/*
 * 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.view;

import android.annotation.StyleRes;
import android.content.Context;
import android.content.ContextWrapper;
import android.content.res.AssetManager;
import android.content.res.Configuration;
import android.content.res.Resources;

A context wrapper that allows you to modify or replace the theme of the
wrapped context.
/**
 * A context wrapper that allows you to modify or replace the theme of the
 * wrapped context.
 */
public class ContextThemeWrapper extends ContextWrapper {
    private int mThemeResource;
    private Resources.Theme mTheme;
    private LayoutInflater mInflater;
    private Configuration mOverrideConfiguration;
    private Resources mResources;

    
Creates a new context wrapper with no theme and no base context.

Note: A base context must be attached using attachBaseContext(Context) before calling any other method on the newly constructed context wrapper. /**
     * Creates a new context wrapper with no theme and no base context.
     * <p class="note">
     * <strong>Note:</strong> A base context <strong>must</strong> be attached
     * using {@link #attachBaseContext(Context)} before calling any other
     * method on the newly constructed context wrapper.
     */
    public ContextThemeWrapper() {
        super(null);
    }

    
Creates a new context wrapper with the specified theme.

The specified theme will be applied on top of the base context's theme.
Any attributes not explicitly defined in the theme identified by
themeResId will retain their original values.
Params:
base – the base context
themeResId – the resource ID of the theme to be applied on top of
                  the base context's theme/**
     * Creates a new context wrapper with the specified theme.
     * <p>
     * The specified theme will be applied on top of the base context's theme.
     * Any attributes not explicitly defined in the theme identified by
     * <var>themeResId</var> will retain their original values.
     *
     * @param base the base context
     * @param themeResId the resource ID of the theme to be applied on top of
     *                   the base context's theme
     */
    public ContextThemeWrapper(Context base, @StyleRes int themeResId) {
        super(base);
        mThemeResource = themeResId;
    }

    
Creates a new context wrapper with the specified theme.
 Unlike ContextThemeWrapper(Context, int), the theme passed to this constructor will completely replace the base context's theme. 
Params:
base – the base context
theme – the theme against which resources should be inflated/**
     * Creates a new context wrapper with the specified theme.
     * <p>
     * Unlike {@link #ContextThemeWrapper(Context, int)}, the theme passed to
     * this constructor will completely replace the base context's theme.
     *
     * @param base the base context
     * @param theme the theme against which resources should be inflated
     */
    public ContextThemeWrapper(Context base, Resources.Theme theme) {
        super(base);
        mTheme = theme;
    }

    @Override
    protected void attachBaseContext(Context newBase) {
        super.attachBaseContext(newBase);
    }

    
Call to set an "override configuration" on this context -- this is a configuration that replies one or more values of the standard configuration that is applied to the context. See Context.createConfigurationContext(Configuration) for more information. 
This method can only be called once, and must be called before any calls to getResources() or getAssets() are made. /**
     * Call to set an "override configuration" on this context -- this is
     * a configuration that replies one or more values of the standard
     * configuration that is applied to the context.  See
     * {@link Context#createConfigurationContext(Configuration)} for more
     * information.
     *
     * <p>This method can only be called once, and must be called before any
     * calls to {@link #getResources()} or {@link #getAssets()} are made.
     */
    public void applyOverrideConfiguration(Configuration overrideConfiguration) {
        if (mResources != null) {
            throw new IllegalStateException(
                    "getResources() or getAssets() has already been called");
        }
        if (mOverrideConfiguration != null) {
            throw new IllegalStateException("Override configuration has already been set");
        }
        mOverrideConfiguration = new Configuration(overrideConfiguration);
    }

    
Used by ActivityThread to apply the overridden configuration to onConfigurationChange
callbacks.
@hide
/**
     * Used by ActivityThread to apply the overridden configuration to onConfigurationChange
     * callbacks.
     * @hide
     */
    public Configuration getOverrideConfiguration() {
        return mOverrideConfiguration;
    }

    @Override
    public AssetManager getAssets() {
        // Ensure we're returning assets with the correct configuration.
        return getResourcesInternal().getAssets();
    }

    @Override
    public Resources getResources() {
        return getResourcesInternal();
    }

    private Resources getResourcesInternal() {
        if (mResources == null) {
            if (mOverrideConfiguration == null) {
                mResources = super.getResources();
            } else {
                final Context resContext = createConfigurationContext(mOverrideConfiguration);
                mResources = resContext.getResources();
            }
        }
        return mResources;
    }

    @Override
    public void setTheme(int resid) {
        if (mThemeResource != resid) {
            mThemeResource = resid;
            initializeTheme();
        }
    }

    
@hide
/** @hide */
    @Override
    public int getThemeResId() {
        return mThemeResource;
    }

    @Override
    public Resources.Theme getTheme() {
        if (mTheme != null) {
            return mTheme;
        }

        mThemeResource = Resources.selectDefaultTheme(mThemeResource,
                getApplicationInfo().targetSdkVersion);
        initializeTheme();

        return mTheme;
    }

    @Override
    public Object getSystemService(String name) {
        if (LAYOUT_INFLATER_SERVICE.equals(name)) {
            if (mInflater == null) {
                mInflater = LayoutInflater.from(getBaseContext()).cloneInContext(this);
            }
            return mInflater;
        }
        return getBaseContext().getSystemService(name);
    }

    
Called by setTheme and getTheme to apply a theme resource to the current Theme object. May be overridden to change the default (simple) behavior. This method will not be called in multiple threads simultaneously. 
Params:
theme – the theme being modified
resId – the style resource being applied to theme
first – true if this is the first time a style is being applied to theme/**
     * Called by {@link #setTheme} and {@link #getTheme} to apply a theme
     * resource to the current Theme object. May be overridden to change the
     * default (simple) behavior. This method will not be called in multiple
     * threads simultaneously.
     *
     * @param theme the theme being modified
     * @param resId the style resource being applied to <var>theme</var>
     * @param first {@code true} if this is the first time a style is being
     *              applied to <var>theme</var>
     */
    protected void onApplyThemeResource(Resources.Theme theme, int resId, boolean first) {
        theme.applyStyle(resId, true);
    }

    private void initializeTheme() {
        final boolean first = mTheme == null;
        if (first) {
            mTheme = getResources().newTheme();
            final Resources.Theme theme = getBaseContext().getTheme();
            if (theme != null) {
                mTheme.setTo(theme);
            }
        }
        onApplyThemeResource(mTheme, mThemeResource, first);
    }
}