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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.internal.policy.impl;
     18 
     19 import android.content.Context;
     20 import android.graphics.Canvas;
     21 import android.graphics.Rect;
     22 import android.graphics.drawable.Drawable;
     23 import android.util.AttributeSet;
     24 import android.util.Log;
     25 import android.view.Gravity;
     26 import android.view.View;
     27 import android.widget.LinearLayout;
     28 
     29 /**
     30  * A vertical linear layout.  However, instead of drawing the background
     31  * behnd the items, it draws the background outside the items based on the
     32  * padding.  If there isn't enough room to draw both, it clips the background
     33  * instead of the contents.
     34  */
     35 public class RecentApplicationsBackground extends LinearLayout {
     36     private static final String TAG = "RecentApplicationsBackground";
     37 
     38     private boolean mBackgroundSizeChanged;
     39     private Drawable mBackground;
     40     private Rect mTmp0 = new Rect();
     41     private Rect mTmp1 = new Rect();
     42 
     43     public RecentApplicationsBackground(Context context) {
     44         this(context, null);
     45         init();
     46     }
     47 
     48     public RecentApplicationsBackground(Context context, AttributeSet attrs) {
     49         super(context, attrs);
     50         init();
     51     }
     52 
     53     private void init() {
     54         mBackground = getBackground();
     55         setBackgroundDrawable(null);
     56         setPadding(0, 0, 0, 0);
     57         setGravity(Gravity.CENTER);
     58     }
     59 
     60     @Override
     61     protected boolean setFrame(int left, int top, int right, int bottom) {
     62         setWillNotDraw(false);
     63         if (mLeft != left || mRight != right || mTop != top || mBottom != bottom) {
     64             mBackgroundSizeChanged = true;
     65         }
     66         return super.setFrame(left, top, right, bottom);
     67     }
     68 
     69     @Override
     70     protected boolean verifyDrawable(Drawable who) {
     71         return who == mBackground || super.verifyDrawable(who);
     72     }
     73 
     74     @Override
     75     protected void drawableStateChanged() {
     76         Drawable d = mBackground;
     77         if (d != null && d.isStateful()) {
     78             d.setState(getDrawableState());
     79         }
     80         super.drawableStateChanged();
     81     }
     82 
     83     @Override
     84     public void draw(Canvas canvas) {
     85         final Drawable background = mBackground;
     86         if (background != null) {
     87             if (mBackgroundSizeChanged) {
     88                 mBackgroundSizeChanged = false;
     89                 Rect chld = mTmp0;
     90                 Rect bkg = mTmp1;
     91                 mBackground.getPadding(bkg);
     92                 getChildBounds(chld);
     93                 // This doesn't clamp to this view's bounds, which is what we want,
     94                 // so that the drawing is clipped.
     95                 final int top = chld.top - bkg.top;
     96                 final int bottom = chld.bottom + bkg.bottom;
     97                 // The background here is a gradient that wants to
     98                 // extend the full width of the screen (whatever that
     99                 // may be).
    100                 int left, right;
    101                 if (false) {
    102                     // This limits the width of the drawable.
    103                     left = chld.left - bkg.left;
    104                     right = chld.right + bkg.right;
    105                 } else {
    106                     // This expands it to full width.
    107                     left = 0;
    108                     right = getRight();
    109                 }
    110                 background.setBounds(left, top, right, bottom);
    111             }
    112         }
    113         mBackground.draw(canvas);
    114 
    115         if (false) {
    116             android.graphics.Paint p = new android.graphics.Paint();
    117             p.setColor(0x88ffff00);
    118             canvas.drawRect(background.getBounds(), p);
    119         }
    120         canvas.drawARGB((int)(0.75*0xff), 0, 0, 0);
    121 
    122         super.draw(canvas);
    123     }
    124 
    125     @Override
    126     protected void onAttachedToWindow() {
    127         super.onAttachedToWindow();
    128         mBackground.setCallback(this);
    129         setWillNotDraw(false);
    130     }
    131 
    132     @Override
    133     protected void onDetachedFromWindow() {
    134         super.onDetachedFromWindow();
    135         mBackground.setCallback(null);
    136     }
    137 
    138     private void getChildBounds(Rect r) {
    139         r.left = r.top = Integer.MAX_VALUE;
    140         r.bottom = r.right = Integer.MIN_VALUE;
    141         final int N = getChildCount();
    142         for (int i=0; i<N; i++) {
    143             View v = getChildAt(i);
    144             if (v.getVisibility() == View.VISIBLE) {
    145                 r.left = Math.min(r.left, v.getLeft());
    146                 r.top = Math.min(r.top, v.getTop());
    147                 r.right = Math.max(r.right, v.getRight());
    148                 r.bottom = Math.max(r.bottom, v.getBottom());
    149             }
    150         }
    151     }
    152 }
    153