选项卡栏中的导航栏中的按钮UIViewController未显示

Question

I can't seem to get any buttons to appear in my navigation bar.

Flow: Navigation Controller -> Tab bar Controller -> ViewController (want to put button here)

I've tried adding it programmatically inside of ViewDidLoad:

let navigationBar = navigationController!.navigationBar
    navigationBar.tintColor = UIColor.blackColor()

let leftButton =  UIBarButtonItem(title: "Left Button", style: UIBarButtonItemStyle.Plain, target: self, action: nil)
let rightButton = UIBarButtonItem(title: "Right Button", style: UIBarButtonItemStyle.Plain, target: self, action: nil)

    navigationItem.leftBarButtonItem = leftButton
    navigationItem.rightBarButtonItem = rightButton

I've also tried adding it using the storyboard but it doesnt show during runtime. Any idea why I can't get a button to appear in the navigation bar

Answer 1

试试这样：

self.tabBarController?.navigationItem.leftBarButtonItems = [leftButton]

Answer 2

views from storyboard or xib load after viewWillAppear method call. and viewDidLoad method call before viewWillAppear.

so navigation bar is nil during viewDidLoad method so they are not appear.so write you code in viewdidappear method and your buttons will be appeared.