- (void)addBackItemWithAction:(SEL)action {
  if (IOS7_OR_LATER) {
    UIBarButtonItem *returnButtonItem = [[UIBarButtonItem alloc] init];
    returnButtonItem.title = @"返回";
    self.navigationItem.backBarButtonItem = returnButtonItem;
  } else {
    // 设置返回按钮的文本
    UIBarButtonItem *backButton = [[UIBarButtonItem alloc]
                                   initWithTitle:@"返回"
                                   style:UIBarButtonItemStylePlain target:nil action:nil];
    [self.navigationItem setBackBarButtonItem:backButton];
    
    // 设置返回按钮的背景图片
    UIImage *img = [UIImage imageNamed:@"ic_back_nor"];
    img = [img resizableImageWithCapInsets:UIEdgeInsetsMake(0, 18, 0, 0)];
    [[UIBarButtonItem appearance] setBackButtonBackgroundImage:img
                                                      forState:UIControlStateNormal
                                                    barMetrics:UIBarMetricsDefault];
    // 设置文本与图片的偏移量
    [[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(5, 0)
                                                         forBarMetrics:UIBarMetricsDefault];
    // 设置文本的属性
    NSDictionary *attributes = @{UITextAttributeFont:[UIFont systemFontOfSize:16],
                                 UITextAttributeTextShadowOffset:[NSValue valueWithUIOffset:UIOffsetZero]};
    [[UIBarButtonItem appearance] setTitleTextAttributes:attributes forState:UIControlStateNormal];
  }
  return;
}