setRightBarButtonItems不起作用

Question

I am trying to have 2 buttons on the right of a UINavigationBar . Below is the source code. No error but there is no button either. It is a UIViewController , not a 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

This code is just wrong:

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

You do not set the navigation controller's navigationItem ; you set your navigationItem . Also, the [AnyObject] thing is just unnecessary. So:

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

However, note that that works only if your view controller is the child of a UINavigationController. Setting a view controller's navigationItem populates a navigation bar automatically only in that situation. If you are not in that situation — ie, if you just have a "loose" navigation bar in your interface — you need to populate your navigation bar manually (by setting its navigationItem ).

(Also, note that if you have no "me44.png" image, it could be that your code is working but you just aren't seeing anything.)

Answer 2

Despite all indicated previously, it's possible that you don't see the added button to navigation bar. For Swift 3, try this in the AppDelegate class (pay attention to 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
}