[英]iOS 8 Swift navigation bar title, buttons not showing in tab based application
我试图按照本教程 , 本答案和本答案来为iOS 8 / Swift中基于选项卡的应用程序中的每个选项卡创建导航栏,但是导航栏上没有显示标题或按钮。
这是我到目前为止的内容:
// AppDelegate.swift
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
let tabBarController = UITabBarController()
let vc1 = ViewController()
let vc2 = ViewController()
let vc3 = ViewController()
let nc1 = UINavigationController(rootViewController: vc1)
let nc2 = UINavigationController(rootViewController: vc2)
let nc3 = UINavigationController(rootViewController: vc3)
let controllers = [nc1,nc2,nc3]
tabBarController.viewControllers = controllers
nc1.tabBarItem = UITabBarItem(title: "item1", image: nil, tag: 1)
nc2.tabBarItem = UITabBarItem(title: "item2", image: nil, tag: 1)
nc3.tabBarItem = UITabBarItem(title: "item3", image: nil, tag: 1)
window = UIWindow(frame: UIScreen.mainScreen().bounds)
window?.rootViewController = tabBarController
window?.makeKeyAndVisible()
return true
}
// ViewController.swift
class ViewController: UIViewController, UINavigationBarDelegate {
override func viewDidLoad() {
super.viewDidLoad()
let navigationBar = UINavigationBar(frame: CGRectMake(0, 0, self.view.frame.size.width, 44))
navigationBar.backgroundColor = UIColor.blueColor()
navigationBar.delegate = self;
let navigationItem = UINavigationItem()
navigationItem.title = "Title"
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
navigationBar.items = [navigationItem]
}
func positionForBar(bar: UIBarPositioning) -> UIBarPosition {
return UIBarPosition.TopAttached
}
}
但是我只是在模拟器顶部获得了一个空白的导航栏。
你让一个自定义UINavigationBar
,当一个已经与提供给您UINavigationController
。
在您的ViewController
尝试以下方法:
override func viewDidLoad() {
super.viewDidLoad()
self.title = "Title"
let navigationBar = navigationController!.navigationBar
navigationBar.tintColor = UIColor.blueColor()
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
}
无需使用新的导航栏,只需使用现有的导航栏即可。 记住你在这里做什么:
let nc1 = UINavigationController(rootViewController: vc1)
因此,您的视图控制器已经嵌入了导航控制器中,只需使用self
即可访问导航项
self.title = "Your Title"
var homeButton = UIBarButtonItem(title: "LeftButton", style: .Plain, target: self, action: "")
var logButton = UIBarButtonItem(title: "RigthButton", style: .Plain, target: self, action: "")
self.navigationItem.leftBarButtonItem = homeButton
self.navigationItem.rightBarButtonItem = logButton
我不必要创建两个导航栏。 导航控制器带有导航栏,我将ViewController更改为:
class ViewController: UIViewController, UINavigationBarDelegate {
override func viewDidLoad() {
super.viewDidLoad()
self.navigationItem.title = "My Title"
self.navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Left Button", style: UIBarButtonItemStyle.Plain, target: self, action: nil)
self.navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Right Button", style: UIBarButtonItemStyle.Plain, target: self, action: nil)
}
func positionForBar(bar: UIBarPositioning) -> UIBarPosition {
return UIBarPosition.TopAttached
}
}
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