导航栏内容未显示

Question

我正在努力让所有导航栏元素显示在我正在创建的应用中。你可以看到右边的按钮显示正常，但我的标题和我的后退按钮没有显示。如果我将backButtonItem下面的代码更改为leftBarButton，则可以正常使用。

当我说我尝试过几个SO帖子时，请相信我，即使我正在创建这个帖子，我也在查找相关帖子，但我找不到任何有效的帖子。

这是我的UINavigationController课程：

import UIKit
class NavViewController: UINavigationController, UINavigationBarDelegate {
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(true)

        let navigationBar = UINavigationBar(frame: CGRectMake(0, 20, self.view.frame.size.width, 44)) // Offset by 20 pixels vertically to take the status bar into account
        navigationBar.barTintColor = UIColor(red: 0.0627, green: 0.4862, blue: 0.0627, alpha: 1)
        navigationBar.delegate = self;
        // Create a navigation item with a title
        let navigationItem = UINavigationItem()

        //Create the Back Button
        let backButton = UIBarButtonItem(title: "Back", style: UIBarButtonItemStyle.Plain, target: self, action: nil)
        backButton.tintColor = UIColor(red: 255, green: 255, blue: 255, alpha: 1)
        navigationItem.backBarButtonItem = backButton

        //Create the Right Button (Go Home) Button
        let rightButton = UIBarButtonItem(title: "Home", style: UIBarButtonItemStyle.Plain, target: self, action: "goHome")
        rightButton.tintColor = UIColor(red: 255, green: 255, blue: 255, alpha: 1)
        navigationItem.rightBarButtonItem = rightButton

        //Change the Navigation Bar Title Color
        navigationBar.titleTextAttributes = [NSForegroundColorAttributeName:UIColor.whiteColor()]

        // Assign the navigation item to the navigation bar
        navigationBar.items = [navigationItem]

        // Make the navigation bar a subview of the current view controller
        self.view.addSubview(navigationBar)
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

您可以给予我任何帮助将不胜感激。 感谢!!!!

修改

所以我继续把它添加到我的appdelegate.swift中，我可以让后退按钮显示我想要的方式以及我的标题，但不是我的右按钮不显示。

import UIKit

@UIApplicationMain class AppDelegate : UIResponder, UIApplicationDelegate {

var window : UIWindow?
var navigationItem = UINavigationItem()

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    window!.backgroundColor = UIColor(red: 0.2078, green: 0.2078, blue: 0.2078, alpha: 1)


    //Create the Back Button
    let backButton = UIBarButtonItem(title: "", style: UIBarButtonItemStyle.Plain, target: self, action: nil)
    navigationItem.backBarButtonItem = backButton

    //Create the Right Button (Go Home) Button
    let rightButton = UIBarButtonItem(title: "Home", style: UIBarButtonItemStyle.Plain, target: self, action: "goHome")
    navigationItem.rightBarButtonItem = rightButton


    // Assign the navigation item to the navigation bar
    UINavigationBar.appearance()?.items = [navigationItem]

    //Change the Navigation Bar Color
    UINavigationBar.appearance()?.titleTextAttributes = [NSForegroundColorAttributeName:UIColor.whiteColor()]

    UINavigationBar.appearance()?.tintColor = UIColor.whiteColor()
    UINavigationBar.appearance()?.barTintColor = UIColor(red: 0.0627, green: 0.4862, blue: 0.0627, alpha: 1)

    return true
}

    func goHome() {
        var rootViewController = self.window!.rootViewController as UINavigationController
        let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        var homeViewController = mainStoryboard.instantiateViewControllerWithIdentifier("Home") as HomeViewController
        rootViewController.popToViewController(homeViewController, animated: true)
    }

}

Answer 1

根据您的问题，似乎您不希望在单个调用中设置左右按钮，并且您需要通过编写一次来获取它们并将它们放入所有其他类中。这是你需要做的。

在AppDelegate.swift中

func application（application：UIApplication，didFinishLaunchingWithOptions launchOptions：[NSObject：AnyObject]？） - ＆gt;布尔{

    UINavigationBar.appearance().titleTextAttributes = [NSForegroundColorAttributeName:UIColor.whiteColor()]
    UINavigationBar.appearance().barTintColor = UIColor(red: 0.0627, green: 0.4862, blue: 0.0627, alpha: 1)
    UINavigationBar.appearance().tintColor = UIColor.whiteColor()
    return true
}

以上代码将在整个应用程序中为导航栏设置此属性。

现在，添加新文件并将其命名为RootViewController - “UIViewController的子类”。

导入UIKit

类RootViewController：UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func setLeftBarButton() {
    // Below line will Create Custom leftBarButton.
    var backBtn = UIBarButtonItem(title: "First", style: UIBarButtonItemStyle.Bordered, target: self, action: "popBack") as UIBarButtonItem
    self.navigationItem.leftBarButtonItem = backBtn
    // Below line will Remove default backBarButton.
    self.navigationItem.backBarButtonItem = nil;
}

func setRightBarButton() {
    let rightBtn: UIBarButtonItem = UIBarButtonItem(title: "Home", style: UIBarButtonItemStyle.Bordered, target: self, action: "goToNext")
    self.navigationItem.rightBarButtonItem = rightBtn
}

func popBack() {
    self.navigationController?.popViewControllerAnimated(true)
}

func goToNext() {
    print("Go to Next View.")
}

现在在你所有的View Controller中你只需要“替换 - 用RootViewController替换UIViewController”。

现在在Second View Controller中你需要做的就是从SecondViewController的ViewDidLoad中的RootViewController调用方法。
覆盖func viewDidLoad（）{
        super.viewDidLoad（）
        self.navigationItem.title =“第二视图”
        setLeftBarButton（）
        setRightBarButton（）
        //加载视图后进行任何其他设置     }

输出：

希望这可以解决您的问题。

Answer 2

@KyleMassacre，UINavigationController用于从一个控制器导航到另一个控制器UINavigationController Apple Doc

自动显示后退按钮。

在您的AppDelegation中，您只需要：

        //Change the Navigation Bar Color
    UINavigationBar.appearance()?.titleTextAttributes = [NSForegroundColorAttributeName:UIColor.whiteColor()]

    UINavigationBar.appearance()?.tintColor = UIColor.whiteColor()
    UINavigationBar.appearance()?.barTintColor = UIColor(red: 0.0627, green: 0.4862, blue: 0.0627, alpha: 1)

在具有2个视图控制器的示例中。按钮“推”从第一个View Controller到SecondViewController：

SecondViewController中的代码：

import UIKit

类Sec​​ondViewController：UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
    let rightButton = UIBarButtonItem(title: "Home", style: UIBarButtonItemStyle.Plain, target: self, action: "goHome")
    rightButton.tintColor = UIColor(red: 255, green: 255, blue: 255, alpha: 1)
    navigationItem.rightBarButtonItem = rightButton


}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


/*
// MARK: - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    // Get the new view controller using segue.destinationViewController.
    // Pass the selected object to the new view controller.
}
*/

func goHome() {

    // navigation where you want. You can use:
    //navigationController?.pushViewController(<#viewController: UIViewController#>, animated: <#Bool#>)
    //navigationController?.popToRootViewControllerAnimated(animated: Bool)
    //presentViewController(<#viewControllerToPresent: UIViewController#>, animated: <#Bool#>, completion: <#(() -> Void)?##() -> Void#>)
}

}

结果：