init(DelegateType .Type)
DelegateType
inherits NSObject
, DelegateType
conforms to NSApplicationDelegate
, and DelegateType
conforms to ObservableObject
.init(DelegateType .Type)
Availability 有効性
Technology
@propertyWrapper struct NSApplicationDelegateAdaptor<DelegateType> where DelegateType : NSObject
, DelegateType : NSApplicationDelegate
To handle app delegate callbacks in an app that uses the SwiftUI life cycle, define a type that conforms to the NSApplication
protocol, and implement the delegate methods that you need. For example, you can implement the application(_:
method to handle remote notification registration:
class MyAppDelegate: NSObject, NSApplicationDelegate, ObservableObject {
func application(
_ application: NSApplication,
didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data
) {
// Record the device token.
}
}
Then use the NSApplication
property wrapper inside your App
declaration to tell SwiftUI about the delegate type:
@main
struct MyApp: App {
private var appDelegate: MyAppDelegate
var body: some Scene { ... }
}
SwiftUI instantiates the delegate and calls the delegate’s methods in response to life cycle events. Define the delegate adaptor only in your App
declaration, and only once for a given app. If you declare it more than once, SwiftUI generates a runtime error.
If your app delegate conforms to the Observable
protocol, as in the example above, then SwiftUI puts the delegate it creates into the Environment
. You can access the delegate from any scene or view in your app using the Environment
property wrapper:
private var appDelegate: MyAppDelegate
This enables you to use the dollar sign ($
) prefix to get a binding to published properties that you declare in the delegate. For more information, see projected
.
Important 重要
Manage an app’s life cycle events without using an app delegate whenever possible. For example, prefer to handle changes in Scene
instead of relying on delegate callbacks, like application
.
init(DelegateType .Type)
DelegateType
inherits NSObject
, DelegateType
conforms to NSApplicationDelegate
, and DelegateType
conforms to ObservableObject
.init(DelegateType .Type)
var projectedValue : ObservedObject <DelegateType >.Wrapper
DelegateType
inherits NSObject
, DelegateType
conforms to NSApplicationDelegate
, and DelegateType
conforms to ObservableObject
.var wrappedValue : DelegateType
struct UIApplicationDelegateAdaptor
struct WKExtensionDelegateAdaptor