1 /* 2 * Copyright (C) 2008 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.example.android.apis.graphics; 18 19 import android.content.Context; 20 import android.graphics.*; 21 import android.os.Bundle; 22 import android.view.*; 23 24 public class Layers extends GraphicsActivity { 25 26 @Override onCreate(Bundle savedInstanceState)27 protected void onCreate(Bundle savedInstanceState) { 28 super.onCreate(savedInstanceState); 29 setContentView(new SampleView(this)); 30 } 31 32 private static class SampleView extends View { 33 private static final int LAYER_FLAGS = Canvas.MATRIX_SAVE_FLAG | 34 Canvas.CLIP_SAVE_FLAG | 35 Canvas.HAS_ALPHA_LAYER_SAVE_FLAG | 36 Canvas.FULL_COLOR_LAYER_SAVE_FLAG | 37 Canvas.CLIP_TO_LAYER_SAVE_FLAG; 38 39 private Paint mPaint; 40 SampleView(Context context)41 public SampleView(Context context) { 42 super(context); 43 setFocusable(true); 44 45 mPaint = new Paint(); 46 mPaint.setAntiAlias(true); 47 } 48 onDraw(Canvas canvas)49 @Override protected void onDraw(Canvas canvas) { 50 canvas.drawColor(Color.WHITE); 51 52 canvas.translate(10, 10); 53 54 canvas.saveLayerAlpha(0, 0, 200, 200, 0x88, LAYER_FLAGS); 55 56 mPaint.setColor(Color.RED); 57 canvas.drawCircle(75, 75, 75, mPaint); 58 mPaint.setColor(Color.BLUE); 59 canvas.drawCircle(125, 125, 75, mPaint); 60 61 canvas.restore(); 62 } 63 } 64 } 65 66