setRightBarButtonItems不起作用

Question

我想在UINavigationBar的右邊有兩個按鈕。 以下是源代碼。 沒有錯誤，但也沒有按鈕。 它是一個UIViewController ，而不是UINavigationViewController

let buttonEdit: UIButton = UIButton.buttonWithType(UIButtonType.Custom) as! UIButton
buttonEdit.frame = CGRectMake(0, 0, 40, 40)
buttonEdit.setImage(UIImage(named:"me44.png"), forState: UIControlState.Normal)
buttonEdit.addTarget(self, action: "rightNavItemEditClick:", forControlEvents: UIControlEvents.TouchUpInside)
var rightBarButtonItemEdit: UIBarButtonItem = UIBarButtonItem(customView: buttonEdit)

let buttonDelete: UIButton = UIButton.buttonWithType(UIButtonType.Custom) as! UIButton
buttonDelete.frame = CGRectMake(0, 0, 40, 40)
buttonDelete.setImage(UIImage(named:"me44.png"), forState: UIControlState.Normal)
buttonDelete.addTarget(self, action: "rightNavItemDeleteClick:", forControlEvents: UIControlEvents.TouchUpInside)

var rightBarButtonItemDelete: UIBarButtonItem = UIBarButtonItem(customView: buttonDelete)

// add multiple right bar button items       
self.navigationController?.navigationItem.setRightBarButtonItems([rightBarButtonItemDelete, rightBarButtonItemEdit] as [AnyObject], animated: true)

//I also tried code below no luck either
self.navigationItem.setRightBarButtonItems([rightBarButtonItemDelete, rightBarButtonItemEdit] as [AnyObject], animated: true)

Answer 1

這段代碼錯了：

self.navigationController?.navigationItem.setRightBarButtonItems(
    [rightBarButtonItemDelete, rightBarButtonItemEdit] as [AnyObject], animated: true)

您沒有設置導航控制器的navigationItem ; 你設置你的 navigationItem 。 而且， [AnyObject]事情是不必要的。 所以：

self.navigationItem.setRightBarButtonItems(
    [rightBarButtonItemDelete, rightBarButtonItemEdit], animated: true)

但請注意，僅當您的視圖控制器是UINavigationController的子級時才有效。 設置視圖控制器的navigationItem僅在該情況下自動填充導航欄。 如果您不處於這種情況 - 即，如果您的界面中只有一個“松散”導航欄 - 您需要手動填充導航欄（通過設置其 navigationItem ）。

（另請注意，如果您沒有"me44.png"圖像，則可能是您的代碼正在運行，但您只是沒有看到任何內容。）

Answer 2

盡管之前已經說明了，但您可能沒有看到添加到導航欄的按鈕。 對於Swift 3，請在AppDelegate類中嘗試這個（注意topItem ）：

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

    window = UIWindow()
    window?.backgroundColor = UIColor.white

    let navigationVC = UINavigationController(rootViewController: UIViewController())

    let addButton = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(addTodo))
    navigationVC.navigationBar.topItem?.rightBarButtonItem = addButton

    window?.rootViewController = navigationVC
    window?.makeKeyAndVisible()

    return true
}