- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    [self showBackBtn:YES];

}

- (void)returnClick {

    if ([[self.navigationController viewControllers] count] ==1) {
        [self dismissViewControllerAnimated:YES completion:^{

        }];
    }else{
        [self.navigationController popViewControllerAnimated:YES];
    }

}

#pragma mark - 显示返回按钮

- (void)showBackBtn:(BOOL)show {

    if (self.navigationItem)
    {
        if (show)
        {
            UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"title_bar_back"] style:UIBarButtonItemStyleDone target:self action:@selector(returnClick)];
            self.navigationItem.leftBarButtonItem = item;
        }
    }

}