Android PhoneStateListener: onCellLocationChanged in standby mode

Question

I'm writing an app that runs in the background as a foreground service. This service instantiates a subclass of PhoneStateListener. The PhoneStateListener creates a TelephonyService with a context object of the foreground service and then listens to cell location changes. This works perfectly while the display in on. But as soon as the display goes off, the logging of the cells doesn't work anymore.

public class gps_service extends Service
{
public static TelephonyManager p_TelephonyManager = null;
public static myPhoneStateListener p_myPhoneStateListener = null;

@Override
  public int onStartCommand(Intent intent, int flags, int startId) 
  {
  p_myPhoneStateListener = new myPhoneStateListener();
  p_TelephonyManager = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);
  p_TelephonyManager.listen(p_myPhoneStateListener, PhoneStateListener.LISTEN_CELL_LOCATION);
...

}

public class myPhoneStateListener extends PhoneStateListener
{
    public static int CurrentCellID;
    /*
    public static int current_cell_id;  
    @Override
    public void onCellLocationChanged(CellLocation p_CellLocation)
    {
       //write to log
    }

}

<uses-sdk android:minSdkVersion="3" />    
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.WAKE_LOCK" />

When phone screen is on, all working fine, but when turn screen of onCellLocationChanged event never call. Also I try GsmCellLocation currentCellLocation = (GsmCellLocation) p_TelephonyManager .getCellLocation(); by this code always return last cell id before off screen, not actual cell id.

Also I try partial_wake_lock in my service, but the same results:

private PowerManager pPowerManager = null;
private PowerManager.WakeLock pWakeLock = null;
..

@Override
public void onCreate() 
{
    super.onCreate();
    pPowerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);
    pWakeLock = pPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "No sleep");
    pWakeLock.acquire();
...
}

@Override
public void onDestroy() 
{
    if (pWakeLock != null)
        {
            pWakeLock.release();
            pWakeLock = null;
        }
...
}

Any idea what I do wrong? Testing on HTC Desire Z Android 2.2

Answer 1

This situation is screen off thus, phone goes into sleep mode. Take a look into PowerManager.

The following flags are defined, with varying effects on system power. These flags are mutually exclusive - you may only specify one of them.

Flag Value            CPU   Screen  Keyboard
PARTIAL_WAKE_LOCK      On*  Off      Off
SCREEN_DIM_WAKE_LOCK    On  Dim     Off
SCREEN_BRIGHT_WAKE_LOCK On  Bright  Off
FULL_WAKE_LOCK          On  Bright  Bright

*If you hold a partial wakelock, the CPU will continue to run, irrespective of any timers and even after the user presses the power button. In all other wakelocks, the CPU will run, but the user can still put the device to sleep using the power button.

 PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
 PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "My Tag");
 wl.acquire();
   ..screen will stay on during this section..
 wl.release();