I m looking for the best practice to implement a service for logging gps- or other sensor-values periodically (every 10-60 sec). The service should deal with the standby mode, when the phone goes asleep.
Any help (pseudo-code or tutorials) is very much appreciated!
It looks like it is impossible to let the orientation sensors work constantly for hours even though the device may fall asleep (refer to http://code.google.com/p/android/issues/detail?id=3708#makechanges
As soon as the display goes off, the sensors will do alike... :(
I now implemented a wakelock (needs permission)
<uses-permission android:name="android.permission.WAKE_LOCK" />
in conjunction with a timer and a broadcastreciever that will turn the display back on again. This is of course crazy for battery life but I found no other way so far.
This is my onCreate method in the service:
@Override
public void onCreate() {
mNM = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
CONTEXT = this;
PowerManager pm = (PowerManager) CONTEXT.getSystemService(Context.POWER_SERVICE);
this.mWakeLock = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP, "my tag");
mWakeLock.acquire();
Log.d(TAG, "Wakelock acquired");
// register receiver that handles screen on and screen off logic
IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
filter.addAction(Intent.ACTION_SCREEN_OFF);
BroadcastReceiver mReceiver = new ScreenReceiver();
registerReceiver(mReceiver, filter);
}
this the onStart method of the service:
@Override
public void onStart(Intent intent, int startid) {
Toast.makeText(this, "My Service Started", Toast.LENGTH_SHORT).show();
Log.d(TAG, "onStart");
boolean screenOn = intent.getBooleanExtra("screen_state", false);
if (!screenOn) {
Log.d(TAG, "Screen is on");
} else {
Log.d(TAG, "Screen is off");
Timer timer = new Timer("DigitalClock");
timer.schedule(new TimerTask() {
@Override
public void run() {
Log.d(TAG,"Waiting 1 sec for switching the screen back on again...");
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
mWakeLock = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP,
"my tag");
mWakeLock.acquire();
}
}, 1000);
mWakeLock.acquire();
}
}
and this is the BroadcastReceiver class:
public class ScreenReceiver extends BroadcastReceiver { private boolean screenOff; @Override public void onReceive(Context context, Intent intent) { if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) { screenOff = true; } else if (intent.getAction().equals(Intent.ACTION_SCREEN_ON)) { screenOff = false; } Intent i = new Intent(context, MyService.class); i.putExtra("screen_state", screenOff); context.startService(i); }}
This workaround will also do with a device UN-plugged from the debugger via USB (I first had an issue with this).
Please let me know if you have a better solution, or if there is fix in 2.3. Thanx!
