SwiftUI一起学之九 -- 状态栏颜色修改

一 学习目标

在SwiftUI中动态修改状态栏颜色

二 学习效果

image.png image.png

三 主要操作步骤

3.1 自定义UIHostingController

class ContentHostingController: UIHostingController<ContentView> {
    private var currentStatusBarStyle: UIStatusBarStyle = .default
    override var preferredStatusBarStyle: UIStatusBarStyle {
        currentStatusBarStyle
    }
    func changeStatusBarStyle(_ style: UIStatusBarStyle) {
        self.currentStatusBarStyle = style
        self.setNeedsStatusBarAppearanceUpdate()
    }
}

3.2 SceneDelegate

if let windowScene = scene as? UIWindowScene {
    let window = UIWindow(windowScene: windowScene)
    // window.rootViewController = HostingController(rootView: contentView)
    window.rootViewController = ContentHostingController(rootView: contentView)
    self.window = window
    window.makeKeyAndVisible()
}

3.3 扩展UIApplication

extension UIApplication {
    class func setStatusBarStyle(_ style: UIStatusBarStyle) {
        if let vc = UIApplication.getKeyWindow()?.rootViewController as? ContentHostingController {
            vc.changeStatusBarStyle(style)
        }
    }
    private class func getKeyWindow() -> UIWindow? {
        return UIApplication.shared.windows.first{ $0.isKeyWindow }
    }
}

3.4 如何使用

UIApplication.setStatusBarStyle(.darkContent)
或
UIApplication.setStatusBarStyle(.lightContent)

四 完整代码

4.1 ContentHostingController.swift

import SwiftUI

class ContentHostingController: UIHostingController<ContentView> {
    private var currentStatusBarStyle: UIStatusBarStyle = .default
    override var preferredStatusBarStyle: UIStatusBarStyle {
        currentStatusBarStyle
    }
    func changeStatusBarStyle(_ style: UIStatusBarStyle) {
        self.currentStatusBarStyle = style
        self.setNeedsStatusBarAppearanceUpdate()
    }
    
}

extension UIApplication {
    class func setStatusBarStyle(_ style: UIStatusBarStyle) {
        if let vc = UIApplication.getKeyWindow()?.rootViewController as? ContentHostingController {
            vc.changeStatusBarStyle(style)
        }
    }
    private class func getKeyWindow() -> UIWindow? {
        return UIApplication.shared.windows.first{ $0.isKeyWindow }
    }
}

4.2 SceneDelegate.swift

import UIKit
import SwiftUI

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?


    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
        // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
        // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).

        // Create the SwiftUI view that provides the window contents.
        let contentView = ContentView()

        // Use a UIHostingController as window root view controller.
        if let windowScene = scene as? UIWindowScene {
            let window = UIWindow(windowScene: windowScene)
            window.rootViewController = ContentHostingController(rootView: contentView)
            self.window = window
            window.makeKeyAndVisible()
        }
    }

    func sceneDidDisconnect(_ scene: UIScene) {
        // Called as the scene is being released by the system.
        // This occurs shortly after the scene enters the background, or when its session is discarded.
        // Release any resources associated with this scene that can be re-created the next time the scene connects.
        // The scene may re-connect later, as its session was not necessarily discarded (see `application:didDiscardSceneSessions` instead).
    }

    func sceneDidBecomeActive(_ scene: UIScene) {
        // Called when the scene has moved from an inactive state to an active state.
        // Use this method to restart any tasks that were paused (or not yet started) when the scene was inactive.
    }

    func sceneWillResignActive(_ scene: UIScene) {
        // Called when the scene will move from an active state to an inactive state.
        // This may occur due to temporary interruptions (ex. an incoming phone call).
    }

    func sceneWillEnterForeground(_ scene: UIScene) {
        // Called as the scene transitions from the background to the foreground.
        // Use this method to undo the changes made on entering the background.
    }

    func sceneDidEnterBackground(_ scene: UIScene) {
        // Called as the scene transitions from the foreground to the background.
        // Use this method to save data, release shared resources, and store enough scene-specific state information
        // to restore the scene back to its current state.
    }


}

4.3 ContentView.swift

struct ContentView: View {
    @State var darkMode:Bool = false
    
    var body: some View {
        ZStack {
            Color.orange
            Button.init("点击变化状态栏文字颜色") {
                darkMode = !darkMode
                if(darkMode){
                    UIApplication.setStatusBarStyle(.darkContent)
                }else{
                    UIApplication.setStatusBarStyle(.lightContent)
                }
            }
        }.edgesIgnoringSafeArea(.all)
        .onAppear {
            UIApplication.setStatusBarStyle(.lightContent)
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}