將UIBarButtonItem添加到推送到UINavigation控制器上的UIViewController

Question

我試圖將UIViewController推送到導航控制器上，然後將UIBarButtonItem添加到導航欄中，以便我可以使用它來顯示倒數計時器。

UINavigationController *navController = [[Session sharedInstance] getNavigationController]; 
GamePlayViewController *gameController = [[GamePlayViewController alloc] initWithNibName:@"GamePlayViewController" bundle:nil ]; 

UIBarButtonItem *timerBtn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil]; 

gameController.navigationItem.rightBarButtonItems = [NSArray arrayWithObjects:timerBtn, nil]; 

[navController pushViewController:gameController animated:YES]; 

當我使用上面的代碼不起作用。我也嘗試從控制器本身的ViewDidload方法做到這一點，但沒有骰子。我甚至嘗試使用rightBarButtonItem卻得到一個錯誤，說明

"to uncaught exception 'NSInvalidArgumentException', reason: 'Fixed and flexible space items not allowed as individual navigation bar button item. Please use the leftBarButtonItems (that's plural) property.' 
*** First throw call stack:" 




UIBarButtonItem *timerBtn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil]; 

self.navigationItem.rightBarButtonItem = timerBtn; 

Answer 1

如果你去IB並嘗試添加一個靈活的空間或固定的空間，你會看到這兩個對象，指出這2只能在細節被添加到正在添加到UIToolBar的UIBarButtonItem中，而不是添加到導航欄！

因此，我建議你改變你的代碼下面下手：

UIBarButtonItem *timerBtn = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonItemStylePlain target:nil action:nil];