowDividers;
    }

    
See Also:
setDividerDrawable(Drawable)
Returns:
the divider Drawable that will divide each item.
@attr
ref android.R.styleable#LinearLayout_divider/**
     * @return the divider Drawable that will divide each item.
     *
     * @see #setDividerDrawable(Drawable)
     *
     * @attr ref android.R.styleable#LinearLayout_divider
     */
    public Drawable getDividerDrawable() {
        return mDivider;
    }

    
Set a drawable to be used as a divider between items.
Params:
divider – Drawable that will divide each item.
See Also:
setShowDividers(int)
@attr
ref android.R.styleable#LinearLayout_divider/**
     * Set a drawable to be used as a divider between items.
     *
     * @param divider Drawable that will divide each item.
     *
     * @see #setShowDividers(int)
     *
     * @attr ref android.R.styleable#LinearLayout_divider
     */
    public void setDividerDrawable(Drawable divider) {
        if (divider == mDivider) {
            return;
        }
        mDivider = divider;
        if (divider != null) {
            mDividerWidth = divider.getIntrinsicWidth();
            mDividerHeight = divider.getIntrinsicHeight();
        } else {
            mDividerWidth = 0;
            mDividerHeight = 0;
        }

        setWillNotDraw(!isShowingDividers());
        requestLayout();
    }

    
Set padding displayed on both ends of dividers. For a vertical layout, the padding is applied
to left and right end of dividers. For a horizontal layout, the padding is applied to top and
bottom end of dividers.
Params:
padding – Padding value in pixels that will be applied to each end
See Also:
setShowDividers(int)
setDividerDrawable(Drawable)
getDividerPadding()/**
     * Set padding displayed on both ends of dividers. For a vertical layout, the padding is applied
     * to left and right end of dividers. For a horizontal layout, the padding is applied to top and
     * bottom end of dividers.
     *
     * @param padding Padding value in pixels that will be applied to each end
     *
     * @see #setShowDividers(int)
     * @see #setDividerDrawable(Drawable)
     * @see #getDividerPadding()
     */
    public void setDividerPadding(int padding) {
        if (padding == mDividerPadding) {
            return;
        }
        mDividerPadding = padding;

        if (isShowingDividers()) {
            requestLayout();
            invalidate();
        }
    }

    
Get the padding size used to inset dividers in pixels
See Also:
setShowDividers(int)
setDividerDrawable(Drawable)
setDividerPadding(int)/**
     * Get the padding size used to inset dividers in pixels
     *
     * @see #setShowDividers(int)
     * @see #setDividerDrawable(Drawable)
     * @see #setDividerPadding(int)
     */
    public int getDividerPadding() {
        return mDividerPadding;
    }

    
Get the width of the current divider drawable.
@hide
Used internally by framework./**
     * Get the width of the current divider drawable.
     *
     * @hide Used internally by framework.
     */
    public int getDividerWidth() {
        return mDividerWidth;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (mDivider == null) {
            return;
        }

        if (mOrientation == VERTICAL) {
            drawDividersVertical(canvas);
        } else {
            drawDividersHorizontal(canvas);
        }
    }

    void drawDividersVertical(Canvas canvas) {
        final int count = getVirtualChildCount();
        for (int i = 0; i < count; i++) {
            final View child = getVirtualChildAt(i);
            if (child != null && child.getVisibility() != GONE) {
                if (hasDividerBeforeChildAt(i)) {
                    final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                    final int top = child.getTop() - lp.topMargin - mDividerHeight;
                    drawHorizontalDivider(canvas, top);
                }
            }
        }

        if (hasDividerBeforeChildAt(count)) {
            final View child = getLastNonGoneChild();
            int bottom = 0;
            if (child == null) {
                bottom = getHeight() - getPaddingBottom() - mDividerHeight;
            } else {
                final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                bottom = child.getBottom() + lp.bottomMargin;
            }
            drawHorizontalDivider(canvas, bottom);
        }
    }

    
Finds the last child that is not gone. The last child will be used as the reference for
where the end divider should be drawn.
/**
     * Finds the last child that is not gone. The last child will be used as the reference for
     * where the end divider should be drawn.
     */
    private View getLastNonGoneChild() {
        for (int i = getVirtualChildCount() - 1; i >= 0; i--) {
            final View child = getVirtualChildAt(i);
            if (child != null && child.getVisibility() != GONE) {
                return child;
            }
        }
        return null;
    }

    void drawDividersHorizontal(Canvas canvas) {
        final int count = getVirtualChildCount();
        final boolean isLayoutRtl = isLayoutRtl();
        for (int i = 0; i < count; i++) {
            final View child = getVirtualChildAt(i);
            if (child != null && child.getVisibility() != GONE) {
                if (hasDividerBeforeChildAt(i)) {
                    final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                    final int position;
                    if (isLayoutRtl) {
                        position = child.getRight() + lp.rightMargin;
                    } else {
                        position = child.getLeft() - lp.leftMargin - mDividerWidth;
                    }
                    drawVerticalDivider(canvas, position);
                }
            }
        }

        if (hasDividerBeforeChildAt(count)) {
            final View child = getLastNonGoneChild();
            int position;
            if (child == null) {
                if (isLayoutRtl) {
                    position = getPaddingLeft();
                } else {
                    position = getWidth() - getPaddingRight() - mDividerWidth;
                }
            } else {
                final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                if (isLayoutRtl) {
                    position = child.getLeft() - lp.leftMargin - mDividerWidth;
                } else {
                    position = child.getRight() + lp.rightMargin;
                }
            }
            drawVerticalDivider(canvas, position);
        }
    }

    void drawHorizontalDivider(Canvas canvas, int top) {
        mDivider.setBounds(getPaddingLeft() + mDividerPadding, top,
                getWidth() - getPaddingRight() - mDividerPadding, top + mDividerHeight);
        mDivider.draw(canvas);
    }

    void drawVerticalDivider(Canvas canvas, int left) {
        mDivider.setBounds(left, getPaddingTop() + mDividerPadding,
                left + mDividerWidth, getHeight() - getPaddingBottom() - mDividerPadding);
        mDivider.draw(canvas);
    }

    
Indicates whether widgets contained within this layout are aligned
on their baseline or not.
Returns:
true when widgets are baseline-aligned, false otherwise/**
     * <p>Indicates whether widgets contained within this layout are aligned
     * on their baseline or not.</p>
     *
     * @return true when widgets are baseline-aligned, false otherwise
     */
    public boolean isBaselineAligned() {
        return mBaselineAligned;
    }

    
Defines whether widgets contained in this layout are
baseline-aligned or not.
Params:
baselineAligned – true to align widgets on their baseline,
        false otherwise
@attr
ref android.R.styleable#LinearLayout_baselineAligned/**
     * <p>Defines whether widgets contained in this layout are
     * baseline-aligned or not.</p>
     *
     * @param baselineAligned true to align widgets on their baseline,
     *         false otherwise
     *
     * @attr ref android.R.styleable#LinearLayout_baselineAligned
     */
    @android.view.RemotableViewMethod
    public void setBaselineAligned(boolean baselineAligned) {
        mBaselineAligned = baselineAligned;
    }

    
When true, all children with a weight will be considered having
the minimum size of the largest child. If false, all children are
measured normally.
Returns:
True to measure children with a weight using the minimum
        size of the largest child, false otherwise.
@attr
ref android.R.styleable#LinearLayout_measureWithLargestChild/**
     * When true, all children with a weight will be considered having
     * the minimum size of the largest child. If false, all children are
     * measured normally.
     *
     * @return True to measure children with a weight using the minimum
     *         size of the largest child, false otherwise.
     *
     * @attr ref android.R.styleable#LinearLayout_measureWithLargestChild
     */
    public boolean isMeasureWithLargestChildEnabled() {
        return mUseLargestChild;
    }

    
When set to true, all children with a weight will be considered having
the minimum size of the largest child. If false, all children are
measured normally.
Disabled by default.
Params:
enabled – True to measure children with a weight using the
       minimum size of the largest child, false otherwise.
@attr
ref android.R.styleable#LinearLayout_measureWithLargestChild/**
     * When set to true, all children with a weight will be considered having
     * the minimum size of the largest child. If false, all children are
     * measured normally.
     *
     * Disabled by default.
     *
     * @param enabled True to measure children with a weight using the
     *        minimum size of the largest child, false otherwise.
     *
     * @attr ref android.R.styleable#LinearLayout_measureWithLargestChild
     */
    @android.view.RemotableViewMethod
    public void setMeasureWithLargestChildEnabled(boolean enabled) {
        mUseLargestChild = enabled;
    }

    @Override
    public int getBaseline() {
        if (mBaselineAlignedChildIndex < 0) {
            return super.getBaseline();
        }

        if (getChildCount() <= mBaselineAlignedChildIndex) {
            throw new RuntimeException("mBaselineAlignedChildIndex of LinearLayout "
                    + "set to an index that is out of bounds.");
        }

        final View child = getChildAt(mBaselineAlignedChildIndex);
        final int childBaseline = child.getBaseline();

        if (childBaseline == -1) {
            if (mBaselineAlignedChildIndex == 0) {
                // this is just the default case, safe to return -1
                return -1;
            }
            // the user picked an index that points to something that doesn't
            // know how to calculate its baseline.
            throw new RuntimeException("mBaselineAlignedChildIndex of LinearLayout "
                    + "points to a View that doesn't know how to get its baseline.");
        }

        // TODO: This should try to take into account the virtual offsets
        // (See getNextLocationOffset and getLocationOffset)
        // We should add to childTop:
        // sum([getNextLocationOffset(getChildAt(i)) / i < mBaselineAlignedChildIndex])
        // and also add:
        // getLocationOffset(child)
        int childTop = mBaselineChildTop;

        if (mOrientation == VERTICAL) {
            final int majorGravity = mGravity & Gravity.VERTICAL_GRAVITY_MASK;
            if (majorGravity != Gravity.TOP) {
               switch (majorGravity) {
                   case Gravity.BOTTOM:
                       childTop = mBottom - mTop - mPaddingBottom - mTotalLength;
                       break;

                   case Gravity.CENTER_VERTICAL:
                       childTop += ((mBottom - mTop - mPaddingTop - mPaddingBottom) -
                               mTotalLength) / 2;
                       break;
               }
            }
        }

        LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) child.getLayoutParams();
        return childTop + lp.topMargin + childBaseline;
    }

    
Returns:
The index of the child that will be used if this layout is
  part of a larger layout that is baseline aligned, or -1 if none has
  been set./**
     * @return The index of the child that will be used if this layout is
     *   part of a larger layout that is baseline aligned, or -1 if none has
     *   been set.
     */
    public int getBaselineAlignedChildIndex() {
        return mBaselineAlignedChildIndex;
    }

    
Params:
i – The index of the child that will be used if this layout is
         part of a larger layout that is baseline aligned.
@attr
ref android.R.styleable#LinearLayout_baselineAlignedChildIndex/**
     * @param i The index of the child that will be used if this layout is
     *          part of a larger layout that is baseline aligned.
     *
     * @attr ref android.R.styleable#LinearLayout_baselineAlignedChildIndex
     */
    @android.view.RemotableViewMethod
    public void setBaselineAlignedChildIndex(int i) {
        if ((i < 0) || (i >= getChildCount())) {
            throw new IllegalArgumentException("base aligned child index out "
                    + "of range (0, " + getChildCount() + ")");
        }
        mBaselineAlignedChildIndex = i;
    }

    
Returns the view at the specified index. This method can be overridden to take into account virtual children. Refer to TableLayout and TableRow for an example.
Params:
index – the child's index
Returns:
the child at the specified index, may be null/**
     * <p>Returns the view at the specified index. This method can be overridden
     * to take into account virtual children. Refer to
     * {@link android.widget.TableLayout} and {@link android.widget.TableRow}
     * for an example.</p>
     *
     * @param index the child's index
     * @return the child at the specified index, may be {@code null}
     */
    @Nullable
    View getVirtualChildAt(int index) {
        return getChildAt(index);
    }

    
Returns the virtual number of children. This number might be different than the actual number of children if the layout can hold virtual children. Refer to TableLayout and TableRow for an example.
Returns:
the virtual number of children/**
     * <p>Returns the virtual number of children. This number might be different
     * than the actual number of children if the layout can hold virtual
     * children. Refer to
     * {@link android.widget.TableLayout} and {@link android.widget.TableRow}
     * for an example.</p>
     *
     * @return the virtual number of children
     */
    int getVirtualChildCount() {
        return getChildCount();
    }

    
Returns the desired weights sum.
Returns:
A number greater than 0.0f if the weight sum is defined, or
        a number lower than or equals to 0.0f if not weight sum is
        to be used./**
     * Returns the desired weights sum.
     *
     * @return A number greater than 0.0f if the weight sum is defined, or
     *         a number lower than or equals to 0.0f if not weight sum is
     *         to be used.
     */
    public float getWeightSum() {
        return mWeightSum;
    }

    
Defines the desired weights sum. If unspecified the weights sum is computed
at layout time by adding the layout_weight of each child.
This can be used for instance to give a single child 50% of the total
available space by giving it a layout_weight of 0.5 and setting the
weightSum to 1.0.
Params:
weightSum – a number greater than 0.0f, or a number lower than or equals
       to 0.0f if the weight sum should be computed from the children's
       layout_weight/**
     * Defines the desired weights sum. If unspecified the weights sum is computed
     * at layout time by adding the layout_weight of each child.
     *
     * This can be used for instance to give a single child 50% of the total
     * available space by giving it a layout_weight of 0.5 and setting the
     * weightSum to 1.0.
     *
     * @param weightSum a number greater than 0.0f, or a number lower than or equals
     *        to 0.0f if the weight sum should be computed from the children's
     *        layout_weight
     */
    @android.view.RemotableViewMethod
    public void setWeightSum(float weightSum) {
        mWeightSum = Math.max(0.0f, weightSum);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        if (mOrientation == VERTICAL) {
            measureVertical(widthMeasureSpec, heightMeasureSpec);
        } else {
            measureHorizontal(widthMeasureSpec, heightMeasureSpec);
        }
    }

    
Determines where to position dividers between children.
Params:
childIndex – Index of child to check for preceding divider
Returns:
true if there should be a divider before the child at childIndex
@hide
Pending API consideration. Currently only used internally by the system./**
     * Determines where to position dividers between children.
     *
     * @param childIndex Index of child to check for preceding divider
     * @return true if there should be a divider before the child at childIndex
     * @hide Pending API consideration. Currently only used internally by the system.
     */
    protected boolean hasDividerBeforeChildAt(int childIndex) {
        if (childIndex == getVirtualChildCount()) {
            // Check whether the end divider should draw.
            return (mShowDividers & SHOW_DIVIDER_END) != 0;
        }
        boolean allViewsAreGoneBefore = allViewsAreGoneBefore(childIndex);
        if (allViewsAreGoneBefore) {
            // This is the first view that's not gone, check if beginning divider is enabled.
            return (mShowDividers & SHOW_DIVIDER_BEGINNING) != 0;
        } else {
            return (mShowDividers & SHOW_DIVIDER_MIDDLE) != 0;
        }
    }

    
Checks whether all (virtual) child views before the given index are gone.
/**
     * Checks whether all (virtual) child views before the given index are gone.
     */
    private boolean allViewsAreGoneBefore(int childIndex) {
        for (int i = childIndex - 1; i >= 0; i--) {
            final View child = getVirtualChildAt(i);
            if (child != null && child.getVisibility() != GONE) {
                return false;
            }
        }
        return true;
    }

    
Measures the children when the orientation of this LinearLayout is set to VERTICAL. 
Params:
widthMeasureSpec – Horizontal space requirements as imposed by the parent.
heightMeasureSpec – Vertical space requirements as imposed by the parent.
See Also:
getOrientation()
setOrientation(int)
onMeasure(int, int)/**
     * Measures the children when the orientation of this LinearLayout is set
     * to {@link #VERTICAL}.
     *
     * @param widthMeasureSpec Horizontal space requirements as imposed by the parent.
     * @param heightMeasureSpec Vertical space requirements as imposed by the parent.
     *
     * @see #getOrientation()
     * @see #setOrientation(int)
     * @see #onMeasure(int, int)
     */
    void measureVertical(int widthMeasureSpec, int heightMeasureSpec) {
        mTotalLength = 0;
        int maxWidth = 0;
        int childState = 0;
        int alternativeMaxWidth = 0;
        int weightedMaxWidth = 0;
        boolean allFillParent = true;
        float totalWeight = 0;

        final int count = getVirtualChildCount();

        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        final int heightMode = MeasureSpec.getMode(heightMeasureSpec);

        boolean matchWidth = false;
        boolean skippedMeasure = false;

        final int baselineChildIndex = mBaselineAlignedChildIndex;
        final boolean useLargestChild = mUseLargestChild;

        int largestChildHeight = Integer.MIN_VALUE;
        int consumedExcessSpace = 0;

        int nonSkippedChildCount = 0;

        // See how tall everyone is. Also remember max width.
        for (int i = 0; i < count; ++i) {
            final View child = getVirtualChildAt(i);
            if (child == null) {
                mTotalLength += measureNullChild(i);
                continue;
            }

            if (child.getVisibility() == View.GONE) {
               i += getChildrenSkipCount(child, i);
               continue;
            }

            nonSkippedChildCount++;
            if (hasDividerBeforeChildAt(i)) {
                mTotalLength += mDividerHeight;
            }

            final LayoutParams lp = (LayoutParams) child.getLayoutParams();

            totalWeight += lp.weight;

            final boolean useExcessSpace = lp.height == 0 && lp.weight > 0;
            if (heightMode == MeasureSpec.EXACTLY && useExcessSpace) {
                // Optimization: don't bother measuring children who are only
                // laid out using excess space. These views will get measured
                // later if we have space to distribute.
                final int totalLength = mTotalLength;
                mTotalLength = Math.max(totalLength, totalLength + lp.topMargin + lp.bottomMargin);
                skippedMeasure = true;
            } else {
                if (useExcessSpace) {
                    // The heightMode is either UNSPECIFIED or AT_MOST, and
                    // this child is only laid out using excess space. Measure
                    // using WRAP_CONTENT so that we can find out the view's
                    // optimal height. We'll restore the original height of 0
                    // after measurement.
                    lp.height = LayoutParams.WRAP_CONTENT;
                }

                // Determine how big this child would like to be. If this or
                // previous children have given a weight, then we allow it to
                // use all available space (and we will shrink things later
                // if needed).
                final int usedHeight = totalWeight == 0 ? mTotalLength : 0;
                measureChildBeforeLayout(child, i, widthMeasureSpec, 0,
                        heightMeasureSpec, usedHeight);

                final int childHeight = child.getMeasuredHeight();
                if (useExcessSpace) {
                    // Restore the original height and record how much space
                    // we've allocated to excess-only children so that we can
                    // match the behavior of EXACTLY measurement.
                    lp.height = 0;
                    consumedExcessSpace += childHeight;
                }

                final int totalLength = mTotalLength;
                mTotalLength = Math.max(totalLength, totalLength + childHeight + lp.topMargin +
                       lp.bottomMargin + getNextLocationOffset(child));

                if (useLargestChild) {
                    largestChildHeight = Math.max(childHeight, largestChildHeight);
                }
            }

            /**
             * If applicable, compute the additional offset to the child's baseline
             * we'll need later when asked {@link #getBaseline}.
             */
            if ((baselineChildIndex >= 0) && (baselineChildIndex == i + 1)) {
               mBaselineChildTop = mTotalLength;
            }

            // if we are trying to use a child index for our baseline, the above
            // book keeping only works if there are no children above it with
            // weight.  fail fast to aid the developer.
            if (i < baselineChildIndex && lp.weight > 0) {
                throw new RuntimeException("A child of LinearLayout with index "
                        + "less than mBaselineAlignedChildIndex has weight > 0, which "
                        + "won't work.  Either remove the weight, or don't set "
                        + "mBaselineAlignedChildIndex.");
            }

            boolean matchWidthLocally = false;
            if (widthMode != MeasureSpec.EXACTLY && lp.width == LayoutParams.MATCH_PARENT) {
                // The width of the linear layout will scale, and at least one
                // child said it wanted to match our width. Set a flag
                // indicating that we need to remeasure at least that view when
                // we know our width.
                matchWidth = true;
                matchWidthLocally = true;
            }

            final int margin = lp.leftMargin + lp.rightMargin;
            final int measuredWidth = child.getMeasuredWidth() + margin;
            maxWidth = Math.max(maxWidth, measuredWidth);
            childState = combineMeasuredStates(childState, child.getMeasuredState());

            allFillParent = allFillParent && lp.width == LayoutParams.MATCH_PARENT;
            if (lp.weight > 0) {
                /*
                 * Widths of weighted Views are bogus if we end up
                 * remeasuring, so keep them separate.
                 */
                weightedMaxWidth = Math.max(weightedMaxWidth,
                        matchWidthLocally ? margin : measuredWidth);
            } else {
                alternativeMaxWidth = Math.max(alternativeMaxWidth,
                        matchWidthLocally ? margin : measuredWidth);
            }

            i += getChildrenSkipCount(child, i);
        }

        if (nonSkippedChildCount > 0 && hasDividerBeforeChildAt(count)) {
            mTotalLength += mDividerHeight;
        }

        if (useLargestChild &&
                (heightMode == MeasureSpec.AT_MOST || heightMode == MeasureSpec.UNSPECIFIED)) {
            mTotalLength = 0;

            for (int i = 0; i < count; ++i) {
                final View child = getVirtualChildAt(i);
                if (child == null) {
                    mTotalLength += measureNullChild(i);
                    continue;
                }

                if (child.getVisibility() == GONE) {
                    i += getChildrenSkipCount(child, i);
                    continue;
                }

                final LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)
                        child.getLayoutParams();
                // Account for negative margins
                final int totalLength = mTotalLength;
                mTotalLength = Math.max(totalLength, totalLength + largestChildHeight +
                        lp.topMargin + lp.bottomMargin + getNextLocationOffset(child));
            }
        }

        // Add in our padding
        mTotalLength += mPaddingTop + mPaddingBottom;

        int heightSize = mTotalLength;

        // Check against our minimum height
        heightSize = Math.max(heightSize, getSuggestedMinimumHeight());

        // Reconcile our calculated size with the heightMeasureSpec
        int heightSizeAndState = resolveSizeAndState(heightSize, heightMeasureSpec, 0);
        heightSize = heightSizeAndState & MEASURED_SIZE_MASK;
        // Either expand children with weight to take up available space or
        // shrink them if they extend beyond our current bounds. If we skipped
        // measurement on any children, we need to measure them now.
        int remainingExcess = heightSize - mTotalLength
                + (mAllowInconsistentMeasurement ? 0 : consumedExcessSpace);
        if (skippedMeasure
                || ((sRemeasureWeightedChildren || remainingExcess != 0) && totalWeight > 0.0f)) {
            float remainingWeightSum = mWeightSum > 0.0f ? mWeightSum : totalWeight;

            mTotalLength = 0;

            for (int i = 0; i < count; ++i) {
                final View child = getVirtualChildAt(i);
                if (child == null || child.getVisibility() == View.GONE) {
                    continue;
                }

                final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                final float childWeight = lp.weight;
                if (childWeight > 0) {
                    final int share = (int) (childWeight * remainingExcess / remainingWeightSum);
                    remainingExcess -= share;
                    remainingWeightSum -= childWeight;

                    final int childHeight;
                    if (mUseLargestChild && heightMode != MeasureSpec.EXACTLY) {
                        childHeight = largestChildHeight;
                    } else if (lp.height == 0 && (!mAllowInconsistentMeasurement
                            || heightMode == MeasureSpec.EXACTLY)) {
                        // This child needs to be laid out from scratch using
                        // only its share of excess space.
                        childHeight = share;
                    } else {
                        // This child had some intrinsic height to which we
                        // need to add its share of excess space.
                        childHeight = child.getMeasuredHeight() + share;
                    }

                    final int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
                            Math.max(0, childHeight), MeasureSpec.EXACTLY);
                    final int childWidthMeasureSpec = getChildMeasureSpec(widthMeasureSpec,
                            mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin,
                            lp.width);
                    child.measure(childWidthMeasureSpec, childHeightMeasureSpec);

                    // Child may now not fit in vertical dimension.
                    childState = combineMeasuredStates(childState, child.getMeasuredState()
                            & (MEASURED_STATE_MASK>>MEASURED_HEIGHT_STATE_SHIFT));
                }

                final int margin =  lp.leftMargin + lp.rightMargin;
                final int measuredWidth = child.getMeasuredWidth() + margin;
                maxWidth = Math.max(maxWidth, measuredWidth);

                boolean matchWidthLocally = widthMode != MeasureSpec.EXACTLY &&
                        lp.width == LayoutParams.MATCH_PARENT;

                alternativeMaxWidth = Math.max(alternativeMaxWidth,
                        matchWidthLocally ? margin : measuredWidth);

                allFillParent = allFillParent && lp.width == LayoutParams.MATCH_PARENT;

                final int totalLength = mTotalLength;
                mTotalLength = Math.max(totalLength, totalLength + child.getMeasuredHeight() +
                        lp.topMargin + lp.bottomMargin + getNextLocationOffset(child));
            }

            // Add in our padding
            mTotalLength += mPaddingTop + mPaddingBottom;
            // TODO: Should we recompute the heightSpec based on the new total length?
        } else {
            alternativeMaxWidth = Math.max(alternativeMaxWidth,
                                           weightedMaxWidth);


            // We have no limit, so make all weighted views as tall as the largest child.
            // Children will have already been measured once.
            if (useLargestChild && heightMode != MeasureSpec.EXACTLY) {
                for (int i = 0; i < count; i++) {
                    final View child = getVirtualChildAt(i);
                    if (child == null || child.getVisibility() == View.GONE) {
                        continue;
                    }

                    final LinearLayout.LayoutParams lp =
                            (LinearLayout.LayoutParams) child.getLayoutParams();

                    float childExtra = lp.weight;
                    if (childExtra > 0) {
                        child.measure(
                                MeasureSpec.makeMeasureSpec(child.getMeasuredWidth(),
                                        MeasureSpec.EXACTLY),
                                MeasureSpec.makeMeasureSpec(largestChildHeight,
                                        MeasureSpec.EXACTLY));
                    }
                }
            }
        }

        if (!allFillParent && widthMode != MeasureSpec.EXACTLY) {
            maxWidth = alternativeMaxWidth;
        }

        maxWidth += mPaddingLeft + mPaddingRight;

        // Check against our minimum width
        maxWidth = Math.max(maxWidth, getSuggestedMinimumWidth());

        setMeasuredDimension(resolveSizeAndState(maxWidth, widthMeasureSpec, childState),
                heightSizeAndState);

        if (matchWidth) {
            forceUniformWidth(count, heightMeasureSpec);
        }
    }

    private void forceUniformWidth(int count, int heightMeasureSpec) {
        // Pretend that the linear layout has an exact size.
        int uniformMeasureSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth(),
                MeasureSpec.EXACTLY);
        for (int i = 0; i< count; ++i) {
           final View child = getVirtualChildAt(i);
           if (child != null && child.getVisibility() != GONE) {
               LinearLayout.LayoutParams lp = ((LinearLayout.LayoutParams)child.getLayoutParams());

               if (lp.width == LayoutParams.MATCH_PARENT) {
                   // Temporarily force children to reuse their old measured height
                   // FIXME: this may not be right for something like wrapping text?
                   int oldHeight = lp.height;
                   lp.height = child.getMeasuredHeight();

                   // Remeasue with new dimensions
                   measureChildWithMargins(child, uniformMeasureSpec, 0, heightMeasureSpec, 0);
                   lp.height = oldHeight;
               }
           }
        }
    }

    
Measures the children when the orientation of this LinearLayout is set to HORIZONTAL. 
Params:
widthMeasureSpec – Horizontal space requirements as imposed by the parent.
heightMeasureSpec – Vertical space requirements as imposed by the parent.
See Also:
getOrientation()
setOrientation(int)
onMeasure(int, int)/**
     * Measures the children when the orientation of this LinearLayout is set
     * to {@link #HORIZONTAL}.
     *
     * @param widthMeasureSpec Horizontal space requirements as imposed by the parent.
     * @param heightMeasureSpec Vertical space requirements as imposed by the parent.
     *
     * @see #getOrientation()
     * @see #setOrientation(int)
     * @see #onMeasure(int, int)
     */
    void measureHorizontal(int widthMeasureSpec, int heightMeasureSpec) {
        mTotalLength = 0;
        int maxHeight = 0;
        int childState = 0;
        int alternativeMaxHeight = 0;
        int weightedMaxHeight = 0;
        boolean allFillParent = true;
        float totalWeight = 0;

        final int count = getVirtualChildCount();

        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        final int heightMode = MeasureSpec.getMode(heightMeasureSpec);

        boolean matchHeight = false;
        boolean skippedMeasure = false;

        if (mMaxAscent == null || mMaxDescent == null) {
            mMaxAscent = new int[VERTICAL_GRAVITY_COUNT];
            mMaxDescent = new int[VERTICAL_GRAVITY_COUNT];
        }

        final int[] maxAscent = mMaxAscent;
        final int[] maxDescent = mMaxDescent;

        maxAscent[0] = maxAscent[1] = maxAscent[2] = maxAscent[3] = -1;
        maxDescent[0] = maxDescent[1] = maxDescent[2] = maxDescent[3] = -1;

        final boolean baselineAligned = mBaselineAligned;
        final boolean useLargestChild = mUseLargestChild;

        final boolean isExactly = widthMode == MeasureSpec.EXACTLY;

        int largestChildWidth = Integer.MIN_VALUE;
        int usedExcessSpace = 0;

        int nonSkippedChildCount = 0;

        // See how wide everyone is. Also remember max height.
        for (int i = 0; i < count; ++i) {
            final View child = getVirtualChildAt(i);
            if (child == null) {
                mTotalLength += measureNullChild(i);
                continue;
            }

            if (child.getVisibility() == GONE) {
                i += getChildrenSkipCount(child, i);
                continue;
            }

            nonSkippedChildCount++;
            if (hasDividerBeforeChildAt(i)) {
                mTotalLength += mDividerWidth;
            }

            final LayoutParams lp = (LayoutParams) child.getLayoutParams();

            totalWeight += lp.weight;

            final boolean useExcessSpace = lp.width == 0 && lp.weight > 0;
            if (widthMode == MeasureSpec.EXACTLY && useExcessSpace) {
                // Optimization: don't bother measuring children who are only
                // laid out using excess space. These views will get measured
                // later if we have space to distribute.
                if (isExactly) {
                    mTotalLength += lp.leftMargin + lp.rightMargin;
                } else {
                    final int totalLength = mTotalLength;
                    mTotalLength = Math.max(totalLength, totalLength +
                            lp.leftMargin + lp.rightMargin);
                }

                // Baseline alignment requires to measure widgets to obtain the
                // baseline offset (in particular for TextViews). The following
                // defeats the optimization mentioned above. Allow the child to
                // use as much space as it wants because we can shrink things
                // later (and re-measure).
                if (baselineAligned) {
                    final int freeWidthSpec = MeasureSpec.makeSafeMeasureSpec(
                            MeasureSpec.getSize(widthMeasureSpec), MeasureSpec.UNSPECIFIED);
                    final int freeHeightSpec = MeasureSpec.makeSafeMeasureSpec(
                            MeasureSpec.getSize(heightMeasureSpec), MeasureSpec.UNSPECIFIED);
                    child.measure(freeWidthSpec, freeHeightSpec);
                } else {
                    skippedMeasure = true;
                }
            } else {
                if (useExcessSpace) {
                    // The widthMode is either UNSPECIFIED or AT_MOST, and
                    // this child is only laid out using excess space. Measure
                    // using WRAP_CONTENT so that we can find out the view's
                    // optimal width. We'll restore the original width of 0
                    // after measurement.
                    lp.width = LayoutParams.WRAP_CONTENT;
                }

                // Determine how big this child would like to be. If this or
                // previous children have given a weight, then we allow it to
                // use all available space (and we will shrink things later
                // if needed).
                final int usedWidth = totalWeight == 0 ? mTotalLength : 0;
                measureChildBeforeLayout(child, i, widthMeasureSpec, usedWidth,
                        heightMeasureSpec, 0);

                final int childWidth = child.getMeasuredWidth();
                if (useExcessSpace) {
                    // Restore the original width and record how much space
                    // we've allocated to excess-only children so that we can
                    // match the behavior of EXACTLY measurement.
                    lp.width = 0;
                    usedExcessSpace += childWidth;
                }

                if (isExactly) {
                    mTotalLength += childWidth + lp.leftMargin + lp.rightMargin
                            + getNextLocationOffset(child);
                } else {
                    final int totalLength = mTotalLength;
                    mTotalLength = Math.max(totalLength, totalLength + childWidth + lp.leftMargin
                            + lp.rightMargin + getNextLocationOffset(child));
                }

                if (useLargestChild) {
                    largestChildWidth = Math.max(childWidth, largestChildWidth);
                }
            }

            boolean matchHeightLocally = false;
            if (heightMode != MeasureSpec.EXACTLY && lp.height == LayoutParams.MATCH_PARENT) {
                // The height of the linear layout will scale, and at least one
                // child said it wanted to match our height. Set a flag indicating that
                // we need to remeasure at least that view when we know our height.
                matchHeight = true;
                matchHeightLocally = true;
            }

            final int margin = lp.topMargin + lp.bottomMargin;
            final int childHeight = child.getMeasuredHeight() + margin;
            childState = combineMeasuredStates(childState, child.getMeasuredState());

            if (baselineAligned) {
                final int childBaseline = child.getBaseline();
                if (childBaseline != -1) {
                    // Translates the child's vertical gravity into an index
                    // in the range 0..VERTICAL_GRAVITY_COUNT
                    final int gravity = (lp.gravity < 0 ? mGravity : lp.gravity)
                            & Gravity.VERTICAL_GRAVITY_MASK;
                    final int index = ((gravity >> Gravity.AXIS_Y_SHIFT)
                            & ~Gravity.AXIS_SPECIFIED) >> 1;

                    maxAscent[index] = Math.max(maxAscent[index], childBaseline);
                    maxDescent[index] = Math.max(maxDescent[index], childHeight - childBaseline);
                }
            }

            maxHeight = Math.max(maxHeight, childHeight);

            allFillParent = allFillParent && lp.height == LayoutParams.MATCH_PARENT;
            if (lp.weight > 0) {
                /*
                 * Heights of weighted Views are bogus if we end up
                 * remeasuring, so keep them separate.
                 */
                weightedMaxHeight = Math.max(weightedMaxHeight,
                        matchHeightLocally ? margin : childHeight);
            } else {
                alternativeMaxHeight = Math.max(alternativeMaxHeight,
                        matchHeightLocally ? margin : childHeight);
            }

            i += getChildrenSkipCount(child, i);
        }

        if (nonSkippedChildCount > 0 && hasDividerBeforeChildAt(count)) {
            mTotalLength += mDividerWidth;
        }

        // Check mMaxAscent[INDEX_TOP] first because it maps to Gravity.TOP,
        // the most common case
        if (maxAscent[INDEX_TOP] != -1 ||
                maxAscent[INDEX_CENTER_VERTICAL] != -1 ||
                maxAscent[INDEX_BOTTOM] != -1 ||
                maxAscent[INDEX_FILL] != -1) {
            final int ascent = Math.max(maxAscent[INDEX_FILL],
                    Math.max(maxAscent[INDEX_CENTER_VERTICAL],
                    Math.max(maxAscent[INDEX_TOP], maxAscent[INDEX_BOTTOM])));
            final int descent = Math.max(maxDescent[INDEX_FILL],
                    Math.max(maxDescent[INDEX_CENTER_VERTICAL],
                    Math.max(maxDescent[INDEX_TOP], maxDescent[INDEX_BOTTOM])));
            maxHeight = Math.max(maxHeight, ascent + descent);
        }

        if (useLargestChild &&
                (widthMode == MeasureSpec.AT_MOST || widthMode == MeasureSpec.UNSPECIFIED)) {
            mTotalLength = 0;

            for (int i = 0; i < count; ++i) {
                final View child = getVirtualChildAt(i);
                if (child == null) {
                    mTotalLength += measureNullChild(i);
                    continue;
                }

                if (child.getVisibility() == GONE) {
                    i += getChildrenSkipCount(child, i);
                    continue;
                }

                final LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)
                        child.getLayoutParams();
                if (isExactly) {
                    mTotalLength += largestChildWidth + lp.leftMargin + lp.rightMargin +
                            getNextLocationOffset(child);
                } else {
                    final int totalLength = mTotalLength;
                    mTotalLength = Math.max(totalLength, totalLength + largestChildWidth +
                            lp.leftMargin + lp.rightMargin + getNextLocationOffset(child));
                }
            }
        }

        // Add in our padding
        mTotalLength += mPaddingLeft + mPaddingRight;

        int widthSize = mTotalLength;

        // Check against our minimum width
        widthSize = Math.max(widthSize, getSuggestedMinimumWidth());

        // Reconcile our calculated size with the widthMeasureSpec
        int widthSizeAndState = resolveSizeAndState(widthSize, widthMeasureSpec, 0);
        widthSize = widthSizeAndState & MEASURED_SIZE_MASK;

        // Either expand children with weight to take up available space or
        // shrink them if they extend beyond our current bounds. If we skipped
        // measurement on any children, we need to measure them now.
        int remainingExcess = widthSize - mTotalLength
                + (mAllowInconsistentMeasurement ? 0 : usedExcessSpace);
        if (skippedMeasure
                || ((sRemeasureWeightedChildren || remainingExcess != 0) && totalWeight > 0.0f)) {
            float remainingWeightSum = mWeightSum > 0.0f ? mWeightSum : totalWeight;

            maxAscent[0] = maxAscent[1] = maxAscent[2] = maxAscent[3] = -1;
            maxDescent[0] = maxDescent[1] = maxDescent[2] = maxDescent[3] = -1;
            maxHeight = -1;

            mTotalLength = 0;

            for (int i = 0; i < count; ++i) {
                final View child = getVirtualChildAt(i);
                if (child == null || child.getVisibility() == View.GONE) {
                    continue;
                }

                final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                final float childWeight = lp.weight;
                if (childWeight > 0) {
                    final int share = (int) (childWeight * remainingExcess / remainingWeightSum);
                    remainingExcess -= share;
                    remainingWeightSum -= childWeight;

                    final int childWidth;
                    if (mUseLargestChild && widthMode != MeasureSpec.EXACTLY) {
                        childWidth = largestChildWidth;
                    } else if (lp.width == 0 && (!mAllowInconsistentMeasurement
                            || widthMode == MeasureSpec.EXACTLY)) {
                        // This child needs to be laid out from scratch using
                        // only its share of excess space.
                        childWidth = share;
                    } else {
                        // This child had some intrinsic width to which we
                        // need to add its share of excess space.
                        childWidth = child.getMeasuredWidth() + share;
                    }

                    final int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(
                            Math.max(0, childWidth), MeasureSpec.EXACTLY);
                    final int childHeightMeasureSpec = getChildMeasureSpec(heightMeasureSpec,
                            mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin,
                            lp.height);
                    child.measure(childWidthMeasureSpec, childHeightMeasureSpec);

                    // Child may now not fit in horizontal dimension.
                    childState = combineMeasuredStates(childState,
                            child.getMeasuredState() & MEASURED_STATE_MASK);
                }

                if (isExactly) {
                    mTotalLength += child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin +
                            getNextLocationOffset(child);
                } else {
                    final int totalLength = mTotalLength;
                    mTotalLength = Math.max(totalLength, totalLength + child.getMeasuredWidth() +
                            lp.leftMargin + lp.rightMargin + getNextLocationOffset(child));
                }

                boolean matchHeightLocally = heightMode != MeasureSpec.EXACTLY &&
                        lp.height == LayoutParams.MATCH_PARENT;

                final int margin = lp.topMargin + lp .bottomMargin;
                int childHeight = child.getMeasuredHeight() + margin;
                maxHeight = Math.max(maxHeight, childHeight);
                alternativeMaxHeight = Math.max(alternativeMaxHeight,
                        matchHeightLocally ? margin : childHeight);

                allFillParent = allFillParent && lp.height == LayoutParams.MATCH_PARENT;

                if (baselineAligned) {
                    final int childBaseline = child.getBaseline();
                    if (childBaseline != -1) {
                        // Translates the child's vertical gravity into an index in the range 0..2
                        final int gravity = (lp.gravity < 0 ? mGravity : lp.gravity)
                                & Gravity.VERTICAL_GRAVITY_MASK;
                        final int index = ((gravity >> Gravity.AXIS_Y_SHIFT)
                                & ~Gravity.AXIS_SPECIFIED) >> 1;

                        maxAscent[index] = Math.max(maxAscent[index], childBaseline);
                        maxDescent[index] = Math.max(maxDescent[index],
                                childHeight - childBaseline);
                    }
                }
            }

            // Add in our padding
            mTotalLength += mPaddingLeft + mPaddingRight;
            // TODO: Should we update widthSize with the new total length?

            // Check mMaxAscent[INDEX_TOP] first because it maps to Gravity.TOP,
            // the most common case
            if (maxAscent[INDEX_TOP] != -1 ||
                    maxAscent[INDEX_CENTER_VERTICAL] != -1 ||
                    maxAscent[INDEX_BOTTOM] != -1 ||
                    maxAscent[INDEX_FILL] != -1) {
                final int ascent = Math.max(maxAscent[INDEX_FILL],
                        Math.max(maxAscent[INDEX_CENTER_VERTICAL],
                        Math.max(maxAscent[INDEX_TOP], maxAscent[INDEX_BOTTOM])));
                final int descent = Math.max(maxDescent[INDEX_FILL],
                        Math.max(maxDescent[INDEX_CENTER_VERTICAL],
                        Math.max(maxDescent[INDEX_TOP], maxDescent[INDEX_BOTTOM])));
                maxHeight = Math.max(maxHeight, ascent + descent);
            }
        } else {
            alternativeMaxHeight = Math.max(alternativeMaxHeight, weightedMaxHeight);

            // We have no limit, so make all weighted views as wide as the largest child.
            // Children will have already been measured once.
            if (useLargestChild && widthMode != MeasureSpec.EXACTLY) {
                for (int i = 0; i < count; i++) {
                    final View child = getVirtualChildAt(i);
                    if (child == null || child.getVisibility() == View.GONE) {
                        continue;
                    }

                    final LinearLayout.LayoutParams lp =
                            (LinearLayout.LayoutParams) child.getLayoutParams();

                    float childExtra = lp.weight;
                    if (childExtra > 0) {
                        child.measure(
                                MeasureSpec.makeMeasureSpec(largestChildWidth, MeasureSpec.EXACTLY),
                                MeasureSpec.makeMeasureSpec(child.getMeasuredHeight(),
                                        MeasureSpec.EXACTLY));
                    }
                }
            }
        }

        if (!allFillParent && heightMode != MeasureSpec.EXACTLY) {
            maxHeight = alternativeMaxHeight;
        }

        maxHeight += mPaddingTop + mPaddingBottom;

        // Check against our minimum height
        maxHeight = Math.max(maxHeight, getSuggestedMinimumHeight());

        setMeasuredDimension(widthSizeAndState | (childState&MEASURED_STATE_MASK),
                resolveSizeAndState(maxHeight, heightMeasureSpec,
                        (childState<<MEASURED_HEIGHT_STATE_SHIFT)));

        if (matchHeight) {
            forceUniformHeight(count, widthMeasureSpec);
        }
    }

    private void forceUniformHeight(int count, int widthMeasureSpec) {
        // Pretend that the linear layout has an exact size. This is the measured height of
        // ourselves. The measured height should be the max height of the children, changed
        // to accommodate the heightMeasureSpec from the parent
        int uniformMeasureSpec = MeasureSpec.makeMeasureSpec(getMeasuredHeight(),
                MeasureSpec.EXACTLY);
        for (int i = 0; i < count; ++i) {
           final View child = getVirtualChildAt(i);
           if (child != null && child.getVisibility() != GONE) {
               LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) child.getLayoutParams();

               if (lp.height == LayoutParams.MATCH_PARENT) {
                   // Temporarily force children to reuse their old measured width
                   // FIXME: this may not be right for something like wrapping text?
                   int oldWidth = lp.width;
                   lp.width = child.getMeasuredWidth();

                   // Remeasure with new dimensions
                   measureChildWithMargins(child, widthMeasureSpec, 0, uniformMeasureSpec, 0);
                   lp.width = oldWidth;
               }
           }
        }
    }

    
Returns the number of children to skip after measuring/laying out
the specified child.
Params:
child – the child after which we want to skip children
index – the index of the child after which we want to skip children
Returns:
the number of children to skip, 0 by default/**
     * <p>Returns the number of children to skip after measuring/laying out
     * the specified child.</p>
     *
     * @param child the child after which we want to skip children
     * @param index the index of the child after which we want to skip children
     * @return the number of children to skip, 0 by default
     */
    int getChildrenSkipCount(View child, int index) {
        return 0;
    }

    
Returns the size (width or height) that should be occupied by a null
child.
Params:
childIndex – the index of the null child
Returns:
the width or height of the child depending on the orientation/**
     * <p>Returns the size (width or height) that should be occupied by a null
     * child.</p>
     *
     * @param childIndex the index of the null child
     * @return the width or height of the child depending on the orientation
     */
    int measureNullChild(int childIndex) {
        return 0;
    }

    
Measure the child according to the parent's measure specs. This method should be overridden by subclasses to force the sizing of children. This method is called by measureVertical(int, int) and measureHorizontal(int, int).
Params:
child – the child to measure
childIndex – the index of the child in this view
widthMeasureSpec – horizontal space requirements as imposed by the parent
totalWidth – extra space that has been used up by the parent horizontally
heightMeasureSpec – vertical space requirements as imposed by the parent
totalHeight – extra space that has been used up by the parent vertically/**
     * <p>Measure the child according to the parent's measure specs. This
     * method should be overridden by subclasses to force the sizing of
     * children. This method is called by {@link #measureVertical(int, int)} and
     * {@link #measureHorizontal(int, int)}.</p>
     *
     * @param child the child to measure
     * @param childIndex the index of the child in this view
     * @param widthMeasureSpec horizontal space requirements as imposed by the parent
     * @param totalWidth extra space that has been used up by the parent horizontally
     * @param heightMeasureSpec vertical space requirements as imposed by the parent
     * @param totalHeight extra space that has been used up by the parent vertically
     */
    void measureChildBeforeLayout(View child, int childIndex,
            int widthMeasureSpec, int totalWidth, int heightMeasureSpec,
            int totalHeight) {
        measureChildWithMargins(child, widthMeasureSpec, totalWidth,
                heightMeasureSpec, totalHeight);
    }

    
Return the location offset of the specified child. This can be used
by subclasses to change the location of a given widget.
Params:
child – the child for which to obtain the location offset
Returns:
the location offset in pixels/**
     * <p>Return the location offset of the specified child. This can be used
     * by subclasses to change the location of a given widget.</p>
     *
     * @param child the child for which to obtain the location offset
     * @return the location offset in pixels
     */
    int getLocationOffset(View child) {
        return 0;
    }

    
Return the size offset of the next sibling of the specified child.
This can be used by subclasses to change the location of the widget
following child.
Params:
child – the child whose next sibling will be moved
Returns:
the location offset of the next child in pixels/**
     * <p>Return the size offset of the next sibling of the specified child.
     * This can be used by subclasses to change the location of the widget
     * following <code>child</code>.</p>
     *
     * @param child the child whose next sibling will be moved
     * @return the location offset of the next child in pixels
     */
    int getNextLocationOffset(View child) {
        return 0;
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        if (mOrientation == VERTICAL) {
            layoutVertical(l, t, r, b);
        } else {
            layoutHorizontal(l, t, r, b);
        }
    }

    
Position the children during a layout pass if the orientation of this LinearLayout is set to VERTICAL. 
Params:
left – 
top – 
right – 
bottom – 
See Also:
getOrientation()
setOrientation(int)
onLayout(boolean, int, int, int, int)/**
     * Position the children during a layout pass if the orientation of this
     * LinearLayout is set to {@link #VERTICAL}.
     *
     * @see #getOrientation()
     * @see #setOrientation(int)
     * @see #onLayout(boolean, int, int, int, int)
     * @param left
     * @param top
     * @param right
     * @param bottom
     */
    void layoutVertical(int left, int top, int right, int bottom) {
        final int paddingLeft = mPaddingLeft;

        int childTop;
        int childLeft;

        // Where right end of child should go
        final int width = right - left;
        int childRight = width - mPaddingRight;

        // Space available for child
        int childSpace = width - paddingLeft - mPaddingRight;

        final int count = getVirtualChildCount();

        final int majorGravity = mGravity & Gravity.VERTICAL_GRAVITY_MASK;
        final int minorGravity = mGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK;

        switch (majorGravity) {
           case Gravity.BOTTOM:
               // mTotalLength contains the padding already
               childTop = mPaddingTop + bottom - top - mTotalLength;
               break;

               // mTotalLength contains the padding already
           case Gravity.CENTER_VERTICAL:
               childTop = mPaddingTop + (bottom - top - mTotalLength) / 2;
               break;

           case Gravity.TOP:
           default:
               childTop = mPaddingTop;
               break;
        }

        for (int i = 0; i < count; i++) {
            final View child = getVirtualChildAt(i);
            if (child == null) {
                childTop += measureNullChild(i);
            } else if (child.getVisibility() != GONE) {
                final int childWidth = child.getMeasuredWidth();
                final int childHeight = child.getMeasuredHeight();

                final LinearLayout.LayoutParams lp =
                        (LinearLayout.LayoutParams) child.getLayoutParams();

                int gravity = lp.gravity;
                if (gravity < 0) {
                    gravity = minorGravity;
                }
                final int layoutDirection = getLayoutDirection();
                final int absoluteGravity = Gravity.getAbsoluteGravity(gravity, layoutDirection);
                switch (absoluteGravity & Gravity.HORIZONTAL_GRAVITY_MASK) {
                    case Gravity.CENTER_HORIZONTAL:
                        childLeft = paddingLeft + ((childSpace - childWidth) / 2)
                                + lp.leftMargin - lp.rightMargin;
                        break;

                    case Gravity.RIGHT:
                        childLeft = childRight - childWidth - lp.rightMargin;
                        break;

                    case Gravity.LEFT:
                    default:
                        childLeft = paddingLeft + lp.leftMargin;
                        break;
                }

                if (hasDividerBeforeChildAt(i)) {
                    childTop += mDividerHeight;
                }

                childTop += lp.topMargin;
                setChildFrame(child, childLeft, childTop + getLocationOffset(child),
                        childWidth, childHeight);
                childTop += childHeight + lp.bottomMargin + getNextLocationOffset(child);

                i += getChildrenSkipCount(child, i);
            }
        }
    }

    @Override
    public void onRtlPropertiesChanged(@ResolvedLayoutDir int layoutDirection) {
        super.onRtlPropertiesChanged(layoutDirection);
        if (layoutDirection != mLayoutDirection) {
            mLayoutDirection = layoutDirection;
            if (mOrientation == HORIZONTAL) {
                requestLayout();
            }
        }
    }

    
Position the children during a layout pass if the orientation of this LinearLayout is set to HORIZONTAL. 
Params:
left – 
top – 
right – 
bottom – 
See Also:
getOrientation()
setOrientation(int)
onLayout(boolean, int, int, int, int)/**
     * Position the children during a layout pass if the orientation of this
     * LinearLayout is set to {@link #HORIZONTAL}.
     *
     * @see #getOrientation()
     * @see #setOrientation(int)
     * @see #onLayout(boolean, int, int, int, int)
     * @param left
     * @param top
     * @param right
     * @param bottom
     */
    void layoutHorizontal(int left, int top, int right, int bottom) {
        final boolean isLayoutRtl = isLayoutRtl();
        final int paddingTop = mPaddingTop;

        int childTop;
        int childLeft;

        // Where bottom of child should go
        final int height = bottom - top;
        int childBottom = height - mPaddingBottom;

        // Space available for child
        int childSpace = height - paddingTop - mPaddingBottom;

        final int count = getVirtualChildCount();

        final int majorGravity = mGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK;
        final int minorGravity = mGravity & Gravity.VERTICAL_GRAVITY_MASK;

        final boolean baselineAligned = mBaselineAligned;

        final int[] maxAscent = mMaxAscent;
        final int[] maxDescent = mMaxDescent;

        final int layoutDirection = getLayoutDirection();
        switch (Gravity.getAbsoluteGravity(majorGravity, layoutDirection)) {
            case Gravity.RIGHT:
                // mTotalLength contains the padding already
                childLeft = mPaddingLeft + right - left - mTotalLength;
                break;

            case Gravity.CENTER_HORIZONTAL:
                // mTotalLength contains the padding already
                childLeft = mPaddingLeft + (right - left - mTotalLength) / 2;
                break;

            case Gravity.LEFT:
            default:
                childLeft = mPaddingLeft;
                break;
        }

        int start = 0;
        int dir = 1;
        //In case of RTL, start drawing from the last child.
        if (isLayoutRtl) {
            start = count - 1;
            dir = -1;
        }

        for (int i = 0; i < count; i++) {
            final int childIndex = start + dir * i;
            final View child = getVirtualChildAt(childIndex);
            if (child == null) {
                childLeft += measureNullChild(childIndex);
            } else if (child.getVisibility() != GONE) {
                final int childWidth = child.getMeasuredWidth();
                final int childHeight = child.getMeasuredHeight();
                int childBaseline = -1;

                final LinearLayout.LayoutParams lp =
                        (LinearLayout.LayoutParams) child.getLayoutParams();

                if (baselineAligned && lp.height != LayoutParams.MATCH_PARENT) {
                    childBaseline = child.getBaseline();
                }

                int gravity = lp.gravity;
                if (gravity < 0) {
                    gravity = minorGravity;
                }

                switch (gravity & Gravity.VERTICAL_GRAVITY_MASK) {
                    case Gravity.TOP:
                        childTop = paddingTop + lp.topMargin;
                        if (childBaseline != -1) {
                            childTop += maxAscent[INDEX_TOP] - childBaseline;
                        }
                        break;

                    case Gravity.CENTER_VERTICAL:
                        // Removed support for baseline alignment when layout_gravity or
                        // gravity == center_vertical. See bug #1038483.
                        // Keep the code around if we need to re-enable this feature
                        // if (childBaseline != -1) {
                        //     // Align baselines vertically only if the child is smaller than us
                        //     if (childSpace - childHeight > 0) {
                        //         childTop = paddingTop + (childSpace / 2) - childBaseline;
                        //     } else {
                        //         childTop = paddingTop + (childSpace - childHeight) / 2;
                        //     }
                        // } else {
                        childTop = paddingTop + ((childSpace - childHeight) / 2)
                                + lp.topMargin - lp.bottomMargin;
                        break;

                    case Gravity.BOTTOM:
                        childTop = childBottom - childHeight - lp.bottomMargin;
                        if (childBaseline != -1) {
                            int descent = child.getMeasuredHeight() - childBaseline;
                            childTop -= (maxDescent[INDEX_BOTTOM] - descent);
                        }
                        break;
                    default:
                        childTop = paddingTop;
                        break;
                }

                if (hasDividerBeforeChildAt(childIndex)) {
                    childLeft += mDividerWidth;
                }

                childLeft += lp.leftMargin;
                setChildFrame(child, childLeft + getLocationOffset(child), childTop,
                        childWidth, childHeight);
                childLeft += childWidth + lp.rightMargin +
                        getNextLocationOffset(child);

                i += getChildrenSkipCount(child, childIndex);
            }
        }
    }

    private void setChildFrame(View child, int left, int top, int width, int height) {
        child.layout(left, top, left + width, top + height);
    }

    
Should the layout be a column or a row.
Params:
orientation – Pass HORIZONTAL or VERTICAL. Default value is HORIZONTAL.
@attr
ref android.R.styleable#LinearLayout_orientation/**
     * Should the layout be a column or a row.
     * @param orientation Pass {@link #HORIZONTAL} or {@link #VERTICAL}. Default
     * value is {@link #HORIZONTAL}.
     *
     * @attr ref android.R.styleable#LinearLayout_orientation
     */
    public void setOrientation(@OrientationMode int orientation) {
        if (mOrientation != orientation) {
            mOrientation = orientation;
            requestLayout();
        }
    }

    
Returns the current orientation.
Returns:
either HORIZONTAL or VERTICAL/**
     * Returns the current orientation.
     *
     * @return either {@link #HORIZONTAL} or {@link #VERTICAL}
     */
    @OrientationMode
    public int getOrientation() {
        return mOrientation;
    }

    
Describes how the child views are positioned. Defaults to GRAVITY_TOP. If
this layout has a VERTICAL orientation, this controls where all the child
views are placed if there is extra vertical space. If this layout has a
HORIZONTAL orientation, this controls the alignment of the children.
Params:
gravity – See Gravity
@attr
ref android.R.styleable#LinearLayout_gravity/**
     * Describes how the child views are positioned. Defaults to GRAVITY_TOP. If
     * this layout has a VERTICAL orientation, this controls where all the child
     * views are placed if there is extra vertical space. If this layout has a
     * HORIZONTAL orientation, this controls the alignment of the children.
     *
     * @param gravity See {@link android.view.Gravity}
     *
     * @attr ref android.R.styleable#LinearLayout_gravity
     */
    @android.view.RemotableViewMethod
    public void setGravity(int gravity) {
        if (mGravity != gravity) {
            if ((gravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK) == 0) {
                gravity |= Gravity.START;
            }

            if ((gravity & Gravity.VERTICAL_GRAVITY_MASK) == 0) {
                gravity |= Gravity.TOP;
            }

            mGravity = gravity;
            requestLayout();
        }
    }

    
Returns the current gravity. See Gravity 
See Also:
setGravity
Returns:
the current gravity./**
     * Returns the current gravity. See {@link android.view.Gravity}
     *
     * @return the current gravity.
     * @see #setGravity
     */
    public int getGravity() {
        return mGravity;
    }

    @android.view.RemotableViewMethod
    public void setHorizontalGravity(int horizontalGravity) {
        final int gravity = horizontalGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK;
        if ((mGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK) != gravity) {
            mGravity = (mGravity & ~Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK) | gravity;
            requestLayout();
        }
    }

    @android.view.RemotableViewMethod
    public void setVerticalGravity(int verticalGravity) {
        final int gravity = verticalGravity & Gravity.VERTICAL_GRAVITY_MASK;
        if ((mGravity & Gravity.VERTICAL_GRAVITY_MASK) != gravity) {
            mGravity = (mGravity & ~Gravity.VERTICAL_GRAVITY_MASK) | gravity;
            requestLayout();
        }
    }

    @Override
    public LayoutParams generateLayoutParams(AttributeSet attrs) {
        return new LinearLayout.LayoutParams(getContext(), attrs);
    }

    
Returns a set of layout parameters with a width of LayoutParams.MATCH_PARENT and a height of LayoutParams.WRAP_CONTENT when the layout's orientation is VERTICAL. When the orientation is HORIZONTAL, the width is set to LayoutParams.WRAP_CONTENT and the height to LayoutParams.WRAP_CONTENT. /**
     * Returns a set of layout parameters with a width of
     * {@link android.view.ViewGroup.LayoutParams#MATCH_PARENT}
     * and a height of {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT}
     * when the layout's orientation is {@link #VERTICAL}. When the orientation is
     * {@link #HORIZONTAL}, the width is set to {@link LayoutParams#WRAP_CONTENT}
     * and the height to {@link LayoutParams#WRAP_CONTENT}.
     */
    @Override
    protected LayoutParams generateDefaultLayoutParams() {
        if (mOrientation == HORIZONTAL) {
            return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        } else if (mOrientation == VERTICAL) {
            return new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
        }
        return null;
    }

    @Override
    protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
        if (sPreserveMarginParamsInLayoutParamConversion) {
            if (lp instanceof LayoutParams) {
                return new LayoutParams((LayoutParams) lp);
            } else if (lp instanceof MarginLayoutParams) {
                return new LayoutParams((MarginLayoutParams) lp);
            }
        }
        return new LayoutParams(lp);
    }


    // Override to allow type-checking of LayoutParams.
    @Override
    protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
        return p instanceof LinearLayout.LayoutParams;
    }

    @Override
    public CharSequence getAccessibilityClassName() {
        return LinearLayout.class.getName();
    }

    
@hide
/** @hide */
    @Override
    protected void encodeProperties(@NonNull ViewHierarchyEncoder encoder) {
        super.encodeProperties(encoder);
        encoder.addProperty("layout:baselineAligned", mBaselineAligned);
        encoder.addProperty("layout:baselineAlignedChildIndex", mBaselineAlignedChildIndex);
        encoder.addProperty("measurement:baselineChildTop", mBaselineChildTop);
        encoder.addProperty("measurement:orientation", mOrientation);
        encoder.addProperty("measurement:gravity", mGravity);
        encoder.addProperty("measurement:totalLength", mTotalLength);
        encoder.addProperty("layout:totalLength", mTotalLength);
        encoder.addProperty("layout:useLargestChild", mUseLargestChild);
    }

    
Per-child layout information associated with ViewLinearLayout.
@attr
ref android.R.styleable#LinearLayout_Layout_layout_weight
@attr
ref android.R.styleable#LinearLayout_Layout_layout_gravity/**
     * Per-child layout information associated with ViewLinearLayout.
     *
     * @attr ref android.R.styleable#LinearLayout_Layout_layout_weight
     * @attr ref android.R.styleable#LinearLayout_Layout_layout_gravity
     */
    public static class LayoutParams extends ViewGroup.MarginLayoutParams {
        
Indicates how much of the extra space in the LinearLayout will be
allocated to the view associated with these LayoutParams. Specify
0 if the view should not be stretched. Otherwise the extra pixels
will be pro-rated among all views whose weight is greater than 0.
/**
         * Indicates how much of the extra space in the LinearLayout will be
         * allocated to the view associated with these LayoutParams. Specify
         * 0 if the view should not be stretched. Otherwise the extra pixels
         * will be pro-rated among all views whose weight is greater than 0.
         */
        @ViewDebug.ExportedProperty(category = "layout")
        public float weight;

        
Gravity for the view associated with these LayoutParams.
See Also:
Gravity/**
         * Gravity for the view associated with these LayoutParams.
         *
         * @see android.view.Gravity
         */
        @ViewDebug.ExportedProperty(category = "layout", mapping = {
            @ViewDebug.IntToString(from =  -1,                       to = "NONE"),
            @ViewDebug.IntToString(from = Gravity.NO_GRAVITY,        to = "NONE"),
            @ViewDebug.IntToString(from = Gravity.TOP,               to = "TOP"),
            @ViewDebug.IntToString(from = Gravity.BOTTOM,            to = "BOTTOM"),
            @ViewDebug.IntToString(from = Gravity.LEFT,              to = "LEFT"),
            @ViewDebug.IntToString(from = Gravity.RIGHT,             to = "RIGHT"),
            @ViewDebug.IntToString(from = Gravity.START,             to = "START"),
            @ViewDebug.IntToString(from = Gravity.END,               to = "END"),
            @ViewDebug.IntToString(from = Gravity.CENTER_VERTICAL,   to = "CENTER_VERTICAL"),
            @ViewDebug.IntToString(from = Gravity.FILL_VERTICAL,     to = "FILL_VERTICAL"),
            @ViewDebug.IntToString(from = Gravity.CENTER_HORIZONTAL, to = "CENTER_HORIZONTAL"),
            @ViewDebug.IntToString(from = Gravity.FILL_HORIZONTAL,   to = "FILL_HORIZONTAL"),
            @ViewDebug.IntToString(from = Gravity.CENTER,            to = "CENTER"),
            @ViewDebug.IntToString(from = Gravity.FILL,              to = "FILL")
        })
        public int gravity = -1;

        
{@inheritDoc}
/**
         * {@inheritDoc}
         */
        public LayoutParams(Context c, AttributeSet attrs) {
            super(c, attrs);
            TypedArray a =
                    c.obtainStyledAttributes(attrs, com.android.internal.R.styleable.LinearLayout_Layout);

            weight = a.getFloat(com.android.internal.R.styleable.LinearLayout_Layout_layout_weight, 0);
            gravity = a.getInt(com.android.internal.R.styleable.LinearLayout_Layout_layout_gravity, -1);

            a.recycle();
        }

        
{@inheritDoc}
/**
         * {@inheritDoc}
         */
        public LayoutParams(int width, int height) {
            super(width, height);
            weight = 0;
        }

        
Creates a new set of layout parameters with the specified width, height
and weight.
Params:
width – the width, either LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT or a fixed size in pixels
height – the height, either LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT or a fixed size in pixels
weight – the weight/**
         * Creates a new set of layout parameters with the specified width, height
         * and weight.
         *
         * @param width the width, either {@link #MATCH_PARENT},
         *        {@link #WRAP_CONTENT} or a fixed size in pixels
         * @param height the height, either {@link #MATCH_PARENT},
         *        {@link #WRAP_CONTENT} or a fixed size in pixels
         * @param weight the weight
         */
        public LayoutParams(int width, int height, float weight) {
            super(width, height);
            this.weight = weight;
        }

        
{@inheritDoc}
/**
         * {@inheritDoc}
         */
        public LayoutParams(ViewGroup.LayoutParams p) {
            super(p);
        }

        
{@inheritDoc}
/**
         * {@inheritDoc}
         */
        public LayoutParams(ViewGroup.MarginLayoutParams source) {
            super(source);
        }

        
Copy constructor. Clones the width, height, margin values, weight,
and gravity of the source.
Params:
source – The layout params to copy from./**
         * Copy constructor. Clones the width, height, margin values, weight,
         * and gravity of the source.
         *
         * @param source The layout params to copy from.
         */
        public LayoutParams(LayoutParams source) {
            super(source);

            this.weight = source.weight;
            this.gravity = source.gravity;
        }

        @Override
        public String debug(String output) {
            return output + "LinearLayout.LayoutParams={width=" + sizeToString(width) +
                    ", height=" + sizeToString(height) + " weight=" + weight +  "}";
        }

        
@hide
/** @hide */
        @Override
        protected void encodeProperties(@NonNull ViewHierarchyEncoder encoder) {
            super.encodeProperties(encoder);

            encoder.addProperty("layout:weight", weight);
            encoder.addProperty("layout:gravity", gravity);
        }
    }
}