I am trying to create a background service that updates the current gps position. I am getting a NullPointerException
at line LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
HomeActivity launches a service
startService(new Intent(getApplicationContext(), ForHire.class));
Service (ForHire) creates a TimerTask Updates
public class ForHire extends Service {
...
private Timer getUpdatesNow = new Timer();
private Updates updates = new Updates(getUpdatesNow);
@Override
public void onCreate() {
...
getUpdatesNow.schedule(updates, God.KM20TIME);
Log.v("Taxeeta", "Notification created");
}
private class Updates extends TimerTask implements LocationListener {
private Timer getUpdatesNow;
public Updates(Timer newGetUpdatesNow) {
super();
getUpdatesNow = newGetUpdatesNow;
LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER,
God.KM20TIME, God.KM20DISTANCE, (LocationListener) this);
}
public void run() {
...
//do some cleanup
}
@Override
public void onLocationChanged(Location location) {
Log.v("Taxeeta", "Location changed");
// do a update of the current location.
}
The first issue is that I get that NullPointerException.
Second issue is that onLocationChanged is never called if I comment out LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, God.KM20TIME, God.KM20DISTANCE, (LocationListener) this);
these 2 lines.
My Manifest
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CALL_PHONE" />
<application ...>
...
<uses-library android:name="com.google.android.maps" />
</application>
What am I missing here ?
Edit : Values of KM20TIME = 5000
(5seconds), and KM20DISTANCE = 1
(1meter). Apart from the fix's below, I walked out of my house, got GPS enabled and walked from one corner of my balcony to the other. I noticed that my gps (LSB) changed as I walked from one corner to the other every 5 seconds.
The earliest you can call new Updates(getUpdatesNow);
is inside your Service's onCreate()
method. The simple reason is that getSystemService()
requires a valid Context which doesn't exist before entering onCreate()
.
Try:
private Timer getUpdatesNow;
private Updates updates;
@Override
public void onCreate() {
...
getUpdatesNow = new Timer();
updates = new Updates(getUpdatesNow);
// Acquire a reference to the system Location Manager
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
// Define a listener that responds to location updates
Location location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
Toast.makeText(getBaseContext(),
"Last Location is found..",
Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getBaseContext(),
"Last Location is not found..",
Toast.LENGTH_LONG).show();
}
LocationListener locationListener = new LocationListener() {
public void onStatusChanged(String provider,
int status, Bundle extras) {
}
public void onProviderEnabled(String provider) {
Toast.makeText(getApplicationContext(),
"Gps Enabled", Toast.LENGTH_SHORT).show();
}
public void onProviderDisabled(String provider) {
Toast.makeText(getApplicationContext(),
"Gps Disabled", Toast.LENGTH_SHORT).show();
}
@Override
public void onLocationChanged(Location location) {
Log.i("geolocation",
"lat is : " + location.getLatitude()
+ " and " + location.getLongitude()
+ "");
Toast.makeText(getBaseContext(),
"Location is Changed..", Toast.LENGTH_LONG)
.show();
}
};
// Register the listener with the Location Manager to receive location updates
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER, 0, 0,
locationListener);
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With