摘要:
介绍Xcode新建的SwiftUI模版项目结构、跟普通Storyboard模版项目的差异、SwiftUI项目的app启动流程、UIScene概念介绍、AppDelegate.swift和Info.plist的差异
1.项目模版
Interface: SwiftUI
Life Cycle: UIKit App Delegate
Language: Swift
Life Cycle选择UIKit App Delegate是为了项目模版有app生命周期，方便跟普通app生命周期做比较
2.差异性
1）AppDelegate.swift
import UIKit
@main
class AppDelegate: UIResponder, UIApplicationDelegate {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
return true
}
// MARK: UISceneSession Lifecycle
func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
// Called when a new scene session is being created.
// Use this method to select a configuration to create the new scene with.
return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
}
func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
// Called when the user discards a scene session.
// If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
// Use this method to release any resources that were specific to the discarded scenes, as they will not return.
}
}
app原本的生命周期不见了？增加了UISceneSession的生命周期！
swiftUI增加了Scene场景的概念，app可以切换scene场景
scene场景：pc电脑或某些iPad可以在一个app软件里面打开多个window窗口，一个window窗口就是对应一个scene场景，如火狐浏览器可以同时打开多个窗口，一个窗口显示百度首页，一个窗口显示火狐首页，如下：
