向上滑动的ViewPager

也是在其他帖子看到的，记录下来。感谢万能的网络。

第一步 自定义view

/**
 * 竖向的ViewPager
 * Created by zh on 2018/4/27.
 */

public class VerticalViewPager extends ViewPager{
    private boolean isVertical = false;

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

    public VerticalViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
        initIsVertical(attrs, 0);
        init();
    }

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

    private void initIsVertical(AttributeSet attrs, int defStyle){
        final TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.MyViewPager, defStyle, 0);
        isVertical = a.getBoolean(R.styleable.MyViewPager_isVertical, false);
        System.out.println("isVertical=>" + isVertical);
        a.recycle();
    }


    private void init() {
        if(isVertical){
            // 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){
        if (isVertical) {
            boolean intercepted = super.onInterceptTouchEvent(swapXY(ev));
            swapXY(ev); // return touch coordinates to original reference frame for any child views
            return intercepted;
        }else {
            return super.onInterceptTouchEvent(ev);
        }
    }

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

第二步 在attr.xml中

使用：

其他和正常的viewpager一样了

再加一点，当滑动到最后一页后再向后滑动自动关闭功能

     vp.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageSelected(int arg0) {
                // arg0 确定到那页在改变 执行一次
            }
            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
            }
            @Override
            public void onPageScrollStateChanged(int arg0) {
                switch (arg0) {
                    case ViewPager.SCROLL_STATE_DRAGGING:
                        misScrolled = false;
                        break;
                    case ViewPager.SCROLL_STATE_SETTLING:
                        misScrolled = true;
                        break;
                    case ViewPager.SCROLL_STATE_IDLE:
                        if (vp.getCurrentItem() == vp.getAdapter().getCount() - 1 && !misScrolled) {
                            // 已经是最后一页
                            finish();
                        }
                        if (vp.getCurrentItem() == 0 && !misScrolled) {
                            // 已经是第一页"
                        }
                        misScrolled = true;
                        break;
                }
            }
        });