RecyclerViewBackedScrollView.java 文件源码

@Override
public boolean onTouchEvent(MotionEvent ev) {
    int action = ev.getAction() & MotionEvent.ACTION_MASK;
    if (action == MotionEvent.ACTION_UP && mDragging) {
        mDragging = false;
        mVelocityHelper.calculateVelocity(ev);
        getReactContext().getNativeModule(UIManagerModule.class).getEventDispatcher()
                .dispatchEvent(ScrollEvent.obtain(
                        getId(),
                        ScrollEventType.END_DRAG,
                        0, /* offsetX = 0, horizontal scrolling only */
                        computeVerticalScrollOffset(),
                        mVelocityHelper.getXVelocity(),
                        mVelocityHelper.getYVelocity(),
                        getWidth(),
                        computeVerticalScrollRange(),
                        getWidth(),
                        getHeight()));
    }
    return super.onTouchEvent(ev);
}