Alarm Manager don't work

Question

I Start the Alarm Manager in MainActivity to set the Time for my Receiver (lockScreenReeiver), first it worked but suddenly it doesn't anymore.

      Calendar cur_cal = new GregorianCalendar();
      cur_cal.setTimeInMillis(System.currentTimeMillis());//set the current time and date for this calendar

      Calendar cal = new GregorianCalendar();
      cal.add(Calendar.DAY_OF_YEAR, cur_cal.get(Calendar.DAY_OF_YEAR));
      cal.set(Calendar.HOUR_OF_DAY, 10);
      cal.set(Calendar.MINUTE, 58);
      cal.set(Calendar.SECOND, cur_cal.get(Calendar.SECOND));
      cal.set(Calendar.MILLISECOND, cur_cal.get(Calendar.MILLISECOND));
      cal.set(Calendar.DATE, cur_cal.get(Calendar.DATE));
      cal.set(Calendar.MONTH, cur_cal.get(Calendar.MONTH));

      Intent intent = new Intent(MainActivity.this, lockScreenReeiver.class);
      PendingIntent pintent = PendingIntent.getService(MainActivity.this, 0, intent, 0);
      AlarmManager alarm = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
      alarm.setRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), 0, pintent);

Answer 1

If the phone is in sleep state, you will have to wake it up.

Try this:

A small example:

This is working code. It wakes CPU every 10 minutes until the phone turns off.

Add to Manifest.xml:

...
<uses-permission android:name="android.permission.WAKE_LOCK"></uses-permission>
...
<receiver  android:process=":remote" android:name="Alarm"></receiver>
...

Code:

    package YourPackage;
    import android.app.AlarmManager;
    import android.app.PendingIntent;
    import android.content.BroadcastReceiver;
    import android.content.Context;
    import android.content.Intent;
    import android.os.PowerManager;
    import android.widget.Toast;

    public class Alarm extends BroadcastReceiver 
    {    
         @Override
         public void onReceive(Context context, Intent intent) 
         {   
             PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
             PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "");
             wl.acquire();

             // Put here YOUR code.
             Toast.makeText(context, "Alarm !!!!!!!!!!", Toast.LENGTH_LONG).show(); // For example

             wl.release();
         }

     public void SetAlarm(Context context)
     {
         AlarmManager am=(AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
         Intent i = new Intent(context, Alarm.class);
         PendingIntent pi = PendingIntent.getBroadcast(context, 0, i, 0);
         am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), 1000 * 60 * 10, pi); // Millisec * Second * Minute
     }

     public void CancelAlarm(Context context)
     {
         Intent intent = new Intent(context, Alarm.class);
         PendingIntent sender = PendingIntent.getBroadcast(context, 0, intent, 0);
         AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
         alarmManager.cancel(sender);
     }
 }

Set Alarm from Service:

package YourPackage;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.IBinder;

public class YourService extends Service
{
    Alarm alarm = new Alarm();
    public void onCreate()
    {
        super.onCreate();       
    }

    public void onStart(Context context,Intent intent, int startId)
    {
        alarm.SetAlarm(context);
    }

    @Override
    public IBinder onBind(Intent intent) 
    {
        return null;
    }
}

If you want set alarm repeating at phone boot time:

Add permission to Manifest.xml:

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"></uses-permission>
...
<receiver android:name=".AutoStart">
    <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED"></action>
    </intent-filter>
</receiver>
...

And create new class:

package YourPackage;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;

public class AutoStart extends BroadcastReceiver
{   
    Alarm alarm = new Alarm();
    @Override
    public void onReceive(Context context, Intent intent)
    {   
        if (intent.getAction().equals("android.intent.action.BOOT_COMPLETED"))
        {
            alarm.SetAlarm(context);
        }
    }
}