| /* |
| * 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.annotation.Nullable; |
| 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 @Nullable Drawable getDrawable() { |
| return mBackgroundFallback; |
| } |
| |
| 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. |
| * @param coveringView1 A potentially opaque view drawn atop the content |
| * @param coveringView2 A potentially opaque view drawn atop the content |
| */ |
| public void draw(ViewGroup boundsView, ViewGroup root, Canvas c, View content, |
| View coveringView1, View coveringView2) { |
| if (!hasFallback()) { |
| return; |
| } |
| |
| // Draw the fallback in the padding. |
| final int width = boundsView.getWidth(); |
| final int height = boundsView.getHeight(); |
| |
| final int rootOffsetX = root.getLeft(); |
| final int rootOffsetY = root.getTop(); |
| |
| 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 || !isOpaque(childBg)) { |
| // 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, rootOffsetX + child.getLeft()); |
| top = Math.min(top, rootOffsetY + child.getTop()); |
| right = Math.max(right, rootOffsetX + child.getRight()); |
| bottom = Math.max(bottom, rootOffsetY + child.getBottom()); |
| } |
| |
| // If one of the bar backgrounds is a solid color and covers the entire padding on a side |
| // we can drop that padding. |
| boolean eachBarCoversTopInY = true; |
| for (int i = 0; i < 2; i++) { |
| View v = (i == 0) ? coveringView1 : coveringView2; |
| if (v == null || v.getVisibility() != View.VISIBLE |
| || v.getAlpha() != 1f || !isOpaque(v.getBackground())) { |
| eachBarCoversTopInY = false; |
| continue; |
| } |
| |
| // Bar covers entire left padding |
| if (v.getTop() <= 0 && v.getBottom() >= height |
| && v.getLeft() <= 0 && v.getRight() >= left) { |
| left = 0; |
| } |
| // Bar covers entire right padding |
| if (v.getTop() <= 0 && v.getBottom() >= height |
| && v.getLeft() <= right && v.getRight() >= width) { |
| right = width; |
| } |
| // Bar covers entire top padding |
| if (v.getTop() <= 0 && v.getBottom() >= top |
| && v.getLeft() <= 0 && v.getRight() >= width) { |
| top = 0; |
| } |
| // Bar covers entire bottom padding |
| if (v.getTop() <= bottom && v.getBottom() >= height |
| && v.getLeft() <= 0 && v.getRight() >= width) { |
| bottom = height; |
| } |
| |
| eachBarCoversTopInY &= v.getTop() <= 0 && v.getBottom() >= top; |
| } |
| |
| // Special case: Sometimes, both covering views together may cover the top inset, but |
| // neither does on its own. |
| if (eachBarCoversTopInY && (viewsCoverEntireWidth(coveringView1, coveringView2, width) |
| || viewsCoverEntireWidth(coveringView2, coveringView1, width))) { |
| top = 0; |
| } |
| |
| 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); |
| } |
| } |
| |
| private boolean isOpaque(Drawable childBg) { |
| return childBg != null && childBg.getOpacity() == PixelFormat.OPAQUE; |
| } |
| |
| /** |
| * Returns true if {@code view1} starts before or on {@code 0} and extends at least |
| * up to {@code view2}, and that view extends at least to {@code width}. |
| * |
| * @param view1 the first view to check if it covers the width |
| * @param view2 the second view to check if it covers the width |
| * @param width the width to check for |
| * @return returns true if both views together cover the entire width (and view1 is to the left |
| * of view2) |
| */ |
| private boolean viewsCoverEntireWidth(View view1, View view2, int width) { |
| return view1.getLeft() <= 0 |
| && view1.getRight() >= view2.getLeft() |
| && view2.getRight() >= width; |
| } |
| } |