Question

I have to submit my mini project. I write a class to get the user location. I want to know if there is any technical problem in my approach or not. It works fine. I am Using a Handler to get the location continuously.

Main.java

public class Main extends Activity {

LocationTracker lt;
TextView tv;
Handler handler = new Handler();
Runnable locationRunner = new Runnable() {

    @Override
    public void run() {
        if (lt.canGetLocation()) {
            tv.setText(lt.getLatitude() + " " + lt.getLongitude());
        }
        handler.postDelayed(this, 1000);
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    lt = new LocationTracker(this);
    Toast.makeText(
            this,
            "GPS: " + lt.isGPSEnabled() + "\nNetwork: "
                    + lt.isNetworkEnabled() + "\nCanGetLocation: "
                    + lt.canGetLocation(), Toast.LENGTH_LONG).show();
    tv = (TextView) findViewById(R.id.textView1);
}

@Override
protected void onResume() {
    super.onResume();
    handler.postDelayed(locationRunner, 1000);
}

@Override
protected void onDestroy() {
    super.onDestroy();
    handler.removeCallbacks(locationRunner);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}

}

LocationTracker.java

public class LocationTracker implements LocationListener {

private Context context;
private boolean isGPSEnabled;
private boolean isNetworkEnabled;
private boolean isTracking;
private Location location;
private LocationManager locationManager;

public LocationTracker(Context context) {
    this.context = context;
    locationManager = (LocationManager) context
            .getSystemService(context.LOCATION_SERVICE);
    isNetworkEnabled = locationManager
            .isProviderEnabled(LocationManager.NETWORK_PROVIDER);
    isGPSEnabled = locationManager
            .isProviderEnabled(LocationManager.GPS_PROVIDER);
    if (!isNetworkEnabled && !isGPSEnabled) {
        isTracking = false;
    } else {
        isTracking = true;
    }

    if (isGPSEnabled) {
        locationManager.requestLocationUpdates(
                LocationManager.GPS_PROVIDER, 0, 0, this);
    } else if (isNetworkEnabled) {
        locationManager.requestLocationUpdates(
                LocationManager.NETWORK_PROVIDER, 0, 0, this);
    }

}

public double getLatitude() {
    if (location != null) {
        return location.getLatitude();
    } else {
        return 0.00;
    }
}

public double getLongitude() {
    if (location != null) {
        return location.getLongitude();
    } else
        return 0.00;
}

public boolean canGetLocation() {
    return isTracking;
}

public boolean isGPSEnabled() {
    return isGPSEnabled;
}

public boolean isNetworkEnabled() {
    return isNetworkEnabled;
}

@Override
public void onLocationChanged(Location arg0) {
    location = arg0;
}

@Override
public void onProviderDisabled(String arg0) {
}

@Override
public void onProviderEnabled(String arg0) {
}

@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {

}

}

`

Answer 1

Yeah, As I see it, 2 things are wrong.

1. Don’t check for availability to requestLocationUpdates.
2. Instead listen to DATA connection changes and removeUpdates, and requestLocationUpdates.

Sample code

//OnCreate

tm = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
    tm.listen(new NetworkConnectionState(this.getApplicationContext()),
            PhoneStateListener.LISTEN_DATA_CONNECTION_STATE 
| PhoneStateListener.LISTEN_CELL_LOCATION );

//Your listener

public void onDataConnectionStateChanged(int state, int networkType) {
        // We have changed protocols, for example we have gone from HSDPA to
        // GPRS
        // HSDPA is an example of a 3G connection
        // GPRS is an example of a 2G connection
        if (state == TelephonyManager.DATA_CONNECTED) {
        }
        else {
        }
    }

Edit :
Dont forget to update your connection / disconnection on onProviderDisabled and onProviderEnabled in your LocationListeners