Question

Apple WWDC视频＆＃34;使应用程序自适应，第2部分＆＃34; （参见https://developer.apple.com/videos/play/wwdc2016/233/）大约14:30分钟标记使用方法UINavigationBar。 forTraitCollection（）进行描述。从该视频中，可以看到使用该方法的一些代码：

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    let verticalCompactTrait = UITraitCollection(verticalSizeClass: .compact)
    let compactAppearance = UINavigationBar.forTraitCollection(verticalCompactTrait)
    compactAppearance.setBackgroundImage(nil, for: .default)

    let verticalRegularTrait = UITraitCollection(verticalSizeClass: .regular)
    let verticalAppearance = UINavigationBar.forTraitCollection(verticalRegularTrait)
    verticalAppearance.setBackgroundImage(UIImage(), for: .default)
}

我找不到有关forTraitCollection（）的文档。我一直在搜索Apple开发人员文档和Web。你能告诉我去哪儿吗？

Answer 1

视频中的代码已“进化”。目前正确的工作代码（iOS 10，swift 3）是：

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    // Override point for customization after application launch.

    let verticalCompactTrait = UITraitCollection(verticalSizeClass: .compact)
    let compactAppearance = UINavigationBar.appearance(for: verticalCompactTrait)
    compactAppearance.setBackgroundImage(nil, for: .default)

    let verticalRegularTrait = UITraitCollection(verticalSizeClass: .regular)
    let regularAppearance = UINavigationBar.appearance(for: verticalRegularTrait)
    let navBgImage:UIImage = UIImage(named: "someImage.jpg")!
    regularAppearance.setBackgroundImage(navBgImage, for: .default)
}

感谢rmaddy让我走上正轨。

找不到关于forTraitCollection的苹果文档

1 个答案: