| /* |
| * Copyright (C) 2014 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.graphics.Canvas; |
| import android.graphics.PixelFormat; |
| import android.graphics.drawable.Drawable; |
| import android.view.View; |
| import android.view.ViewGroup; |
| |
| /** |
| * Helper class for drawing a fallback background in framework decor layouts. |
| * Useful for when an app has not set a window background but we're asked to draw |
| * an uncovered area. |
| */ |
| public class BackgroundFallback { |
| private Drawable mBackgroundFallback; |
| |
| public void setDrawable(Drawable d) { |
| mBackgroundFallback = d; |
| } |
| |
| public boolean hasFallback() { |
| return mBackgroundFallback != null; |
| } |
| |
| /** |
| * Draws the fallback background. |
| * |
| * @param boundsView The view determining with which bounds the background should be drawn. |
| * @param root The view group containing the content. |
| * @param c The canvas to draw the background onto. |
| * @param content The view where the actual app content is contained in. |
| */ |
| public void draw(ViewGroup boundsView, ViewGroup root, Canvas c, View content) { |
| if (!hasFallback()) { |
| return; |
| } |
| |
| // Draw the fallback in the padding. |
| final int width = boundsView.getWidth(); |
| final int height = boundsView.getHeight(); |
| int left = width; |
| int top = height; |
| int right = 0; |
| int bottom = 0; |
| |
| final int childCount = root.getChildCount(); |
| for (int i = 0; i < childCount; i++) { |
| final View child = root.getChildAt(i); |
| final Drawable childBg = child.getBackground(); |
| if (child == content) { |
| // We always count the content view container unless it has no background |
| // and no children. |
| if (childBg == null && child instanceof ViewGroup && |
| ((ViewGroup) child).getChildCount() == 0) { |
| continue; |
| } |
| } else if (child.getVisibility() != View.VISIBLE || childBg == null || |
| childBg.getOpacity() != PixelFormat.OPAQUE) { |
| // Potentially translucent or invisible children don't count, and we assume |
| // the content view will cover the whole area if we're in a background |
| // fallback situation. |
| continue; |
| } |
| left = Math.min(left, child.getLeft()); |
| top = Math.min(top, child.getTop()); |
| right = Math.max(right, child.getRight()); |
| bottom = Math.max(bottom, child.getBottom()); |
| } |
| |
| if (left >= right || top >= bottom) { |
| // No valid area to draw in. |
| return; |
| } |
| |
| if (top > 0) { |
| mBackgroundFallback.setBounds(0, 0, width, top); |
| mBackgroundFallback.draw(c); |
| } |
| if (left > 0) { |
| mBackgroundFallback.setBounds(0, top, left, height); |
| mBackgroundFallback.draw(c); |
| } |
| if (right < width) { |
| mBackgroundFallback.setBounds(right, top, width, height); |
| mBackgroundFallback.draw(c); |
| } |
| if (bottom < height) { |
| mBackgroundFallback.setBounds(left, bottom, right, height); |
| mBackgroundFallback.draw(c); |
| } |
| } |
| } |