如何在手机锁定时显示弹出通知？

Question

I want to show this notification as pop-up window or alert dialogue on the lock screen.

public void onMessageReceived(RemoteMessage remoteMessage) {
    super.onMessageReceived(remoteMessage);

    String title = remoteMessage.getNotification().getTitle();
    String body = remoteMessage.getNotification().getBody();

    Map<String, String> extraData = remoteMessage.getData();

    String brandID = extraData.get("brandID");
    String category = extraData.get("category");

    Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
    NotificationCompat.Builder builder = new NotificationCompat.Builder(this, "TAC")
            .setContentText(body)
            .setContentTitle(title)
            .setSound(defaultSoundUri)
            .setDefaults(Notification.DEFAULT_ALL) // must requires VIBRATE permission
            .setPriority(NotificationCompat.PRIORITY_HIGH) //must give priority to High, Max which will considered as heads-up notification
            .setDefaults(Notification.DEFAULT_ALL)
            .setSmallIcon(R.drawable.ic_launcher_background);

    Intent intent;
    if(category.equals("shoes")){
        intent = new Intent(this, ReceiveNotification.class);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP);
    }
    else {
        intent = new Intent(this, ReceiveNotification.class);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    }
    intent.putExtra("brandID", brandID);
    intent.putExtra("category", category);

    PendingIntent pendingIntent
            = PendingIntent.getActivity(this, 10, intent, PendingIntent.FLAG_UPDATE_CURRENT);
    builder.setContentIntent(pendingIntent);
    NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
        NotificationChannel notificationChannel = new NotificationChannel("TAC", "demo", NotificationManager.IMPORTANCE_HIGH);
        manager.createNotificationChannel(notificationChannel);
    }
    int id = (int) System.currentTimeMillis();
    manager.notify(id, builder.build());

}

Answer 1

To control the level of detail visible in the notification from the lock screen, call setVisibility() and specify one of the following values:

• VISIBILITY_PUBLIC shows the notification's full content.
• VISIBILITY_SECRET doesn't show any part of this notification on the lock screen.
• VISIBILITY_PRIVATE shows basic information, such as the notification's icon and the content title, but hides the notification's full content.

When VISIBILITY_PRIVATE is set, you can also provide an alternate version of the notification content which hides certain details. For example, an SMS app might display a notification that shows You have 3 new text messages but hides the message contents and senders. To provide this alternative notification, first create the alternative notification with NotificationCompat.Builder as usual. Then attach the alternative notification to the normal notification with setPublicVersion() .

However, the user always has final control over whether their notifications are visible on the lock screen and can even control that based on your app's notification channels.

For more detail click here