ios - 是否在没有UINavigationController的情况下将backBarButtonItem添加到navigationItem？

我有一个UIViewController，并在InterfaceBuilder中添加了一个NavigationItem来查看标题，我发现我无法将backBarButtonItem拖动到navigationItem上，只能添加leftBarButtonItem和rightBarButtonItem。因此，我尝试在控制器代码中将backBarButtonItem添加到navigationItem元素：

- (void)viewWillAppear:(BOOL)animated {
   UIBarButtonItem *_backButton = [[UIBarButtonItem alloc] initWithTitle:@"Back"   style:UIBarButtonItemStyleDone target:nil action:nil];
   self.myNavigationItem.backBarButtonItem = _backButton;
  [_backButton release];
}

但是视图上仍然没有backBarButtonItem吗？如何解决？

最佳答案

您实际上必须设置leftBarButtonItem，而不是backBarButtonItem，只有在设置self.hidesBackBarButtonItem之后才这样设置：

- (void)viewWillAppear:(BOOL)animated {
 UIBarButtonItem *_backButton = [[UIBarButtonItem alloc] initWithTitle:@"Back"   style:UIBarButtonItemStyleDone target:nil action:nil];
    self.navigationItem.hidesBackButtonItem = YES;
     self.myNavigationItem.leftBarButtonItem = _backButton;
    [_backButton release];
}