/** * 可拖拽ImageView * Created by admin on 2017/2/21. */public class FloatingImageView extends ImageView{  public FloatingImageView(Context context) {    super(context);  }  public FloatingImageView(Context context, AttributeSet attrs) {    super(context, attrs);  }  public FloatingImageView(Context context, AttributeSet attrs, int defStyleAttr) {    super(context, attrs, defStyleAttr);  }  @TargetApi(Build.VERSION_CODES.LOLLIPOP)  public FloatingImageView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {    super(context, attrs, defStyleAttr, defStyleRes);  }  int startX;  int startY;  int left;  int top;  int[] temp = new int[]{ 0, 0 };  @Override  public boolean onTouchEvent(MotionEvent event) {    boolean isMove = false;    int x = (int) event.getRawX();    int y = (int) event.getRawY();    switch (event.getAction()){      case MotionEvent.ACTION_DOWN: // touch down so check if the        startX = x;        startY = y;        temp[0] = (int) event.getX();        temp[1] = y - getTop();        break;      case MotionEvent.ACTION_MOVE: // touch drag with the ball        left = x - temp[0];        top = y - temp[1];        if(left < 0){//控制左邊界不超出          left = 0;        }        layout(left, top, left + getWidth(),top + getHeight());//自由拖拽        break;      case MotionEvent.ACTION_UP:        if (Math.abs(x - startX) > 2 || Math.abs(y - startY) > 2){//判斷是否移動,再一定范圍內不算是移動，解決觸發事件沖突          //將最后拖拽的位置定下來，否則頁面刷新渲染后按鈕會自動回到初始位置          //注意父容器          RelativeLayout.LayoutParams lp = (RelativeLayout.LayoutParams) getLayoutParams();          lp.setMargins(left, top,0,0);          setLayoutParams(lp);          //確定是拖拽          isMove = true;         }        break;    }    return isMove ? true : super.onTouchEvent(event);   }}