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Want to write a code to only send notification at certain time, but somehow the alarmManager is not working and it shows some errors

Not sending notification at selected time, when I ran my code, directly showed notification
and showed error as well
Here is the error message: E/NotificationManager: notifyAsUser: tag=null, id=12345, user=UserHandle{0}
I thought the error message was due to Build.VERSION.SDK_INT, but after adding that, the error message is still there.
Place all of these under onCreate:
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 13);
calendar.set(Calendar.MINUTE,9)
;
Intent intent = new Intent ();
intent.setAction("com.example.Broadcast");
PendingIntent contentIntent = PendingIntent.getBroadcast(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
// PendingIntent alarmIntent = PendingIntent.getBroadcast(this,0, intent,0);
AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), AlarmManager.INTERVAL_DAY, contentIntent);
and here is the extend.
public class wakeReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
setNotification(context);
}
protected void setNotification(Context context){
PendingIntent contentIntent = PendingIntent.getActivity(context, 0,
new Intent(context, MainActivity.class), 0);
String ChannelId = "12345";
int uniID = 12345;
NotificationCompat.Builder builder = new NotificationCompat.Builder(context,ChannelId )
.setSmallIcon(R.mipmap.ic_launcher_round)
.setContentTitle("Hi")
.setAutoCancel(true)
.setWhen(System.currentTimeMillis())
.setContentText("Please Rate.");
builder.setContentIntent(contentIntent);
//
// Send notification to your device
NotificationManager manager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
builder.setChannelId("com.myApp");
}
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
NotificationChannel channel = new NotificationChannel(
"com.myApp",
"My App",
NotificationManager.IMPORTANCE_DEFAULT
);
if (manager != null) {
manager.createNotificationChannel(channel);
}
}
manager.notify(uniID, builder.build());
}
}
Can someone please help me with this?

You are very confused.
In your code you call NotificationManager.notify(). This will show the Notification immediately.
You do:
Intent intent = new Intent(this, MainActivity.class);
PendingIntent alarmIntent = PendingIntent.getBroadcast(this,0, intent,0);
This won't work. You have created a PendingIntent which will be sent via broadcast using an Intent that is for an Activity! What do you want to happen? Do you want an Activity to be launched or do you want a BroadcastReceiver to be triggered?
I think what you want to do is as follows:
Create an Intent for a BroadcastReceiver, wrap that in a PendingIntent using getBroadcast() and pass that to the AlarmManager so that the broadcast Intent will be set at some future time.
Create a class that extends BroadcastReceiver. In onReceive() create the Notification and call NotificationManager.notify() to post the Notification. In the Notification you can set a PendingIntent that opens your Activity so that if the user clicks on the Notification your Activity will be launched. To do this, call PendingIntent.getActivity() and pass an Intent that contains MainActivity.class.

Android Studio - Trouble setting off notifications with broadcast receiver

So my program is supposed to set off a notification a few hours after the application has been stopped (minutes are being used just now for testing). It does this, however the problem with it is that if the code is executed a second time before a notification has been pushed, then no notification is pushed at all.
Override
public void onStop() {
super.onStop();
Calendar calendar = Calendar.getInstance();
int alarmTime = (calendar.get(Calendar.MINUTE)) + 3;
calendar.set(Calendar.MINUTE,alarmTime);
Intent intent3 = new Intent(getApplicationContext(),timeReceiver.class);
PendingIntent pendingIntent3 = PendingIntent.getBroadcast(getApplicationContext(),100,intent3,PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,calendar.getTimeInMillis(),AlarmManager.INTERVAL_DAY,pendingIntent3);
}
#Override
protected void onRestart() {
super.onRestart();
//this.onCreate(null);
}
This is what my broadcast receiver class looks like...
public class timeReceiver extends BroadcastReceiver{
#Override
public void onReceive(Context context, Intent intent) {
NotificationManager notificationManager =(NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
Intent repeating_intent = new Intent(context, RepeatingActivity.class);
repeating_intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
PendingIntent pendingIntent = PendingIntent.getActivity(context,100,repeating_intent,PendingIntent.FLAG_UPDATE_CURRENT);
NotificationCompat.Builder builder = new NotificationCompat.Builder(context);
builder.setContentIntent(pendingIntent);
builder.setSmallIcon(android.R.drawable.arrow_up_float);
builder.setContentTitle("Timer Notification");
builder.setContentText("blaaah blaaah blah");
builder.setAutoCancel(true);
notificationManager.notify(100,builder.build());
}
}
My expectation is that the alarm would reset and trigger 3 minutes after the last execution of the onStop() method, but this does not happen. I don't really understand why it doesn't, if anyone could give me insight/ a possible solution I would be grateful. Also the SDK version is 24.

You can schedule your notification with NotificationCompat.Builder#setWhen(long), no need for alarm manager.

int notification1Id = 56748;
Calendar calendar = Calendar.getInstance();
int alarmTime = (calendar.get(Calendar.MINUTE)) + 2;
calendar.set(Calendar.MINUTE,alarmTime);
long timeMs = calendar.getTimeInMillis();
Intent intent = new Intent(this, MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
final PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);
// Build notifications
NotificationCompat.Builder builder = new NotificationCompat.Builder(this, channelID);
builder.setContentIntent(pendingIntent);
builder.setSmallIcon(android.R.drawable.arrow_up_float);
builder.setContentTitle("It's been a while...");
builder.setContentText("Remember to keep track of your calories using the calorie counter");
builder.setAutoCancel(true);
builder.setWhen(timeMs);
NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(notification1Id, builder.build());

AlarmManager alarm goes off immediately and ignores delay

I'm trying to do a simple Alarm manager, and although I'm adding a delay of 5 second,
the alarm in my phone goes off immediately.
I'm aware that in my receiver the alarm says to go off now,
but I understood that you set the delay to when you want it to go off at the pending intent.
what am I doing wrong ?
here is my alarm intent:
AlarmManager manager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent (AlarmClockScreen.this, AlarmNotificationReciever.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(getApplicationContext(), 0, intent, 0);
manager.set(AlarmManager.RTC_WAKEUP, SystemClock.elapsedRealtime()+5000,pendingIntent);
and here is my Receiver
public class AlarmNotificationReciever extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
NotificationCompat.Builder builder = new NotificationCompat.Builder(context);
builder.setAutoCancel(true)
.setDefaults(Notification.DEFAULT_ALL)
.setWhen(System.currentTimeMillis())
.setSmallIcon(android.R.mipmap.sym_def_app_icon)
.setContentTitle("Alarm TITLE")
.setContentText("I will finish, What you started")
.setDefaults(Notification.DEFAULT_LIGHTS | Notification.DEFAULT_SOUND)
.setContentInfo("Info");
NotificationManager notificationManager = (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(1,builder.build());
}
}

fixed it by adding
Calendar time = Calendar.getInstance();
time.setTimeInMillis(System.currentTimeMillis());
time.add(Calendar.SECOND, 30);
and then using time.getTimeInMillis()

How to run a background service to give alerts in android?

I am working on an android application but the problem is that I have to alert user through a message on notification bar which will occur after ten(10) days ,like in candy crush game it gives alert of full lives after some hours. I am a beginner in android so I am confused about the implementation of this scenario. Please guide me of its implementation with code.

You can do so with the AlarmManager and the BroadcastReceiver
AlarmManager
Intent myIntent = new Intent(this, TimeAlarm.class);
pendingIntent = PendingIntent.getService(AndroidAlarmService.this, 0, myIntent, 0);
AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.add(Calendar.DAY_OF_MONTH, 10);
alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
BroadcastReceiver
public class TimeAlarm extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent paramIntent) {
// Request the notification manager
NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
// Create a new intent which will be fired if you click on the notification
Intent intent = new Intent("android.intent.action.VIEW");
// Attach the intent to a pending intent
PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
// Create the notification
Notification notification = new Notification(R.drawable.icon, "Something new!"), System.currentTimeMillis());
notification.setLatestEventInfo(context, "Something new!", "Description",pendingIntent);
// Fire the notification
notificationManager.notify(1, notification);
}
}

Notification sent to user at a specific time Android

I'm trying to send a notification to a user at a specific time using an Alarm Manager. Basically, nothing happens at all and to me the code looks fine. My code for the Alarm Manager is below:
/** Notify the user when they have a task */
public void notifyAtTime() {
Intent myIntent = new Intent(PlanActivity.this , Notification.class);
AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
PendingIntent pendingIntent = PendingIntent.getService(PlanActivity.this, 0, myIntent, 0);
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 12);
calendar.set(Calendar.MINUTE, 17);
calendar.set(Calendar.SECOND, 00);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), 24*60*60*1000 , pendingIntent);
}
The code for the notification, which is in the "Notification" class is below:
public class Notification extends Service {
#Override
public void onCreate() {
Toast.makeText(this, "Notification", Toast.LENGTH_LONG).show();
Intent intent = new Intent(this,PlanActivity.class);
PendingIntent pending = PendingIntent.getActivity(this, 0, intent, 0);
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(
this).setSmallIcon(R.drawable.ic_launcher)
.setContentTitle("Football")
.setContentText("Don't forget that you have Football planned!")
.setContentIntent(pending);
NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
manager.notify(0, mBuilder.build());
}
#Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
}
The Toast which is set in the Notification class also doesn't come up. I don't know if it's something really silly that I'm missing but any help would be greatly appreciated! :)

This is your receiver class :
public class OnetimeAlarmReceiver extends BroadcastReceiver {
public void onReceive(Context context, Intent intent) {
//Toast.makeText(context, "Repeating Alarm worked.", Toast.LENGTH_LONG).show();
// try here
// prepare intent which is triggered if the
// notification is selected
Intent intent = new Intent(this, NotificationReceiver.class);
PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent, 0);
// build notification
// the addAction re-use the same intent to keep the example short
Notification n = new Notification.Builder(this)
.setContentTitle("New mail from " + "test#gmail.com")
.setContentText("Subject")
.setSmallIcon(R.drawable.icon)
.setContentIntent(pIntent)
.setAutoCancel(true)
.addAction(R.drawable.icon, "Call", pIntent)
.addAction(R.drawable.icon, "More", pIntent)
.addAction(R.drawable.icon, "And more", pIntent).build();
NotificationManager notificationManager =
(NotificationManager) getSystemService(NOTIFICATION_SERVICE);
notificationManager.notify(0, n);
}
}
In Second Activity to set Alerm :
private void setAlarm(){
Intent intent = new Intent(this, OnetimeAlarmReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, REQUEST_CODE, intent, 0);
AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
alarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + alarm_time , pendingIntent);
System.out.println("Time Total ----- "+(System.currentTimeMillis()+total_mili));
}
I would like to recommend this tutorial How to send notification

Try to put your notification code in the onStartCommand function instead of onCreate.

Writing the alarmmanager code in the onCreate method of the LAUNCHER activity of the app solved my problem