Android Vertical Viewpager，如 NewsInShorts 应用程序

Question

如何像在 NewsInShort 应用程序中一样在 android 中创建垂直视图寻呼机。 https://play.google.com/store/apps/details?id=com.nis.app

这个应用程序包含新闻提要，当我们向上滑动当前新闻时，下一条新闻会以动画形式出现，就像我将当前新闻向上滑动一点，然后下一条新闻就会以这种方式显示。 向下滑动也是如此。

我在 Github 上找到了一个库。
https://github.com/rharter/ViewPager-Android

但是这个库不提供像 NewsInShort App 这样的东西。

如果有人曾经创建过这样的视图或库，请告诉我。

谢谢。

Answer 1

虽然回答为时已晚，但它可以帮助其他想要创建动画（viewpager 转换器）的人，比如 inshorts 应用程序。

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() {
    setPageTransformer(true, new DepthPageTransformer());
    setOverScrollMode(OVER_SCROLL_NEVER);
}


/**
 * 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));
}

public class DepthPageTransformer implements ViewPager.PageTransformer {
    private static final float MIN_SCALE = 0.75f;

    public void transformPage(View view, float position) {
        int pageWidth = view.getWidth();

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

        } else if (position <= 0) { // [-1,0]
            // Use the default slide transition when moving to the left page
            view.setAlpha(1);
            view.setTranslationX(view.getWidth() * -position);

            //set Y position to swipe in from top
            float yPosition = position * view.getHeight();
            view.setTranslationY(yPosition);
            view.setScaleX(1);
            view.setScaleY(1);

        } else if (position <= 1) { // (0,1]
            // Fade the page out.
            view.setAlpha(1 - position);

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

            // Scale the page down (between MIN_SCALE and 1)
            float scaleFactor = MIN_SCALE
                    + (1 - MIN_SCALE) * (1 - Math.abs(position));
            view.setScaleX(scaleFactor);
            view.setScaleY(scaleFactor);

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

}

你需要在xml中使用VerticalViewPager

Answer 2

经过长时间的研究，我找到了解决方案。
对于 ViewPager，我们可以设置 pageTransformer 属性并可以分配自定义 Transformation。
我想要的转换是 DepthPageTransformer。以下是记录此转换的链接。
https://stuff.mit.edu/afs/sipb/project/android/docs/training/animation/screen-slide.html#depth-page

public class DepthPageTransformer implements ViewPager.PageTransformer {
    private static float MIN_SCALE = 0.75f;

    public void transformPage(View view, float position) {
        int pageWidth = view.getWidth();

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

        } else if (position <= 0) { // [-1,0]
            // Use the default slide transition when moving to the left page
            view.setAlpha(1);
            view.setTranslationX(0);
            view.setScaleX(1);
            view.setScaleY(1);

        } else if (position <= 1) { // (0,1]
            // Fade the page out.
            view.setAlpha(1 - position);

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

            // Scale the page down (between MIN_SCALE and 1)
            float scaleFactor = MIN_SCALE
                    + (1 - MIN_SCALE) * (1 - Math.abs(position));
            view.setScaleX(scaleFactor);
            view.setScaleY(scaleFactor);

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