Android片段中的手势检测

Question

我的手势检测器代码：它是所有简单的预定义代码

private final GestureDetector.SimpleOnGestureListener mGestureListener
        = new GestureDetector.SimpleOnGestureListener() {

    @Override
    public boolean onDown(MotionEvent e) {ViewCompat.postInvalidateOnAnimation(FractionalLinearLayout.this);
        return true;
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2,
                            float distanceX, float distanceY) {
        /**
         * Pixel offset is the offset in screen pixels, while viewport offset is the
         * offset within the current viewport. For additional information on surface sizes
         * and pixel offsets, see the docs for {@link computeScrollSurfaceSize()}. For
         * additional information about the viewport, see the comments for
         * {@link mCurrentViewport}.
         */

        Log.d("Testing Scroll", ""+distanceY);

        if(mParentView != null && mParentView.getId() == R.id.container && (distanceY>10 || distanceY<-10)){
            mParentView.scrollBy(0, (int)distanceY);
        }
        ViewCompat.postInvalidateOnAnimation(FractionalLinearLayout.this);

        return true;
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        mScroller.fling(getScrollX(), getScrollY(),
                -(int) velocityX, -(int) velocityX, 0, 0, 0, 0);
        ViewCompat.postInvalidateOnAnimation(FractionalLinearLayout.this);
        return true;
    }
};

mParentView 是此布局的parentView 我的输出动画采用视频格式：Jaggy Scrolling

滚动时是什么导致这种锯齿状？