Question

I’ve this class (starts after boot of android) that executes AlarmReceiver at fixed time. I added sharedpreferences to disable and enable alarms. If I disable and re-enable alarm does not run. I need reboot emulator. Can I avoid emulator reboot? thanks!

public class AutoStart extends BroadcastReceiver {

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
    CheckboxPreference = prefs.getBoolean("checkboxPref", true);
Calendar cal4 = Calendar.getInstance(TimeZone.getDefault(), Locale.getDefault());
    cal4.set(Calendar.DATE,31);
    cal4.set(Calendar.MONTH,Calendar.DECEMBER); 
    cal4.set(Calendar.YEAR,2012);//year...
    cal4.set(Calendar.HOUR_OF_DAY, 23);  
    cal4.set(Calendar.MINUTE, 59);       
    cal4.set(Calendar.SECOND, 00);       

Intent intent2 = new Intent(context, AlarmReceiver.class);
    PendingIntent Alarm1 = PendingIntent.getBroadcast(context, 0, intent2, 0);

alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, cal4.getTimeInMillis(), DateUtils.DAY_IN_MILLIS, Alarm1);

Manifest:

<receiver android:name="AutoStart">
        <intent-filter>
        <action
        android:name="android.intent.action.BOOT_COMPLETED" />
        <category android:name="android.intent.category.HOME" />
        </intent-filter>
        </receiver>

Answer 1

First thing you’re going to want to do is make a static method that makes the Alarm put it in AutoStart:

public static modifyAlarm (Context context, boolean cancel)
{
  Calendar cal4 = Calendar.getInstance(TimeZone.getDefault(), Locale.getDefault());
  cal4.set(Calendar.DATE,31);
  cal4.set(Calendar.MONTH,Calendar.DECEMBER); 
  cal4.set(Calendar.YEAR,2012);//year...
  cal4.set(Calendar.HOUR_OF_DAY, 23);  
  cal4.set(Calendar.MINUTE, 59);       
  cal4.set(Calendar.SECOND, 00);       

  Intent intent2 = new Intent(context, AlarmReceiver.class);
  PendingIntent Alarm1 = PendingIntent.getBroadcast(context, 0, intent2, 0);

  AlarmManager alarmManager = (AlarmManager) context.getSystemService (Context.ALARM_SERVICE);
  if (cancel)
    alarmManager.cancel (Alarm1);
  else
    alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, cal4.getTimeInMillis(), DateUtils.DAY_IN_MILLIS, Alarm1);
}

Call it in AutoStart‘s onReceive() like this:

@Override
public void onReceive (Context context, Intent intent)
{
  SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);     
  makeAlarm (context, prefs.getBoolean("checkboxPref", true));
}

Now, your Preference must be part of some Activity. To keep things simple, we’ll take care of handling the Alarm in that Activity’s onPause();

@Override
protected void onPause()
{
  SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
  boolean alarmEnabled = prefs.getBoolean("checkboxPref", true);
  AutoStart.modifyAlarm (this, alarmEnabled);
  super.onPause();
}

Now when the user cancels your Alarm or re-enables it, your code takes care of that. If you call cancel on a PendingIntent, it will cancel it if it is valid or do nothing if it is not, so we do not have to worry about checking to see if the Alarm already exists.