先简单的贴下代码，回头讲解一下原理。
```
-(BOOL)gestureRecognizer:(UIGestureRecognizer*)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer*)otherGestureRecognizer{
if([gestureRecognizerisKindOfClass:[UIPanGestureRecognizer class]]) {
UIPanGestureRecognizer *panGes = (UIPanGestureRecognizer*)gestureRecognizer;
CGPointv = [panGesvelocityInView:self];
if(fabs(v.y)>fabs(v.x)) {
returnYES;
}
}
return NO;
}
```
