是否在沒有UINavigationController的情況下將backBarButtonItem添加到navigationItem？

Question

我有一個UIViewController，我在InterfaceBuilder中添加了一個NavigationItem來查看標題，我發現我無法將backBarButtonItem拖動到navigationItem上，只能添加leftBarButtonItem和rightBarButtonItem。 因此，我嘗試將backBarButtonItem添加到控制器代碼中的navigationItem元素中：

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

但是視圖上仍然沒有backBarButtonItem嗎？ 如何解決？

Answer 1

您必須實際設置leftBarButtonItem，而不是backBarButtonItem，只有在這樣設置self.hidesBackBarButtonItem之后才能設置：

- (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];
}