core/java/com/android/internal/widget/ActionBarContainer.java

/*
 * 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 com.android.internal.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.ActionMode;
import android.view.MotionEvent;
import android.view.View;
import android.widget.FrameLayout;

/**
 * This class acts as a container for the action bar view and action mode context views.
 * It applies special styles as needed to help handle animated transitions between them.
 * @hide
 */
public class ActionBarContainer extends FrameLayout {
    private boolean mIsTransitioning;
    private View mTabContainer;

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

    public ActionBarContainer(Context context, AttributeSet attrs) {
        super(context, attrs);

        TypedArray a = context.obtainStyledAttributes(attrs,
                com.android.internal.R.styleable.ActionBar);
        setBackgroundDrawable(a.getDrawable(com.android.internal.R.styleable.ActionBar_background));
        a.recycle();
    }

    /**
     * Set the action bar into a "transitioning" state. While transitioning
     * the bar will block focus and touch from all of its descendants. This
     * prevents the user from interacting with the bar while it is animating
     * in or out.
     *
     * @param isTransitioning true if the bar is currently transitioning, false otherwise.
     */
    public void setTransitioning(boolean isTransitioning) {
        mIsTransitioning = isTransitioning;
        setDescendantFocusability(isTransitioning ? FOCUS_BLOCK_DESCENDANTS
                : FOCUS_AFTER_DESCENDANTS);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        return mIsTransitioning || super.onInterceptTouchEvent(ev);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        super.onTouchEvent(ev);

        // An action bar always eats touch events.
        return true;
    }

    public void setTabContainer(View tabView) {
        if (mTabContainer != null) {
            removeView(mTabContainer);
        }
        mTabContainer = tabView;
        addView(tabView);
    }

    public View getTabContainer() {
        return mTabContainer;
    }

    @Override
    public ActionMode startActionModeForChild(View child, ActionMode.Callback callback) {
        // No starting an action mode for an action bar child! (Where would it go?)
        return null;
    }

    @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (mTabContainer != null && mTabContainer.getVisibility() != GONE) {
            final int mode = MeasureSpec.getMode(heightMeasureSpec);
            if (mode == MeasureSpec.AT_MOST) {
                final int measuredHeight = getMeasuredHeight();
                final int maxHeight = MeasureSpec.getSize(heightMeasureSpec);
                setMeasuredDimension(getMeasuredWidth(),
                        Math.min(measuredHeight + mTabContainer.getMeasuredHeight(), maxHeight));
            }
        }
    }

    @Override
    public void onLayout(boolean changed, int l, int t, int r, int b) {
        super.onLayout(changed, l, t, r, b);
        if (mTabContainer != null && mTabContainer.getVisibility() != GONE) {
            final int containerHeight = getMeasuredHeight();
            mTabContainer.layout(l, containerHeight - mTabContainer.getMeasuredHeight(),
                    r, containerHeight);
        }
    }
}