Android 如何修复添加了填充的VerticalViewPage？

我有一个VerticalViewPage，工作起来很有魅力：

import android.content.Context;
    import android.support.v4.view.ViewPager;
    import android.util.AttributeSet;
    import android.view.MotionEvent;
    import android.view.View;


    public class VerticalViewPager extends ViewPager {

        public VerticalViewPager(Context context) {
            super(context);
            init();
        }

        public VerticalViewPager(Context context, AttributeSet attrs) {
            super(context, attrs);
            init();
        }

        private void init() {
            // The majority of the magic happens here
            setPageTransformer(true, new VerticalPageTransformer());
            // The easiest way to get rid of the overscroll drawing that happens on the left and right
            setOverScrollMode(OVER_SCROLL_NEVER);
        }

        private class VerticalPageTransformer implements ViewPager.PageTransformer {

            @Override
            public void transformPage(View view, float position) {

                if (position < -1) { // [-Infinity,-1)
                    // This page is way off-screen to the left.
                    view.setAlpha(0);

                } else if (position <= 1) { // [-1,1]
                    view.setAlpha(1);

                    // Counteract the default slide transition
                    view.setTranslationX(view.getWidth() * -position);

                    //set Y position to swipe in from top
                    float yPosition = position * view.getHeight();
                    view.setTranslationY(yPosition);

                } else { // (1,+Infinity]
                    // This page is way off-screen to the right.
                    view.setAlpha(0);
                }
            }
        }

        /**
         * Swaps the X and Y coordinates of your touch event.
         */
        private MotionEvent swapXY(MotionEvent ev) {
            float width = getWidth();
            float height = getHeight();

            float newX = (ev.getY() / height) * width;
            float newY = (ev.getX() / width) * height;

            ev.setLocation(newX, newY);

            return ev;
        }

        @Override
        public boolean onInterceptTouchEvent(MotionEvent ev){
            boolean intercepted = super.onInterceptTouchEvent(swapXY(ev));
            swapXY(ev); // return touch coordinates to original reference frame for any child views
            return intercepted;
        }

        @Override
        public boolean onTouchEvent(MotionEvent ev) {
            return super.onTouchEvent(swapXY(ev));
        }

    }

视图进入屏幕的下角（基本上脱离屏幕），我不知道如何修改代码中的transformPage来修复此问题，请帮助

我的布局文件符合要求：

发布布局文件请检查编辑发布布局文件请检查编辑

android:paddingEnd 40dp               
android:paddingLeft 40dp                
android:paddingRight 40dp

android:paddingStart 40dp