I'm building an Android pedometer app that sends data to a SQLite database at 30 minute intervals using AlarmManager; if the phone is off when the transfer is supposed to occur, it will do the transfer immediately when the phone is switched back on.
(30 minutes is for testing - the actual interval will be 1 week).
I was told alarms wouldn't persist unless I used "intent.action.BOOT_COMPLETED" in the manifest, so I put that as a filter for my Alarm.java class.
My code to set the alarm (in MainActivity.java) is as follows:
public void insertData(View view) {
AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
long time= System.currentTimeMillis();
Date d = new Date(time);
editor.putLong("alarmtime", time); //the next ring time for the alarm is put in SharedPreferences
editor.apply();
Intent intent = new Intent(this, Alarm.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(
this,
0,
intent,
PendingIntent.FLAG_UPDATE_CURRENT);
alarmManager.setRepeating(AlarmManager.RTC, time, AlarmManager.INTERVAL_DAY, pendingIntent);
Toast.makeText(MainActivity.this, "Alarm Set", Toast.LENGTH_LONG).show();
}
The code in the Alarm.java class (which extends BroadcastReceiver) is as follows:
Context context; //plus other declared variables
@Override
public void onReceive(Context context, Intent intent) {
this.context = context;
preferences = context.getSharedPreferences("MyPreferences", context.MODE_PRIVATE);
editor = preferences.edit();
long startedtime = preferences.getLong("alarmtime", 0); //get the next ring time
Date nextRingTime = new Date(startedtime);
AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
String action = intent.getAction();
//sometimes the onReceive() is called by the phone turning on
if (action != null && action.equals(Intent.ACTION_BOOT_COMPLETED)) {
//if phone turned on again before the alarm, just re-create the alarm for the same time, don't transfer data
Date currenttime = new Date(System.currentTimeMillis());
if ((currenttime.compareTo(nextRingTime) < 0)) {
Intent newintent = new Intent(context, Alarm.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(
context,
0,
newintent,
PendingIntent.FLAG_UPDATE_CURRENT);
alarmManager.setRepeating(AlarmManager.RTC, startedtime, AlarmManager.INTERVAL_HALF_HOUR, pendingIntent);
return;
}
else if ((currenttime.compareTo(nextRingTime) > 0)) {
//if the phone was off when the alarm was supposed to make the transfer, set the alarm to the next intended ring time and insert data to db immediately
Calendar d = Calendar.getInstance();
d.setTime(nextRingTime);
d.add(Calendar.MINUTE, 30);
long newtime = d.getTimeInMillis();
Intent newintent = new Intent(context, Alarm.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(
context,
0,
newintent,
PendingIntent.FLAG_UPDATE_CURRENT);
alarmManager.setRepeating(AlarmManager.RTC, newtime, AlarmManager.INTERVAL_HALF_HOUR, pendingIntent);
}
}
myDb = new DatabaseHelper(context);
// code for inserting data into database
//finally, update next intended ring time in SharedPreferences now that this particular transfer is done:
Calendar c = Calendar.getInstance();
c.setTime(nextRingTime);
c.add(Calendar.MINUTE, 30);
Log.v("insertdone, alarrm now", c.getTime().toString());
long nexttime = c.getTimeInMillis();
editor.putLong("alarmtime", nextime);
editor.apply();
}
Unfortunately, if the phone is off at the time of a scheduled alarm, when I turn it on afterwards, it calls onReceive() TWICE, meaning it inserts data twice.
How can this be stopped?
A solution would maybe be to use RTC_WAKEUP, but I really don't want to do that unless as an absolute last resort.
N.B. I have a separate bootBroadcastReceiver class that uses "intent.action.BOOT_COMPLETED" to restart a pedometer service, and am wondering whether having 2 different things started by the boot is causing problems...
