android动态壁纸开发(能运行的)

       网上也有讲开发动态壁纸的博客，我在看书编写这个例子时，发现我编写的动态壁纸找不到，后来发现是没有将我编写的WallpaperService跑起来，而书上和有些博客照搬写到是不需要Activity的，我发现没有Activity的话，程序都跑不起。下面讲下我的做法:

第一步：编写LiveWallpaper类继承WallpaperService,代码如下：

public class LiveWallpaper extends WallpaperService{
    private Bitmap bitmap;
    //  实现动态壁纸必须要实现的抽象方法
    @Override
    public Engine onCreateEngine() {
        bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.me);
        return new MyEngine();
    }
    class MyEngine extends Engine{
        private boolean mVisible;
        //  记录当前用户动作发生的位置
        private float mTouchX = -1;
        private float mTouchY = -1;
        //  记录要绘制的矩形的数量
        private int count = 1;
        //  记录第一个矩形所需坐标变换的X、Y坐标的偏移
        private int originX = 50,originY = 50;
        //  定义画笔
        private Paint mPaint = new Paint();
        Handler mHandler = new Handler();
        private final Runnable drawTarget = new Runnable() {
            @Override
            public void run() {
                drawFrame();
            }
        };

        @Override
        public void onCreate(SurfaceHolder surfaceHolder) {
            super.onCreate(surfaceHolder);
            //  初始化画笔
            mPaint.setARGB(76,0,0,255);
            mPaint.setAntiAlias(true);
            mPaint.setStyle(Paint.Style.FILL);
            //  设置壁纸的触碰事件为true
            setTouchEventsEnabled(true);
        }

        @Override
        public void onVisibilityChanged(boolean visible) {
            super.onVisibilityChanged(visible);
            mVisible = visible;
            if(visible){
                drawFrame();
            }else{
                //  如果界面不可见，删除回调
                mHandler.removeCallbacks(drawTarget);
            }
        }

        @Override
        public void onOffsetsChanged(float xOffset, float yOffset, float xOffsetStep, float yOffsetStep, int xPixelOffset, int yPixelOffset) {
            super.onOffsetsChanged(xOffset, yOffset, xOffsetStep, yOffsetStep, xPixelOffset, yPixelOffset);
            drawFrame();
        }

        @Override
        public void onDestroy() {
            super.onDestroy();
            //  删除回调
            mHandler.removeCallbacks(drawTarget);
        }

        @Override
        public void onTouchEvent(MotionEvent event) {
            //   检测到滑动操作
            if(event.getAction() == MotionEvent.ACTION_MOVE){
                mTouchX = event.getX();
                mTouchY = event.getY();
            }else{
                mTouchX = -1;
                mTouchY = -1;
            }
            super.onTouchEvent(event);
        }

        private void drawFrame(){
            final SurfaceHolder holder = getSurfaceHolder();
            Canvas c = null;
            try{
               c = holder.lockCanvas();
               if(c != null){
                   c.drawColor(0xffffffff);
                   //  在触碰点绘制图像
                   drawTouchPoint(c);
                   mPaint.setAlpha(76);
                   c.translate(originX,originY);
                   //  采用循环绘制count个图形
                   for(int i = 0; i < count; i++){
                       c.translate(80,0);
                       c.scale(0.95f,0.95f);
                       c.rotate(20f);
                       c.drawRect(0,0,150,75,mPaint);
                   }
               }
            }finally {
                if(c != null){
                    holder.unlockCanvasAndPost(c);
                }
            }
            //  调度下一次重绘
            mHandler.removeCallbacks(drawTarget);
            if(mVisible){
                count++;
                if(count >= 50){
                    Random rand = new Random();
                    count  = 1;
                    originX += (rand.nextInt(60)-30);
                    originY += (rand.nextInt(60)-30);
                    try{
                        Thread.sleep(500);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                //  每隔0.1秒执行drawTarget一次
                mHandler.postDelayed(drawTarget,100);
            }
        }
        private void drawTouchPoint(Canvas c){
            if(mTouchX >= 0 && mTouchY >= 0){
                //  设置画笔的透明度
                mPaint.setAlpha(255);
                c.drawBitmap(bitmap,mTouchX,mTouchY,mPaint);
            }
        }
    }
}

第二步：在AndroidManifest.xml中进行态壁纸的service配置，代码如下：

android:permission="android.permission.BIND_WALLPAPER">
    
        
    
    

然后在res文件下下新建xml文件夹，在xml文件夹中建立livewallpaper.xml文件， livewallpaper.xml 文件中的代码如下:

第三步：在MainActivity中编写代码，运行WallpaperService,代码如下：

public class MainActivity extends Activity{
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Intent intent = new Intent(this,LiveWallpaper.class);
        //  启动设置的动态壁纸的Service
        startService(intent);
    }
}