https://source.android.com/ 
/*
 * Copyright (C) 2010 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.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.res.TypedArray;
import android.os.Message;
import android.util.AttributeSet;
import android.util.Log;
import android.view.RemotableViewMethod;
import android.widget.RemoteViews.RemoteView;


Simple ViewAnimator that will animate between two or more views that have been added to it. Only one child is shown at a time. If requested, can automatically flip between each child at a regular interval. 
@attrref android.R.styleable#AdapterViewFlipper_flipInterval
@attrref android.R.styleable#AdapterViewFlipper_autoStart
/**
 * Simple {@link ViewAnimator} that will animate between two or more views
 * that have been added to it.  Only one child is shown at a time.  If
 * requested, can automatically flip between each child at a regular interval.
 *
 * @attr ref android.R.styleable#AdapterViewFlipper_flipInterval
 * @attr ref android.R.styleable#AdapterViewFlipper_autoStart
 */
@RemoteView
public class AdapterViewFlipper extends AdapterViewAnimator {
    private static final String TAG = "ViewFlipper";
    private static final boolean LOGD = false;

    private static final int DEFAULT_INTERVAL = 10000;

    private int mFlipInterval = DEFAULT_INTERVAL;
    private boolean mAutoStart = false;

    private boolean mRunning = false;
    private boolean mStarted = false;
    private boolean mVisible = false;
    private boolean mUserPresent = true;
    private boolean mAdvancedByHost = false;

    public AdapterViewFlipper(Context context) {
        super(context);
    }

    public AdapterViewFlipper(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public AdapterViewFlipper(Context context, AttributeSet attrs, int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

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

        final TypedArray a = context.obtainStyledAttributes(attrs,
                com.android.internal.R.styleable.AdapterViewFlipper, defStyleAttr, defStyleRes);
        mFlipInterval = a.getInt(
                com.android.internal.R.styleable.AdapterViewFlipper_flipInterval, DEFAULT_INTERVAL);
        mAutoStart = a.getBoolean(
                com.android.internal.R.styleable.AdapterViewFlipper_autoStart, false);

        // A view flipper should cycle through the views
        mLoopViews = true;

        a.recycle();
    }

    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            final String action = intent.getAction();
            if (Intent.ACTION_SCREEN_OFF.equals(action)) {
                mUserPresent = false;
                updateRunning();
            } else if (Intent.ACTION_USER_PRESENT.equals(action)) {
                mUserPresent = true;
                updateRunning(false);
            }
        }
    };

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();

        // Listen for broadcasts related to user-presence
        final IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        filter.addAction(Intent.ACTION_USER_PRESENT);

        // OK, this is gross but needed. This class is supported by the
        // remote views machanism and as a part of that the remote views
        // can be inflated by a context for another user without the app
        // having interact users permission - just for loading resources.
        // For exmaple, when adding widgets from a user profile to the
        // home screen. Therefore, we register the receiver as the current
        // user not the one the context is for.
        getContext().registerReceiverAsUser(mReceiver, android.os.Process.myUserHandle(),
                filter, null, getHandler());


        if (mAutoStart) {
            // Automatically start when requested
            startFlipping();
        }
    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        mVisible = false;

        getContext().unregisterReceiver(mReceiver);
        updateRunning();
    }

    @Override
    protected void onWindowVisibilityChanged(int visibility) {
        super.onWindowVisibilityChanged(visibility);
        mVisible = (visibility == VISIBLE);
        updateRunning(false);
    }

    @Override
    public void setAdapter(Adapter adapter) {
        super.setAdapter(adapter);
        updateRunning();
    }

    
Returns the flip interval, in milliseconds.

See Also:
Returns:the flip interval in milliseconds
@attrref android.R.styleable#AdapterViewFlipper_flipInterval
/**
     * Returns the flip interval, in milliseconds.
     *
     * @return the flip interval in milliseconds
     *
     * @see #setFlipInterval(int)
     *
     * @attr ref android.R.styleable#AdapterViewFlipper_flipInterval
     */
    public int getFlipInterval() {
        return mFlipInterval;
    }

    
How long to wait before flipping to the next view.

Params:
  • flipInterval – flip interval in milliseconds
See Also:
@attrref android.R.styleable#AdapterViewFlipper_flipInterval
/**
     * How long to wait before flipping to the next view.
     *
     * @param flipInterval flip interval in milliseconds
     *
     * @see #getFlipInterval()
     *
     * @attr ref android.R.styleable#AdapterViewFlipper_flipInterval
     */
    public void setFlipInterval(int flipInterval) {
        mFlipInterval = flipInterval;
    }

    
Start a timer to cycle through child views

/**
     * Start a timer to cycle through child views
     */
    public void startFlipping() {
        mStarted = true;
        updateRunning();
    }

    
No more flips

/**
     * No more flips
     */
    public void stopFlipping() {
        mStarted = false;
        updateRunning();
    }

    
{@inheritDoc}

/**
    * {@inheritDoc}
    */
   @Override
   @RemotableViewMethod
   public void showNext() {
       // if the flipper is currently flipping automatically, and showNext() is called
       // we should we should make sure to reset the timer
       if (mRunning) {
           removeCallbacks(mFlipRunnable);
           postDelayed(mFlipRunnable, mFlipInterval);
       }
       super.showNext();
   }

   
{@inheritDoc}

/**
    * {@inheritDoc}
    */
   @Override
   @RemotableViewMethod
   public void showPrevious() {
       // if the flipper is currently flipping automatically, and showPrevious() is called
       // we should we should make sure to reset the timer
       if (mRunning) {
           removeCallbacks(mFlipRunnable);
           postDelayed(mFlipRunnable, mFlipInterval);
       }
       super.showPrevious();
   }

    
Internal method to start or stop dispatching flip Message based on mRunning and mVisible state. 
/**
     * Internal method to start or stop dispatching flip {@link Message} based
     * on {@link #mRunning} and {@link #mVisible} state.
     */
    private void updateRunning() {
        // by default when we update running, we want the
        // current view to animate in
        updateRunning(true);
    }

    
Internal method to start or stop dispatching flip Message based on mRunning and mVisible state. 
Params:
  • flipNow – Determines whether or not to execute the animation now, in
           addition to queuing future flips. If omitted, defaults to
           true.
/**
     * Internal method to start or stop dispatching flip {@link Message} based
     * on {@link #mRunning} and {@link #mVisible} state.
     *
     * @param flipNow Determines whether or not to execute the animation now, in
     *            addition to queuing future flips. If omitted, defaults to
     *            true.
     */
    private void updateRunning(boolean flipNow) {
        boolean running = !mAdvancedByHost && mVisible && mStarted && mUserPresent
                && mAdapter != null;
        if (running != mRunning) {
            if (running) {
                showOnly(mWhichChild, flipNow);
                postDelayed(mFlipRunnable, mFlipInterval);
            } else {
                removeCallbacks(mFlipRunnable);
            }
            mRunning = running;
        }
        if (LOGD) {
            Log.d(TAG, "updateRunning() mVisible=" + mVisible + ", mStarted=" + mStarted
                    + ", mUserPresent=" + mUserPresent + ", mRunning=" + mRunning);
        }
    }

    
Returns true if the child views are flipping.

/**
     * Returns true if the child views are flipping.
     */
    public boolean isFlipping() {
        return mStarted;
    }

    
Set if this view automatically calls startFlipping() when it becomes attached to a window. 
/**
     * Set if this view automatically calls {@link #startFlipping()} when it
     * becomes attached to a window.
     */
    public void setAutoStart(boolean autoStart) {
        mAutoStart = autoStart;
    }

    
Returns true if this view automatically calls startFlipping() when it becomes attached to a window. 
/**
     * Returns true if this view automatically calls {@link #startFlipping()}
     * when it becomes attached to a window.
     */
    public boolean isAutoStart() {
        return mAutoStart;
    }

    private final Runnable mFlipRunnable = new Runnable() {
        @Override
        public void run() {
            if (mRunning) {
                showNext();
            }
        }
    };

    
Called by an AppWidgetHost to indicate that it will be automatically advancing the views of this AdapterViewFlipper by calling AdapterViewAnimator.advance() at some point in the future. This allows AdapterViewFlipper to prepare by no longer Advancing its children. 
/**
     * Called by an {@link android.appwidget.AppWidgetHost} to indicate that it will be
     * automatically advancing the views of this {@link AdapterViewFlipper} by calling
     * {@link AdapterViewFlipper#advance()} at some point in the future. This allows
     * {@link AdapterViewFlipper} to prepare by no longer Advancing its children.
     */
    @Override
    public void fyiWillBeAdvancedByHostKThx() {
        mAdvancedByHost = true;
        updateRunning(false);
    }

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