安卓:垂直ViewPager [英] Android: Vertical ViewPager
问题描述
有 ViewPager
的实现,无法水平滚动,但垂直?
Is there an implementation of ViewPager
that does not scroll horizontally, but vertically?!
推荐答案
您可以使用<一个href="http://developer.android.com/reference/android/support/v4/view/ViewPager.PageTransformer.html">ViewPager.PageTransformer给垂直 ViewPager
的错觉。为了实现与垂直而非水平拖动滚动,你将不得不重写 ViewPager
的默认触摸事件和交换 MotionEvent $的坐标处理它们的C $ C>事先到,例如:
You can use a ViewPager.PageTransformer to give the illusion of a vertical ViewPager
. To achieve scrolling with a vertical instead of a horizontal drag you will have to override ViewPager
's default touch events and swap the coordinates of MotionEvent
s prior to handling them, e.g.:
/**
* Uses a combination of a PageTransformer and swapping X & Y coordinates
* of touch events to create the illusion of a vertically scrolling ViewPager.
*
* Requires API 11+
*
*/
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));
}
}
当然,您认为合适的,你可以调整这些设置。 最后应该是这样的:
Of course you can tweak these settings as you see fit. Ends up looking like this:
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