- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event   {
   if (point.x < location.x) { // location.x为系统的某个点的x
     return nil;
   } else {
     return [super hitTest:point withEvent:event];
   }
}

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {

    if ([self panBack:gestureRecognizer]) {
       return YES;
    }
    return NO;

 }


- (BOOL)panBack:(UIGestureRecognizer *)gestureRecognizer {

  if (gestureRecognizer == self.panGestureRecognizer) {
     UIPanGestureRecognizer *pan = (UIPanGestureRecognizer *)gestureRecognizer;
     CGPoint point = [pan translationInView:self];
     UIGestureRecognizerState state = gestureRecognizer.state;
     if (UIGestureRecognizerStateBegan == state || UIGestureRecognizerStatePossible == state) {
       CGPoint location = [gestureRecognizer locationInView:self];
       if (point.x > 0 && location.x < “这个自己设定" && self.contentOffset.x <= 0) {
          return YES;
       }
     }
   }
   return NO;

}

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {

  if ([self panBack:gestureRecognizer]) {
    return NO;
  }
  return YES;

}

 -(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer 
 { 
   // 首先判断otherGestureRecognizer是不是系统pop手势 
   if ([otherGestureRecognizer.view isKindOfClass:NSClassFromString(@"UILayoutContainerView")]) { 
     // 再判断系统手势的state是began还是fail，同时判断scrollView的位置是不是正好在最左边 
     if (otherGestureRecognizer.state == UIGestureRecognizerStateBegan && self.contentOffset.x == 0) { 
       return YES; 
     } 
   } 

   return NO; 
}