Called to process touch screen events.
You can override this to intercept all touch screen events before they are dispatched to the window.
Be sure to call this implementation for touch screen events that should be handled normally.
译文：
调用此方法来处理触摸屏事件。
您可以覆盖此拦截所有触摸屏事件，他们被分派到窗口之前。
一定要调用这个实现的，应该可以正常处理触摸屏事件。
| ev | The touch screen event. |
|---|
原文地址：http://blog.csdn.net/caiwenfeng_for_23/article/details/24797601
