Question

我在Superview中以编程方式添加了名为BaseViewController的UINavigationBar，它继承了UIViewController。但是当我尝试为UINavigationBar设置标题时。我收到名为致命错误的错误：无法解包Optional.None

以下是我的快速课程。如何解包和更改UINavigationBar标题

import UIKit

class BaseViewConroller: UIViewController {
    var navBar:UINavigationBar=UINavigationBar()

    override func viewDidLoad() {
        super.viewDidLoad()
        setNavBarToTheView()
        // Do any additional setup after loading the view.
        navBar.topItem.title="test test"
    }

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

    func setNavBarToTheView()
    {
        navBar.frame=CGRectMake(0, 0, 320, 50)
        navBar.backgroundColor=(UIColor .blackColor())
        self.view .addSubview(navBar)
    }

}

Answer 1

将navBar.topItem.title="test test"替换为self.title="test test"。干杯！！

Answer 2

UILabel *labelTitle = UILabel(frame: CGRectZero);
labelTitle.text = "Title";
labelTitle.text.textAlignment = NSTextAlignment.Center
self.navigationItem.titleView = labelTitle;

我有这段代码......我希望，这可以帮助你。

Answer 3

以实际方式更改导航栏文本。只需调用下面写的func setNavigationBarTitleText("WhateverTextNeeded")即可。我假设您已经配置了UINavigationBar。

var navBar = UINavigationBar(frame: CGRectZero)

func setNavigationBarTitleText(text: String){
    let titleLabel = UILabel(frame: CGRectMake(0, 0, view.frame.size.width - 120, 44))
    titleLabel.backgroundColor = UIColor.clearColor()
    titleLabel.numberOfLines = 2
    titleLabel.font = UIFont(name: UIConfig.Fonts.OswaldRegular,  size: 16)
    titleLabel.textAlignment = NSTextAlignment.Center
    titleLabel.text = text.uppercaseString
    self.navBar.topItem?.titleView = titleLabel
}

我希望这会有所帮助。

Answer 4

您可以使用此代码转换导航栏。

 self.navigationController?.navigationBar.backIndicatorImage = UIImage(named: "imageName")
    self.navigationController?.navigationBar.backIndicatorTransitionMaskImage = UIImage(named: "imageName")
    self.navigationController?.navigationBar.backItem?.title = ""
    self.navigationController?.navigationBar.tintColor = UIColor.white
    self.title = "Title"

在iOS8 Swift中更改UINavigationBar标题

4 个答案: