同时识别多个手势，需要设置手势代理
1. <UIGestureRecognizerDelegate>
2.- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
return YES;
}
原文：http://www.cnblogs.com/liuting-1204/p/6396535.html