2011.09.21——— android 动态壁纸开发

2011.09.21——— android 动态壁纸开发
参考： http://www.ophonesdn.com/article/show/278
resources/articles/live-wallpapers.html

自己做了一个非常简单的 只是想了解过程 源码见附件 步骤如下：

1、新建一个Android工程  然后进入工程的/res/文件夹，删除layout这个文件夹，当然里面的main.xml也会被删除的，对于Live Wallpaper来说传统的布局文件是不需要的。

2、在res下面新建一个xml文件夹 然后新建一个mylivewallpaper.xml 内容如下：

<?xml version="1.0" encoding="utf-8"?>
<wallpaper xmlns:android="http://schemas.android.com/apk/res/android"
	android:thumbnail="@drawable/icon"
/>

这里的android:thumbnail值得是你这个动态壁纸的小图标 会在你选着动态壁纸的时候出现 如下图：



这个可以自己选一个好看一点的

3、开始编写代码了  直接看吧

package com.lp.wallpaper;

import java.text.SimpleDateFormat;
import java.util.Date;

import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.os.Handler;
import android.service.wallpaper.WallpaperService;
import android.view.MotionEvent;
import android.view.SurfaceHolder;

public class MyWallpaper extends WallpaperService{
	private Handler handler = new Handler();
	
	
	
	@Override
	public void onCreate() {
		System.out.println("service onCreate");
		super.onCreate();
	}

	@Override
	public void onDestroy() {
		System.out.println("service onDestory");
		super.onDestroy();
	}

	@Override
	public Engine onCreateEngine() {
		System.out.println("service onCreateEngine");
		return new MyEngine();
	}
	
	private class MyEngine extends Engine{
		
		private float x = 200;
		private float y = 300;
		private Paint mPaint;
		private boolean mVisible = false;
		
		private Runnable drawThread = new Runnable() {
			public void run() {
				drawWallpaper();
			}
		};
		
		public MyEngine(){
			System.out.println("MyEngine");
			mPaint = new Paint();
			mPaint.setColor(Color.RED);
			mPaint.setAntiAlias(true);
			mPaint.setStrokeWidth(4);
			mPaint.setStyle(Paint.Style.STROKE);
			mPaint.setTextSize(24);
		}

		@Override
		public Bundle onCommand(String action, int x, int y, int z, Bundle extras, boolean resultRequested) {
			// TODO Auto-generated method stub
			System.out.println("onCommand");
			return super.onCommand(action, x, y, z, extras, resultRequested);
		}

		@Override
		public void onCreate(SurfaceHolder surfaceHolder) {
			System.out.println("onCreate");
			super.onCreate(surfaceHolder);
			//作用是使壁纸能响应touch event，默认是false
			setTouchEventsEnabled(true);
		}

		@Override
		public void onDestroy() {
			System.out.println("onDestroy");
			super.onDestroy();
			handler.removeCallbacks(drawThread);
		}

		@Override
		public void onOffsetsChanged(float xOffset, float yOffset, float xOffsetStep, float yOffsetStep, int xPixelOffset, int yPixelOffset) {
			// TODO Auto-generated method stub
			System.out.println("onoffsetsChanged");
			super.onOffsetsChanged(xOffset, yOffset, xOffsetStep, yOffsetStep, xPixelOffset, yPixelOffset);
		}
		
		@Override
        public void onVisibilityChanged(boolean visible) {
			System.out.println("onVisibilityChanged");
            mVisible = visible;
            if (visible) {
            	//开始
    			handler.postDelayed(drawThread, 50);
            } else {
                handler.removeCallbacks(drawThread);
            }
        }

		@Override
		public void onSurfaceChanged(SurfaceHolder holder, int format, int width, int height) {
			System.out.println("onSurfaceChanged");
			// TODO Auto-generated method stub
			super.onSurfaceChanged(holder, format, width, height);
		}

		@Override
		public void onSurfaceCreated(SurfaceHolder holder) {
			System.out.println("onSurfaceCreated");
			super.onSurfaceCreated(holder);
		}

		@Override
		public void onSurfaceDestroyed(SurfaceHolder holder) {
			System.out.println("onSurfaceDestoryed");
			// TODO Auto-generated method stub
			super.onSurfaceDestroyed(holder);
			handler.removeCallbacks(drawThread);
		}

		@Override
		public void onTouchEvent(MotionEvent event) {
			System.out.println("onTouchEvent");
			// TODO Auto-generated method stub
			super.onTouchEvent(event);
		}
		
		
		private void drawWallpaper() {
			
			SurfaceHolder holder = getSurfaceHolder();
			Canvas canvas = holder.lockCanvas();
			drawTime(canvas);
			holder.unlockCanvasAndPost(canvas);
			
			//循环执行
			handler.postDelayed(drawThread, 50);
		}

		private void drawTime(Canvas canvas) {
			Date date = new Date(System.currentTimeMillis());
			SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
			String dataStr = sdf.format(date);
			canvas.save();
			canvas.drawColor(0xff00ff00);
			canvas.drawText(dataStr, x, y, mPaint);
			canvas.restore();
		}
	}

}

实现的效果是一个动态改变的时间 如下图：



我们一一来解释：
onCreateEngine() ：

启动一个WallpaperService.Engine 这个engine才是负责绘制壁纸以及响应与用户交互事件的核心部件 这个方法也是必须要重写的 并且是WallpaperService和service的主要区别

onOffsetsChanged():

这个一般在几个屏幕滑动的时候调用 而且 当你拖动A屏幕向B屏幕过度时 会随着B屏幕的显示面积的变大或者变小一直调用这个方法

onVisibilityChanged()

这个是屏幕显示或者不显示的时候调用的 必须完全覆盖屏幕才会调用

onCommand()

可以给壁纸发送一些命令 让其执行

onTouchEvent()
处理壁纸的点击时间的

setTouchEventsEnabled(true)

作用是使壁纸能响应touch event，默认是false

其他的看名字应该就知道了 呵呵

这里也说下Engine的惯用写法吧

private class MyEngine extends Engine{
		//这里定义一个线程
		private Runnable drawThread = new Runnable() {
			public void run() {
				drawWallpaper();
			}
		};
		//构造方法里面 一般初始化Paint对象
		public MyEngine(){
			System.out.println("MyEngine");
			mPaint = new Paint();
			mPaint.setColor(Color.RED);
			mPaint.setAntiAlias(true);
			mPaint.setStrokeWidth(4);
			mPaint.setStyle(Paint.Style.STROKE);
			mPaint.setTextSize(24);
		}

                //这里 调用setTouchEventsEnabled(true);即可
		@Override
		public void onCreate(SurfaceHolder surfaceHolder) {
			System.out.println("onCreate");
			super.onCreate(surfaceHolder);
			//作用是使壁纸能响应touch event，默认是false
			setTouchEventsEnabled(true);
		}
                //取消callback
		@Override
		public void onDestroy() {
			System.out.println("onDestroy");
			super.onDestroy();
			handler.removeCallbacks(drawThread);
		}
                //当显示的时候 绑定callback 不显示时  取消callback		
		@Override
        public void onVisibilityChanged(boolean visible) {
			System.out.println("onVisibilityChanged");
            mVisible = visible;
            if (visible) {
            	//开始
    			handler.postDelayed(drawThread, 50);
            } else {
                handler.removeCallbacks(drawThread);
            }
        }

		@Override
		public void onSurfaceChanged(SurfaceHolder holder, int format, int width, int height) {
			System.out.println("onSurfaceChanged");
			// TODO Auto-generated method stub
			super.onSurfaceChanged(holder, format, width, height);
		}

		@Override
		public void onSurfaceCreated(SurfaceHolder holder) {
			System.out.println("onSurfaceCreated");
			super.onSurfaceCreated(holder);
		}
                 //取消callback
		@Override
		public void onSurfaceDestroyed(SurfaceHolder holder) {
			System.out.println("onSurfaceDestoryed");
			// TODO Auto-generated method stub
			super.onSurfaceDestroyed(holder);
			handler.removeCallbacks(drawThread);
		}
                //处理点击事件 比如说 点击时 出现水波等
		@Override
		public void onTouchEvent(MotionEvent event) {
			System.out.println("onTouchEvent");
			// TODO Auto-generated method stub
			super.onTouchEvent(event);
		}
		
		//得到surfaceholder和canvas 并调用核心处理方法
		private void drawWallpaper() {
			
			SurfaceHolder holder = getSurfaceHolder();
			Canvas canvas = holder.lockCanvas();
			drawTime(canvas);
			holder.unlockCanvasAndPost(canvas);
			
			//循环执行
			handler.postDelayed(drawThread, 50);
		}
                //核心处理方法
		private void drawTime(Canvas canvas) {
			
		}
	}

4、在AndroidManifes.xml里面注册service

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.lp.wallpaper">
    <uses-sdk android:minSdkVersion="7" />
    <uses-feature android:name="android.software.live_wallpaper" />

    <application 
	    android:icon="@drawable/icon" 
	    android:label="@string/app_name">
    
		<service 
			android:label="@string/app_name"
			android:name=".MyWallpaper"
			android:permission="android.permission.BIND_WALLPAPER">
			<intent-filter>
				<action android:name="android.service.wallpaper.WallpaperService" />  
			</intent-filter>
			<meta-data android:name="android.service.wallpaper" android:resource="@xml/mylivewallpaper" />	
		</service>

    </application>
</manifest>

除了

android:resource="@xml/mylivewallpaper"

是可以自己修改 其他的都是必须得 特别强调几个：

<uses-sdk android:minSdkVersion="7" />
<uses-feature android:name="android.software.live_wallpaper" />
android:permission="android.permission.BIND_WALLPAPER"

5、自己的一些关于方法执行顺序的测试信息：
当进入改壁纸的设置页面 但是还没有设置时
09-21 07:55:05.575: INFO/System.out(1337): service onCreate
09-21 07:55:05.614: INFO/System.out(1337): service onCreateEngine
09-21 07:55:05.634: INFO/System.out(1337): MyEngine
09-21 07:55:05.663: INFO/System.out(1337): onCreate
09-21 07:55:05.746: INFO/System.out(1337): onSurfaceCreated
09-21 07:55:05.753: INFO/System.out(1337): onSurfaceChanged
09-21 07:55:05.785: INFO/System.out(1337): onVisibilityChanged

当点击设置壁纸按钮后
09-21 07:55:19.434: INFO/System.out(1337): onTouchEvent
09-21 07:55:19.574: INFO/System.out(1337): onTouchEvent
09-21 07:55:20.283: INFO/System.out(1337): service onCreateEngine
09-21 07:55:20.294: INFO/System.out(1337): MyEngine
09-21 07:55:20.304: INFO/System.out(1337): onCreate
09-21 07:55:20.414: INFO/System.out(1337): onSurfaceCreated
09-21 07:55:20.424: INFO/System.out(1337): onSurfaceChanged
09-21 07:55:20.443: INFO/System.out(1337): onVisibilityChanged
09-21 07:55:20.443: INFO/System.out(1337): onoffsetsChanged
09-21 07:55:20.863: INFO/System.out(1337): onVisibilityChanged
09-21 07:55:21.305: INFO/System.out(1337): onSurfaceDestoryed
09-21 07:55:21.333: INFO/System.out(1337): onDestroy

在壁纸上面点击
09-21 07:55:34.654: INFO/System.out(1337): onTouchEvent
09-21 07:55:34.754: INFO/System.out(1337): onTouchEvent
09-21 07:55:34.754: INFO/System.out(1337): onCommand

启动其他程序 完全覆盖屏幕
09-21 07:56:03.855: INFO/System.out(1337): onTouchEvent
09-21 07:56:03.884: INFO/System.out(1337): onTouchEvent
09-21 07:56:04.494: INFO/System.out(1337): onVisibilityChanged

设置其他壁纸 代替自己的壁纸
09-21 07:56:34.893: INFO/System.out(1337): onSurfaceDestoryed
09-21 07:56:34.893: INFO/System.out(1337): onDestroy
09-21 07:56:34.953: INFO/System.out(1337): service onDestory


另：Engine的生命周期：