Android实现桌面悬浮小火箭效果

public class RocketService extends Service {

   private WindowManager mWM;
   private View view;
   private int startX ;
   private int startY ;
   private LayoutParams params;

   @Override
   public IBinder onBind(Intent intent) {
      return null ;
   }

   @Override
   public void onCreate() {
      super .onCreate();
     System. out .println("服务创建。。。。" );
      mWM = (WindowManager) getSystemService(WINDOW_SERVICE );
      winWidth = mWM.getDefaultDisplay(). getWidth();
      winHeight = mWM .getDefaultDisplay().getHeight ();

      params = new WindowManager.LayoutParams();
      params. height = WindowManager.LayoutParams.WRAP_CONTENT ;
      params. width = WindowManager.LayoutParams.WRAP_CONTENT ;
      params. flags = WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
          | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE ;
      params. format = PixelFormat. TRANSLUCENT ;
      params. type = WindowManager.LayoutParams.TYPE_PHONE ;
      params. gravity = Gravity. LEFT + Gravity. TOP;

      view = LayoutInflater.from( this).inflate(R.layout. rocket , null );
      //拿到 imageview，设置帧动画
     ImageView ivRocket = (ImageView) view .findViewById(R.id. rocket);
     ivRocket.setImageResource(R.drawable. rocket );
     AnimationDrawable drawable = (AnimationDrawable) ivRocket.getDrawable();
     drawable.start();
      mWM.addView( view, params);

      // 设置view的触摸事件，让它可以被拖拽
      view.setOnTouchListener( new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
          switch (event.getAction()) {
          case MotionEvent. ACTION_DOWN:
             startX = ( int ) event.getRawX();
             startY = ( int ) event.getRawY();
             break ;
          case MotionEvent. ACTION_MOVE:
             int dx = (int ) (event.getRawX() - startX );
             int dy = (int ) (event.getRawY() - startY );
             // 更新浮窗位置
             params. x += dx;
             params. y += dy;

             // 限制窗口坐标不超过屏幕
             if (params .x < 0) {
               params. x = 0;
            }

             if (params .x > winWidth - view .getWidth()) {
               params. x = winWidth - view .getWidth();
            }

             if (params .y < 0) {
               params. y = 0;
            }

             if (params .y > winHeight - view .getHeight()) {
               params. y = winHeight - view .getHeight();
            }

             mWM.updateViewLayout( view, params );
             startX = ( int ) event.getRawX();
             startY = ( int ) event.getRawY();
             break ;
          case MotionEvent. ACTION_UP:
             // 手指抬起起，需要发射火箭，限定发射火箭的范围
             if (params .x > 0 && params. x < winWidth
                 && params. y > winHeight - 500) {
               sendRocket();
            }
             break ;
          }

          return true ;// 不再把事件传递给onClick处理
       }

     });
   }

   private Handler mHandler = new Handler() {
      @Override
      public void handleMessage(Message msg) {
          int y = msg.arg1 ;
          params. y = y;
          mWM.updateViewLayout( view, params);
     }
   };
   private int winWidth ;
   private int winHeight ;

   // 发射火箭
   private void sendRocket() {
      // 用子线程更新y轴
      new Thread(new Runnable() {

        @Override
        public void run() {
          int pos = 1000;
          for (int i=0; i <= 10; i++) {
               int y = pos-100*i;
               //休眠100ms发消息
               try {
                 Thread. sleep(100);
               } catch (InterruptedException e) {
                  // TODO Auto-generated catch block
                 e.printStackTrace();
               }

               Message msg = Message.obtain();
               msg. arg1 = y;
               mHandler.sendMessage(msg);
          }
       }
     }).start();
   }

   @Override
   public void onDestroy() {
      // TODO Auto-generated method stub
      super .onDestroy();
      if (mWM != null && view != null) {
        mWM.removeView( view);
        view = null ;
     }

   }
}