iOS关闭App后点击推送通知无响应问题排查求助

App处于关闭状态时，点击推送通知后没有输出预期的app opened from PushNotification tap 2日志；但App在后台模式时，点击通知能正常输出app opened from PushNotification tap 1日志。请问遗漏了什么配置或代码？是否只有我遇到这个问题？

提供的代码 #

ContentView代码 #

import SwiftUI
import UserNotifications

struct ContentView: View {
    var body: some View {
        VStack {
            Button("Request Permission") {
                UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .badge, .sound]) { success, error in
                    if success {
                        print("Success")
                    } else if let error = error {
                        print(error.localizedDescription)
                    }
                }
            }

            Button("Schedule Notification") {
                let content = UNMutableNotificationContent()
                content.title = "Title"
                content.subtitle = "Subtitle"
                content.sound = UNNotificationSound.default

                let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 5, repeats: false)
                let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger)
                UNUserNotificationCenter.current().add(request)
            }
        }
    }
}

AppDelegate代码 #

class AppDelegate: NSObject, UIApplicationDelegate, UNUserNotificationCenterDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
        UNUserNotificationCenter.current().delegate = self
        return true
    }
    
    func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
        print("app opened from PushNotification tap 1")
        completionHandler()
    }
    
    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        print("app opened from PushNotification tap 2")
        completionHandler([.banner, .sound, .badge])
    }
}

原因及解决方案 #

你混淆了两个通知代理方法的触发场景：

• userNotificationCenter:willPresent:withCompletionHandler: 仅在App处于前台运行状态时被调用，作用是处理通知到达时的展示逻辑（比如是否显示横幅、播放声音），和点击通知打开App的操作无关，所以永远不会在App关闭/后台时点击通知触发。
• userNotificationCenter:didReceive:withCompletionHandler: 才是处理用户点击通知的回调，无论App是后台状态还是完全关闭状态，只要用户点击通知打开App，这个方法都会被调用。

另外需要确认一个关键配置：在SwiftUI的App入口中，必须通过UIApplicationDelegateAdaptor关联你的AppDelegate，否则代理方法不会生效。示例如下：

@main
struct YourAppName: App {
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
    
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

如果已经正确关联了AppDelegate，那问题就出在对两个代理方法的功能误解上，调整日志输出的位置即可：把"app opened from PushNotification tap 2"的逻辑移到didReceive response方法中，或者修正日志描述以匹配方法的实际作用。

内容的提问来源于stack exchange，提问作者Sergei Kirasirov