TextField类似于UIKit中的UITextField,用于实现用户的文字内容的输入。
示例代码:
struct ContentView : View { @State var username : String //用于接收用户在TextField中输入的内容,并在左侧添加@state关键词 //@State是指属性代理,它表示username属性将和界面上的元素进行绑定。当属性的值发生变化时,SwiftUI会立即通知绑定的视觉元素进行内容的更新 @State var nickname : String var body: some View { VStack{ Text("Your username is \(username)!") //由于username属性拥有@State标记,所以一旦username属性的值发生变化,文本视图上的文字内容也会立即刷新 Text("Your nickname is \(nickname)!") TextField("User Name", text: $username, onEditingChanged: { (value) in //设置text属性为username的值,$是指Binding wrapper绑定包装,表示可以修改属性的值 print("onEditingChanged:\(self.username)") //当用户修改文本输入框里的内容时,在控制台输出属性的值,实时观察属性的值的变化 }) { print("onCommit:\(self.username)") //当用户完成文本框里的输入时,在控制台输出username属性的值 }.textFieldStyle(RoundedBorderTextFieldStyle()) //设置TextField的样式为圆角边框样式 TextField("Nick Name", text: $nickname) .textFieldStyle(RoundedBorderTextFieldStyle()) } .padding() //只有实时预览模式才可以和界面中的元素进行交互 } //通过绑定包装特性,即可实现界面元素和数据内容的实时绑定 } #if DEBUG struct ContentView_Previews : PreviewProvider { static var previews: some View { ContentView(username: "", nickname: "") //由于给ContentView结构体添加了两个属性,所以需要更新PreviewProvider的属性的值,这样才可以在右侧的预览窗口显示正确的内容 } } #endif
SceneDelegate.swift:
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(username: "", nickname: "") //由于ContentView新增了两个属性,所以需要修改此处的初始化方法。 // Use a UIHostingController as window root view controller. if let windowScene = scene as? UIWindowScene { let window = UIWindow(windowScene: windowScene) window.rootViewController = UIHostingController(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 neccessarily 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. } }