Android实现让图片在屏幕上任意移动的方法(拖拽功能)

public class DragExampleActivity extends Activity {  Bitmap mBitmap;  /** Called when the activity is first created. */  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon);    setContentView(new DragView(this));  }  @Override  protected void onDestroy()  {    super.onDestroy();    if(null != mBitmap) {      mBitmap.recycle();      mBitmap = null;    }  }  private class DragView extends View {    private int mMotionX = 0;    private int mMotionY = 0;    private Paint paint;    public DragView(Context context)    {      super(context);      paint = new Paint();    }    @Override    public void draw(Canvas canvas)    {      super.draw(canvas);      canvas.drawBitmap(mBitmap, mMotionX, mMotionY, paint);    }    @Override    public boolean onTouchEvent(MotionEvent ev)    {      if(ev.getAction() == MotionEvent.ACTION_DOWN)      {        mMotionX = (int) ev.getX();        mMotionY = (int) ev.getY();        invalidate();        return true;      }else {        return super.onTouchEvent(ev);      }    }  }}