How to send notification without being online?

Question

I am building an app that a user will put their tests and assignments and whatever in. I want to know will it be possible for my app to bring up a notification like a week and a day before the test?

Everywhere I look its just about firebase notifications and push notifications.

I don't want these online notification, I'll need the app to send them by itself offline. Is this possible?

Yes you can trigger local push notification by sceduling time with alarm manager.. — Mohamed Mohaideen AH, Sep 05 '18 at 07:10
@MohamedMohaideenAH Thank you, I appreciate the response. Any place you know of that has a good tutorial or somewhere with good insight on how to do it? — Erbez, Sep 05 '18 at 07:12
@RavindraKushwaha Thank you as well, only saw your comment when I scrolled up, please see my above comment. — Erbez, Sep 05 '18 at 07:13
see http://droidmentor.com/schedule-notifications-using-alarmmanager/ for reference — Manohar, Sep 05 '18 at 07:14
@Erbez Please have a look on this solution https://stackoverflow.com/questions/36550991/repeating-alarm-for-specific-days-of-week-android — Ravindra Kushwaha, Sep 05 '18 at 07:15

Mohamed Mohaideen AH · Accepted Answer · 2018-10-04T07:08:52.497

Let me add some workaround you can find more tutorial outside..

First create receiver class extends BroadcastReceiver.

public class ReminderReceiver extends BroadcastReceiver {


@Override
public void onReceive(Context context, Intent intent) {
    int Request_Code = intent.getExtras().getInt("TIME",0);
    showNotification(context, MainActivity.class,
            "New Notification Alert..!", "scheduled for " + Request_Code + " seconds",Request_Code);
}

public void showNotification(Context context, Class<?> cls, String title, String content,int RequestCode)
{
    Uri alarmSound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);

    Intent notificationIntent = new Intent(context, cls);
    notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

    TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);
    stackBuilder.addParentStack(cls);
    stackBuilder.addNextIntent(notificationIntent);

    PendingIntent pendingIntent = stackBuilder.getPendingIntent(
            RequestCode,PendingIntent.FLAG_ONE_SHOT);

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

   if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        CharSequence name = context.getString(R.string.channel_name);
        String description = context.getString(R.string.channel_description);
        int importance = NotificationManager.IMPORTANCE_DEFAULT;
        NotificationChannel channel = new NotificationChannel("my_channel_01", name, importance);
        channel.setDescription(description);
        // Register the channel with the system; you can't change the importance
        // or other notification behaviors after this
        notificationManager.createNotificationChannel(channel);
    }

    NotificationCompat.Builder builder = new NotificationCompat.Builder(context,"my_channel_01");
    Notification notification = builder.setContentTitle(title)
            .setContentText(content).setAutoCancel(true)
       .setSound(alarmSound).setSmallIcon(R.drawable.ic_launcher_background)
            .setContentIntent(pendingIntent).build();


    notificationManager.notify(RequestCode,notification);
}

}

Declare receiver in manifest class below activity tag..

 <receiver android:enabled="true" android:name=".ReminderReceiver"/>

Then set reminder to alarm manager.

 public void setReminder(Context context,Class<?> cls,int sec)
{
    Intent intent = new Intent(context, cls);
        intent.putExtra("TIME",sec);
    PendingIntent pendingIntent = PendingIntent.getBroadcast(context, sec, intent,
            PendingIntent.FLAG_ONE_SHOT);/* Find more about flags: https://developer.android.com/reference/android/app/PendingIntent */

    AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
    am.set( AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (sec * 1000), pendingIntent );//Add time in milliseconds. if you want to minute or hour mutiply by 60.. For ex: You want to trigger 5 Min then here you need to change 5 * 60 * 1000


}

Finally set your reminder

setReminder(_Context,ReminderReceiver.class,time);

Updated

For support android version 8.0 and above you have to create notification channel. Find more here Manage Channels

Add this in above code:

 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        CharSequence name = context.getString(R.string.channel_name);
        String description = context.getString(R.string.channel_description);
        int importance = NotificationManager.IMPORTANCE_DEFAULT;
        NotificationChannel channel = new NotificationChannel("my_channel_01", name, importance);
        channel.setDescription(description);
        // Register the channel with the system; you can't change the importance
        // or other notification behaviors after this
        notificationManager.createNotificationChannel(channel);
    }

Note use drawable for small icons not use mipmap or adaptive icons.Android Oreo Notification Crashes System UI

To Cancel the scheduled notification

 public void cancelReminder(Context context,Class<?> cls)
{
    Intent intent1 = new Intent(context, cls);
    intent1.putExtra("TIME",time);
    PendingIntent pendingIntent = PendingIntent.getBroadcast(context,
            time, intent1, PendingIntent.FLAG_ONE_SHOT);
    AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);

    if(pendingIntent != null) {
        am.cancel(pendingIntent);
    }
}

And use above method to delete

cancelReminder(_Context,ReminderReceiver.class);

Note: _Context should be same as used in setreminder() method

Hi, I've followed your code. I do not get notifications though. I uploaded a RAR of my project, could you please check what I did wrong? Thank you. https://drive.google.com/open?id=1lhCIxLpF_JSvsBa_a-fu1X_ZfAUpqGrW — Erbez, Sep 05 '18 at 08:38
The floating action button has the set `setReminder(_Context,ReminderReceiver.class,time);` in it — Erbez, Sep 05 '18 at 08:40
`minSdkVersion 22`, `targetSdkVersion 27` and `compileSdkVersion 27`. I am testing on a Huawei P10 with android 8. — Erbez, Sep 05 '18 at 08:46
For me its working i change minapi 21 for checking... Its working — Mohamed Mohaideen AH, Sep 05 '18 at 08:51
I tested your code only its working fine.. [see here](https://i.stack.imgur.com/yPegr.gif) — Mohamed Mohaideen AH, Sep 05 '18 at 08:54
I changed it to min `minSdkVersion 21` and still not. I wonder why. — Erbez, Sep 05 '18 at 08:56
Check with emulator or other device if you have may be device is problem.. — Mohamed Mohaideen AH, Sep 05 '18 at 08:57
You have to work on notificaion channels from 8.0 you can find more here https://developer.android.com/guide/topics/ui/notifiers/notifications#ManageChannels — Mohamed Mohaideen AH, Sep 05 '18 at 09:09
I just wanted to ask, will this last as long as the app is installed, so if I put the notification for 3 months later, will it show 3 months later? — Erbez, Sep 05 '18 at 12:37
Yes you can get notification as long as app installed also check here lifecycle of pending intent and alarm with detailed explanation http://luboganev.github.io/post/alarms-pending-intent/ — Mohamed Mohaideen AH, Sep 05 '18 at 13:12
@MohamedMohaideenAH Sorry to bother, is there a way to cancel the notification created? — Cleaven, Oct 04 '18 at 00:20
@Cleaven Yes you can check the updated code will help you..! — Mohamed Mohaideen AH, Oct 04 '18 at 07:09
@MohamedMohaideenAH Sorry it didn't work, i posted a question if you are interested :) https://stackoverflow.com/questions/52645365/disable-stored-reminder-alarmmanager-type — Cleaven, Oct 04 '18 at 11:17
@MohamedMohaideenAH Hi, I just wanted to know which part of the notification opens my app, if I clear all notifications, the app opens, I don't want that. — Erbez, Oct 22 '18 at 19:44
@Erbez You should aware of pending intent lifecycle make sure you cancel also the pending intent after cancel alarm manager intent. Find more here http://luboganev.github.io/post/alarms-pending-intent/ — Mohamed Mohaideen AH, Oct 23 '18 at 06:43

score 2 · Answer 2 · answered Sep 05 '18 at 07:21

I suggest you read Notifications Overview. This well help you to understand how notification works.

To now build the notification, here is the Here is the official documentation for notification.

Read and understand. When you encounter any problem then, you can come back here for the solution.

How to send notification without being online?

2 Answers2

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