自定义navigationItem.leftBarButtonItem后,系统默认的手势滑动失效解决方案

LeftBarButtonItemGesture.m

- (void)viewDidLoad {  
    [super viewDidLoad];  
    __weak typeof (self) weakSelf = self;  
    if ([self respondsToSelector:@selector(interactivePopGestureRecognizer)]) {  
        self.interactivePopGestureRecognizer.delegate = weakSelf;  
    }  
}  
#pragma mark - UIGestureRecognizerDelegate  
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {  
    if (self.viewControllers.count < 3) {  
        return NO;  
    }  
    return YES;  
}