iOS10中UserNotification解锁状态无Banners提示，锁屏正常问题求助

Hey there, sorry to hear you’ve been stuck with this frustrating notification problem for 3 days—let’s walk through the most likely fixes step by step.

1. Fix Foreground Notification Presentation (The #1 Cause) #

When your app is active in the foreground (unlocked, app open), iOS won’t show banner notifications unless you explicitly enable it in the willPresent delegate method. This is almost certainly why your notifications only work on the lock screen (where the app runs in the background).

Double-check your implementation of this method—make sure you’re passing .banner (iOS 15+) or .alert (older iOS versions) in the completion handler:

func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
    // Include .banner/.alert to show notifications while the app is active
    completionHandler([.banner, .sound])
}

If you haven’t implemented this method at all, or forgot to include the presentation option, foreground banners will never appear.

2. Verify Your Notification Scheduling Code #

Let’s confirm your 3-second trigger is set up correctly. A common mistake is accidentally using a longer interval, or ignoring errors that might block the notification from being scheduled.

Check your trigger and request code:

// Create your notification content first
let content = UNMutableNotificationContent()
content.title = "Test Notification"
content.body = "This should show up in 3 seconds"
content.sound = .default

// Set the 3-second trigger
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 3, repeats: false)

// Create and add the request
let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger)
UNUserNotificationCenter.current().add(request) { error in
    if let error = error {
        print("Failed to schedule notification: \(error.localizedDescription)")
    }
}

Make sure you’re checking the error closure—if there’s an error here, the notification might not be scheduled at all.

3. Check System-Level Notification Settings #

Sometimes the issue is outside your code. Head to Settings > Notifications > [Your App] and verify:

• Banner Style is set to either "Temporary" or "Persistent" (not "Off")
• Show as Banners is enabled
• In Notification Center and On Lock Screen are turned on (you already know the latter works, but confirming all settings helps rule out conflicts)

4. Test Background vs. Foreground Behavior #

To narrow down the issue:

• Leave your app in the background (unlock your phone, press home/swipe up to exit the app) and trigger the 3-second notification. Does it show up on time?
  • If yes: The problem is definitely in your foreground presentation logic (step 1).
  • If no: There might be system-level delays or scheduling issues. Try restarting your iPhone first—sometimes cached system processes can mess with notification timing.

5. Reset Notification Settings (Last Resort) #

If none of the above works, try resetting your device’s notification settings:

1. Go to Settings > General > Transfer or Reset iPhone > Reset
2. Select Reset All Settings (this won’t delete your apps or data, just reset system preferences like notifications, Wi-Fi passwords, etc.)
3. Re-test your notifications after the reset.

If you’re still stuck, share the full code for your notification setup (including all UNUserNotificationCenterDelegate methods) and we can dig deeper!

内容的提问来源于stack exchange，提问作者cheio