未来通知的时间戳不正确

Question

当我的应用程序启动时，它会执行 API 调用，然后根据结果安排通知。这相当于安排了大约 10 个通知。实际通知上显示的时间戳似乎存在问题。

由于我正在创建这些通知，然后使用 AlarmManager 安排警报，因此通知上的默认时间将是创建通知的时间 (System.currentTimeMillis())。

我尝试在Notification.Builder 上使用.setWhen() 方法将其设置为我用来安排前面提到的警报的时间。不过这样会好一些，因为不能保证通知会在指定的确切时间送达，我经常会在过去几分钟收到通知。

此外，我尝试在BroadcastReceiver 中的通知上手动覆盖when 字段，就在实际调用.notify() 之前：

public class NotificationPublisher extends BroadcastReceiver {

    public static String NOTIFICATION_ID = "notification_id";
    public static String NOTIFICATION = "notification";

    public void onReceive(Context context, Intent intent) {

        NotificationManager notificationManager = (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);

        Notification notification = intent.getParcelableExtra(NOTIFICATION);
        notification.when = System.currentTimeMillis();
        int id = intent.getIntExtra(NOTIFICATION_ID, 0);
        notificationManager.notify(id, notification);

    }
}

但是，在上述场景中，.when 似乎被忽略了。

坦率地说，我只是在寻找一种方法，让通知上显示的时间戳成为实际显示的时间。

Answer 1

我建议将您的通知信息作为附加信息传递，然后在 BroadcastReceiver 中构建通知。这将在发出通知之前构建通知，因此它与您的 AlarmManager 触发 BroadcastReceiver 的时间相同。

从您安排通知的任何位置：

private void scheduleNotification(){

    // Create an intent to the broadcast receiver you will send the notification from
    Intent notificationIntent = new Intent(this, SendNotification.class);

    // Pass your extra information in
    notificationIntent.putExtra("notification_extra", "any extra information to pass in");

    int requestCode = 1;

    // Create a pending intent to handle the broadcast intent
    PendingIntent alarmIntent = PendingIntent
                .getBroadcast(this, requestCode, notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);

    // Set your notification's trigger time
    Calendar alarmStart = Calendar.getInstance();
    alarmStart.setTimeInMillis(System.currentTimeMillis());
    alarmStart.set(Calendar.HOUR_OF_DAY, 6); // This example is set to approximately 6am

    AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);

    // Set the alarm with the pending intent
    // be sure to use set, setExact, setRepeating, & setInexactRepeating 
    // as well as RTC_WAKEUP, ELAPSED_REALTIME_WAKEUP, etc. 
    // where appropriate
    alarmManager.set(AlarmManager.RTC_WAKEUP, alarmStart.getTimeInMillis(), alarmIntent);
}

然后，在 BroadcastReceiver 的 onReceive 中：

String notificationExtra = null;

// Retrieve your extra data
if(intent.hasExtra("notification_extra")){
    notificationExtra = intent.getStringExtra("notification_extra");
}

//Build the notification
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context);
mBuilder.setSmallIcon(notificationIcon)
        .setContentTitle(notificationTitle)
        .setContentText(notificationMessage)
        .setAutoCancel(true); // Use AutoCancel true to dismiss the notification when selected

// Check if notificationExtra has a value
if(notificationExtra != null){
    // Use the value to build onto the notification
}

//Define the notification's action
Intent resultIntent = new Intent(context, MainActivity.class); // This example opens MainActivity when clicked

int requestCode = 0;

PendingIntent resultPendingIntent =
        PendingIntent.getActivity(
                context,
                requestCode,
                resultIntent,
                PendingIntent.FLAG_UPDATE_CURRENT
        );

//Set notification's click behavior
mBuilder.setContentIntent(resultPendingIntent);

// Sets an ID for the notification
int mNotificationId = 1;

// Gets an instance of the NotificationManager service
NotificationManager mNotifyMgr =
        (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

// Builds the notification and issues it.
mNotifyMgr.notify(mNotificationId, mBuilder.build());

Answer 2

您的 NotificationPublisher 的 onReceive() 方法将是 invoked 仅当预定 alarm 触发指定 time。当您从onReceive() 方法创建通知时，它肯定会显示当前时间。无需使用.when 或.setWhen() 方法。

试试这个：

public class NotificationPublisher extends BroadcastReceiver {

    public static String NOTIFICATION_ID = "notification_id";
    public static String NOTIFICATION = "notification";

    public void onReceive(Context context, Intent intent) {

        int id = intent.getIntExtra(NOTIFICATION_ID, 0);

        // Notification
        Notification notification = new Notification.Builder(context)       
            .setContentTitle("This is notification title")
            .setContentText("This is notification text")
            .setSmallIcon(R.mipmap.ic_launcher).build();

        notification.flags |= Notification.FLAG_AUTO_CANCEL;

        // Notification Manager
        NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

        notificationManager .notify(id, notification);
    }
}

如果您想在单击Notification 时重定向到activity，则可以使用PendingIntent 并将其设置为您的Notification。

public class NotificationPublisher extends BroadcastReceiver {

    public static String NOTIFICATION_ID = "notification_id";
    public static String NOTIFICATION = "notification";

    public void onReceive(Context context, Intent intent) {

        int id = intent.getIntExtra(NOTIFICATION_ID, 0);

        Intent intent = new Intent(context, YourTargetActivity.class);
        intent.putExtra("KEY_ID", id); // Pass extra values if needed

        PendingIntent pI = PendingIntent.getActivity(context, id, intent, PendingIntent.FLAG_UPDATE_CURRENT);

        // Notification
        Notification notification = new Notification.Builder(context)       
            .setContentTitle("This is notification title")
            .setContentText("This is notification text")
            .setSmallIcon(R.mipmap.ic_launcher)
            .setContentIntent(pI).build();

        notification.flags |= Notification.FLAG_AUTO_CANCEL;

        // Notification Manager
        NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

        notificationManager .notify(id, notification);
    }
}

希望对你有帮助~

Answer 3

我也为此苦苦挣扎了一段时间，但是您的问题实际上使我得到了最佳答案。我检查了 setWhen() ，现在看起来效果很好（使用 API lvl 30 和 31 检查）。由于这篇文章已经有几年了，也许这个问题在此期间已经解决了。下面是我在 Kotlin 中的做法：

class NotificationPublisher : BroadcastReceiver() {
override fun onReceive(context: Context, intent: Intent) {
    val notificationManager = context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
    val notification = intent.getParcelableExtra<Notification>(NOTIFICATION)
    notification?.`when` = System.currentTimeMillis()                               // overwriting the creation time to show the current trigger time when the notification is shown
    val postId = intent.getIntExtra(NOTIFICATION_ID, 0)

    notificationManager.notify(postId, notification)
}