如何设置每日重复通知？通知仅触发一次问题求助

Hey there! Let's figure out why your notification only fires once—this is a super common gotcha with iOS UserNotifications. From the code snippet you shared, it looks like you're missing a few critical pieces to make the notification repeat reliably. Let's break this down and fix it step by step.

Common Culprits for One-Time Notifications #

Before jumping into code, let's cover the most likely reasons your repeat logic isn't working:

• You didn't set repeats: true on your notification trigger (the #1 mistake here)
• You're reusing the same notification identifier without removing old requests, causing new ones to overwrite the old (and broken) ones
• Your date components are too specific (like including a fixed day/year) instead of targeting just hour/minute for daily repeats

Corrected Full Code #

Here's the updated version of your function with all the necessary fixes:

static func scheduleNotification(hour: Int, minutes: Int, completion: @escaping (Bool) -> ()) {
    // 1. Build out your notification content
    let notificationContent = UNMutableNotificationContent()
    notificationContent.title = "Hello!"
    notificationContent.body = "Time for your daily check-in!" // Add a body so users know what it's for
    notificationContent.sound = UNNotificationSound.default // Ensure users get an audio cue (optional but helpful)
    
    // 2. Set up date components to target the specific hour/minute every day
    var dateComponents = DateComponents()
    dateComponents.hour = hour
    dateComponents.minute = minutes
    // Leave out day/month/year so it repeats daily
    
    // 3. Create the trigger with REPEATS ENABLED (this is the key!)
    let trigger = UNCalendarNotificationTrigger(
        dateMatching: dateComponents,
        repeats: true
    )
    
    // 4. Use a unique identifier (or fixed ID if you want to update this same notification later)
    let notificationId = "DailyReminder_\(hour)_\(minutes)"
    
    // 5. First remove any existing pending notifications with the same ID
    // This prevents overwriting issues if you re-schedule with a new time
    UNUserNotificationCenter.current().removePendingNotificationRequests(
        withIdentifiers: [notificationId]
    )
    
    // 6. Build the notification request
    let request = UNNotificationRequest(
        identifier: notificationId,
        content: notificationContent,
        trigger: trigger
    )
    
    // 7. Add the request to the notification center
    UNUserNotificationCenter.current().add(request) { error in
        if let error = error {
            print("Notification scheduling failed: \(error.localizedDescription)")
            completion(false)
        } else {
            print("Daily notification scheduled successfully!")
            completion(true)
        }
    }
}

Key Fixes Explained #

Let's call out the most important changes:

• repeats: true on the trigger: This tells iOS to fire the notification every time the date components match (in this case, every day at your specified hour/minute). Without this, it only fires once.
• Removing old pending requests: If you ever re-run this function to update the notification time, removing the old request first ensures the new trigger takes effect immediately.
• Simplified date components: By only setting hour and minute, we ensure the trigger matches that time every day. If you added a specific day or year, it would only fire once on that exact date.

Additional Checks to Ensure It Works #

Don't forget these critical steps outside the function:

1. Request notification permissions: You need to ask the user for permission to send notifications before anything will show up. Add this to your app's launch code (like AppDelegate or SceneDelegate):

   UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) { granted, error in
       if granted {
           print("Notification permission approved!")
       } else {
           print("Notification permission denied—user won't see alerts.")
       }
   }
   

2. Verify device settings: Double-check that your app has notifications enabled in the device's Settings > [Your App] > Notifications.
3. Test with a near-future time: If you set the time to a past hour (e.g., 9 AM when it's currently 10 AM), iOS will wait until the next day at 9 AM to fire it. Test with a time 5 minutes from now to see it work immediately.

内容的提问来源于stack exchange，提问作者codechef