Android custom scrollview achieves rebound effect

//Intercept: implement parent view intercept child view//Whether the interception is successful depends on the return value of the method.  Return value true: Intercept successfully.  On the contrary, the interception failedprivate int lastY;//The coordinate position of the last y-axis operation    private Rect normal = new Rect();// Used to record the left, upper, right, and lower critical state    private boolean isFinishAnimation = true;//Whether the animation ends    private int lastX, downX, downY;
    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        boolean isIntercept = false;
        int eventX = (int) ();
        int eventY = (int) ();
        switch (()) {
            case MotionEvent.ACTION_DOWN:
                lastX = downX = eventX;
                lastY = downY = eventY;
                break;
            case MotionEvent.ACTION_MOVE:
                //Get the horizontal and vertical movement distance                int absX = (eventX - downX);
                int absY = (eventY - downY);
                if(absY > absX && absY >= dp2px(10)){
                    isIntercept = true;//Execute interception                }
                lastX = eventX;
                lastY = eventY;
                break;
        }
        return isIntercept;
    }

//Get subview    @Override
    protected void onFinishInflate() {
        ();
        if (getChildCount() > 0) {
            childView = getChildAt(0);
        }
    }

private boolean isNeedMove() {
        int childMeasuredHeight = ();//Get the height of the subview        int scrollViewMeasuredHeight = ();//Get the height of the layout        ("TAG", "childMeasuredHeight = " + childMeasuredHeight);
        ("TAG", "scrollViewMeasuredHeight = " + scrollViewMeasuredHeight);
        int dy = childMeasuredHeight - scrollViewMeasuredHeight;//dy >= 0
        int scrollY = ();//Get the user's offset in the y-axis direction (top + bottom -)        if (scrollY <= 0 || scrollY >= dy) {
            return true;// Handle it in the way we customize MyScrollView        }
        //Others that are within the critical range will return false.  That means that it is still processed in the ScrollView method        return false;
    }

//Discern whether flat-moving painting needs to be performed    private boolean isNeedAnimation() {
        return !();
    }

@Override
    public boolean onTouchEvent(MotionEvent ev) {
        if (childView == null || !isFinishAnimation) {
            return (ev);
        }
        int eventY = (int) ();//Get the current y-axis coordinate        switch (()) {
            case MotionEvent.ACTION_DOWN:
                lastY = eventY;
                break;
            case MotionEvent.ACTION_MOVE:
                int dy = eventY - lastY;//Small amount of movement                if (isNeedMove()) {
                    if (()) {
                        //The left, upper, right, and lower critical state of childView is recorded.                        ((), (), (), ());
                    }
                    //Re-layout                    ((), () + dy / 2, (), () + dy / 2);
                }
                lastY = eventY;//Reassign value                break;
            case MotionEvent.ACTION_UP:
                if (isNeedAnimation()) {
                    //Use flat moving painting                    int translateY = () - ;
                    TranslateAnimation translateAnimation = new TranslateAnimation(0, 0, 0, -translateY);
                    (200);
//          (true);// Stay at the final position                    (new () {
                        @Override
                        public void onAnimationStart(Animation animation) {
                            isFinishAnimation = false;
                        }
                        @Override
                        public void onAnimationEnd(Animation animation) {
                            isFinishAnimation = true;
                            ();//Clear the animation                            //Re-layout                            (, , , );
                            //Clear normal data                            ();
                        }
                        @Override
                        public void onAnimationRepeat(Animation animation) {
                        }
                    });
                    //Start the animation                    (translateAnimation);
                }
                break;
        }
        return (ev);
    }