获取Bundle信息

获取Bundle中的信息，一个做法是读取info.plist文件，将读到的数据转成json来获取

var config: [String: Any]?
if let infoPlistPath = Bundle.main.url(forResource: "Info", withExtension: "plist") {
    do {
        let infoPlistData = try Data(contentsOf: infoPlistPath)
        if let dict = try PropertyListSerialization.propertyList(from: infoPlistData, options: [], format: nil) as? [String: Any] {
            config = dict
        }
    } catch {
        print(error)
    }
}

使用PropertyListSerialization.propertyList将infoPlistData转成dict，整个获取的过程比较原始，其实Apple有提供一些API直接获取

print(Bundle.main.object(forInfoDictionaryKey: "CFBundleName")!)
print(Bundle.main.object(forInfoDictionaryKey: "CFBundleVersion")!)
print(Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString")!)

object是Bundle实例上的办法，forInfoDictionaryKey指定的key对应的value，整个使用体会比上一份读取info文件要好太多了。能够给Bundle增加extension，更方便调用

extension Bundle {
    var appName: String? {
        return object(forInfoDictionaryKey: "CFBundleName") as? String
    }
    var appVersion: String? {
        return object(forInfoDictionaryKey: "CFBundleVersion") as? String
    }
    var buildNumber: String? {
        return object(forInfoDictionaryKey: "CFBundleShortVersionString") as? String
    }
}

乐滋滋啊……

而且object的API还比直接读取plist文件多一个功能，便是在有国际化的时分，object能直接获取到本地文件资源，能够自己试一下。

获取RootViewController

在iOS13之前，能够这样直接获取keyWindow和 root viewController
UIApplication.shared.keyWindow?.rootViewController

但是iOS13支撑了多视窗（multiple scenes），iOS15中UIApplication.shared.keyWindow?就要不支撑了，所以iOS13之后，获取keyWindow的写法有些调整

extension UIApplication {
    var firstKeyWindow: UIWindow? {
        let windowScenes = UIApplication.shared.connectedScenes.compactMap{$0 as? UIWindowScene}
        let activeScene = windowScenes.filter { $0.activationState == .foregroundActive }
        let firstActiveScene = activeScene.first
        let keyWindow = firstActiveScene?.keyWindow
        return keyWindow
    }
}
  • UIApplication.shared.connectedScenes获取到一切视窗，并经过compactMap转成UIWindowScene对象
  • Multiple Windows意味着会获取到不止一个active scene，默许获取到一切activeScene的第一个
  • 从active scene对象上获取keyWindow对象回来

之后能够用这个extension的firstKeyWindow获取rootViewController（有点像iOS13之前的用法了）
let vc = UIApplication.shared.firstKeyWindow?.rootViewController

UIWindowScene.keyWindow到iOS15才支撑，iOS13中需要咱们自己手动过滤下keyWindow的挑选，代码改动如下（更紧凑些）：

var firstKeyWindow: UIWindow? {
    return UIApplication.shared.connectedScenes
        .compactMap { $0 as? UIWindowScene }
        .filter { $0.activationState == .foregroundActive }
        .first?.windows
        .first(where: .isKeyWindow)
}

使用了 window.first(where: .isKeyWindow)来获取keywindow，它是UIWindow的一个属性