self.navigationController.interactivePopGestureRecognizer.enabled = YES;

self.navigationController.interactivePopGestureRecognizer.delegate = nil;

self.navigationController.interactivePopGestureRecognizer.enabled = YES ;

- (void)viewDidAppear:(BOOL)animated{
   self.navigationController.interactivePopGestureRecognizer.delegate = (id)self;
}

#pragma mark - UIGestureRecognizerDelegate
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer*)gestureRecognizer{
  //判断是否为rootViewController
  if (self.navigationController && self.navigationController.viewControllers.count == 1) {
    return NO;
  }
  return YES;
}

  UIBarButtonItem *item = [[UIBarButtonItem alloc]init];
  item.title = @"";
  self.navigationItem.backBarButtonItem = item;

- (void)viewWillDisappear:(BOOL)animated {
  [super viewWillDisappear:animated];
  //代理置空，否则会闪退
  if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
    self.navigationController.interactivePopGestureRecognizer.delegate = nil;
  }
}
- (void)viewDidAppear:(BOOL)animated { 
  [super viewDidAppear:animated]; 
  //开启iOS7的滑动返回效果 
  if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) { 
    //只有在二级页面生效 
    if ([self.navigationController.viewControllers count] == 2) { 
      self.navigationController.interactivePopGestureRecognizer.delegate = self; 
    } 
  } 
} 

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated { 
//开启滑动手势
  if ([navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
    navigationController.interactivePopGestureRecognizer.enabled = YES;
  }
} 

//在切换界面的过程中禁止滑动手势，避免界面卡死
if ([_currentNav respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
  _currentNav.interactivePopGestureRecognizer.enabled = NO;
}
[_currentNav pushViewController:viewController animated:YES];