I search a lot and I tried several ways but I couldn't find anything that avoid my error.
I'm working on app for my learning, where is an String in my MainActivity and then I call it in my Service. I tried something like this:
This next one goes in my myService.class
//In my myService.class that extends Service
public class myService extends Service{
AlarmManager manager;
PendingIntent pintent;
String te;
@Override
public void onCreate()
{
manager = (AlarmManager)(this.getSystemService(Context.ALARM_SERVICE));
pintent = PendingIntent.getBroadcast( this, 0, new Intent("blahblah"), 0 );}
@Override
public int onStartCommand(Intent intent, int flags, int startid)
{
super.onStartCommand(intent, flags, startid);
te = intent.getStringExtra("tst"); //if I change this line to te = "something", everything goes fine
BroadcastReceiver receiver = new BroadcastReceiver() {
@Override
public void onReceive( Context context, Intent intent )
{
Toast.makeText(getApplicationContext(),te, Toast.LENGTH_SHORT).show();
}
};
this.registerReceiver(receiver, new IntentFilter("blahblah") );
// set alarm to fire 30 min and waits 2 min
manager.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime() + 1000*30*60, 1000*2*60, pintent);
return START_STICKY;}
public IBinder onBind(Intent p1)
{
// TODO: Implement this method
return null;
}
}
Here the code runs perfectly, but when I exit my App, it crashes. After 1 minute, my device shows again that my App crashes, confirming my app "successfully" ran into background. What is wrong with it? I also learned I could use IntentService instead of Service, wich one is better for long tasks and what is the difference between them ?
EDIT***
I received the following error: java.lang.NullPointerExeption. So I change this:
te = intent.getStringExtra("tst");
To this:
try { te = intent.getStringExtra("tst"); } catch(NullPointerException e) {}
When I changed it my app works with any error, but The problem is: I need to retrieve my String from my MainActivity, when I close my app my service runs without errors but my "te" String takes null valor, what can I do to "save" my String in my service, to be able to use it and keeping showing the "working" message after I close my App ? Should I use SharedPreferences ?
Hope I was clear.