ios - 在没有UINavigationController的情况下向navigationItem添加backBarButtonItem？

Question

我有一个UIViewController，我在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，只能添加leftBarButtonItem和rightBarButtonItem。因此，我尝试将 backBarButtonItem 添加到 Controller 代码中的 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 View 上仍然没有 backBarButtonItem？如何解决？

Answer 1

您必须实际设置 leftBarButtonItem，而不是 backBarButtonItem，并且只有在设置 self.hidesBackBarButtonItem 后才可以，如下所示:

- (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];
}