// 默认是YES 设置为NO左侧右滑手势就不可用了
self.interactivePopGestureRecognizer.enabled = YES;

-(void)viewDidAppear:(BOOL)animated {
  [super viewDidAppear:animated];
  self.navigationController.interactivePopGestureRecognizer.delegate = self;
}
#pragma mark - UIGestureRecognizerDelegate
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
  if (self.viewControllers.count <= 1) {
    return NO;
  }
  return YES;
}

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
  if (self.viewControllers.count > 0) {
    /* 不是栈底控制器的时候隐藏tabbar */
    viewController.hidesBottomBarWhenPushed = YES;
    // 设置左边的返回按钮leftBarButtonItem
    UIButton *backBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    backBtn.frame = CGRectMake(0, 0, 44, 44);
    backBtn.imageView.contentMode = UIViewContentModeCenter;
    backBtn.contentEdgeInsets = UIEdgeInsetsMake(0, 0, 0, 34);
    [backBtn setImage:[UIImage imageNamed:@"rrrr"] forState:UIControlStateNormal];
    [backBtn setImage:[UIImage imageNamed:@"rrrr"] forState:UIControlStateHighlighted];
    [backBtn addTarget: self action: @selector(back) forControlEvents: UIControlEventTouchUpInside];
    UIBarButtonItem *backBtnItem=[[UIBarButtonItem alloc]initWithCustomView:backBtn];
    viewController.navigationItem.leftBarButtonItem = backBtnItem;
// 此处改为设置backBarButtonItem 右滑手势可以用，但自定义按钮不展示！！
  }
  [super pushViewController:viewController animated:animated];
}

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
  if (self.viewControllers.count > 0) {
    /* 不是栈底控制器的时候隐藏tabbar */
    viewController.hidesBottomBarWhenPushed = YES;
  }
  [self.navigationBar setBackIndicatorImage:[UIImage imageNamed:@"rrrr"]];
  [self.navigationBar setBackIndicatorTransitionMaskImage:[UIImage imageNamed:@"rrrr"]];
  UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];
  self.navigationItem.backBarButtonItem = backItem;
  [super pushViewController:viewController animated:animated];
}

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
  if (self.viewControllers.count > 0) {
    /* 不是栈底控制器的时候隐藏tabbar */
    viewController.hidesBottomBarWhenPushed = YES;
    [self.navigationBar setBackIndicatorImage:[UIImage imageNamed:@"rrrr"]];
    [self.navigationBar setBackIndicatorTransitionMaskImage:[UIImage imageNamed:@"rrrr"]];
    UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];
    self.navigationItem.leftBarButtonItem = backItem;
  }
  [super pushViewController:viewController animated:animated];
}

- (void)viewDidLoad {
  [super viewDidLoad];
  // 设置左边的返回按钮
  UIButton *backBtn = [UIButton buttonWithType:UIButtonTypeCustom];
  backBtn.frame = CGRectMake(0, 0, 44, 44);
  backBtn.imageView.contentMode = UIViewContentModeCenter;
  backBtn.contentEdgeInsets = UIEdgeInsetsMake(0, 0, 0, 34);
  [backBtn setImage:[UIImage imageNamed:@"rrrr"] forState:UIControlStateNormal];
  [backBtn setImage:[UIImage imageNamed:@"rrrr"] forState:UIControlStateHighlighted];
  [backBtn addTarget: self action: @selector(back) forControlEvents: UIControlEventTouchUpInside];
  backBtn.backgroundColor = [UIColor redColor];
  
  [self.navigationController.navigationBar setBackIndicatorImage:[UIImage imageNamed:@"rrrr"]];
  [self.navigationController.navigationBar setBackIndicatorTransitionMaskImage:[UIImage imageNamed:@"rrrr"]];
  UIBarButtonItem *backBtnItem=[[UIBarButtonItem alloc]initWithCustomView:backBtn];
  backBtnItem.title = @"";
  self.navigationItem.backBarButtonItem = backBtnItem;
  }