CODEWITHSUNDEEP
android
eric_spittle
eric_spittle

Reputation: 124

Stopping a Location Listener

I Need to stop the location listener updates. I know that in order to stop a location listener I need to call locationManager.removeUpdates(LocationListener) but I keep getting an error of MyLocationListener cannot be resolved to a variable

Here is the code I have:

import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;

import android.app.Activity;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class GetCoords extends Activity {

    private static final long MINIMUM_DISTANCE_CHANGE_FOR_UPDATES = 1; //in Meters
    private static final long MINIMUM_TIME_BETWEEN_UPDATES = 10000; //in Milliseconds

    protected LocationManager locationManager;

    protected Button getLocationButton;
    protected Button stopLocationButton;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_get_coords);

        getLocationButton = (Button) findViewById(R.id.get_location_button);
        stopLocationButton = (Button) findViewById(R.id.stop_location_button);

        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        locationManager.requestLocationUpdates(
                LocationManager.GPS_PROVIDER,
                MINIMUM_TIME_BETWEEN_UPDATES,
                MINIMUM_DISTANCE_CHANGE_FOR_UPDATES,
                new MyLocationListener()
        );

        getLocationButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                showCurrentLocation();
            //String message = "GPS Service Started";
            Toast.makeText(GetCoords.this, "GPS Service Started", Toast.LENGTH_SHORT).show();
        }
    });
    stopLocationButton.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            stopMyLocation();
            //locationManager = null;
            //stopCurrentLocation();
            Toast.makeText(GetCoords.this, "GPS Service Stopped", Toast.LENGTH_SHORT).show();
        }
    });
        }

protected void stopMyLocation() {
    locationManager.removeUpdates(MyLocationListener);
            locationManager = null;
}

I don't understand what I am doing wrong, every example I have seen of how to stop GPS updates makes me think that my code under stopMyLocation() is correct. I have tried it inside the stopLocationButton click listener, in its current location, pretty much everywhere and it keeps telling me that MyLocationListener is incorrect.

Upvotes: 0

Views: 2063

Answers (5)

JenniferG
JenniferG

Reputation: 602

I too was having the same issue. I think my problem was similar to the issues mentioned above as far as different instances of the listener being created. What I ended up doing was creating a static listener and creating a singleton method to prevent another instance of the listener from being created. The code looks something like this: 

 static LocationListener mLocationListener = null;

 public LocationListener getLocationListener(){
    if(mLocationListener==null)
       mLocationListener = new MyLocationListener();
    return mLocationListener;
 }

Then I used it this way 

locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000 * 2, 0, getLocationListener());

locationManager.removeLocationUpdates(getLocationListener());

You could do the same thing with the locationmanager if necessary but I didnt have too. Hope this helps!

Upvotes: 0

joel
joel

Reputation: 480

You get the error because the stopMyLocation() function passes the unknown variable MyLocationListener to removeUpdates:

locationManager.removeUpdates(MyLocationListener);

To pass an existing variable to removeUpdates you have define an object variable of the MyLocationListener class which is accessible in the onCreate() and the stopMyLocation() function.

private MyLocationListener locationListener;

The locationListener variable can be instantiated in the onCreate() function and has to be used to call the requestLocationUpdates(...) function.

locationListener = new MyLocationListener();

locationManager.requestLocationUpdates(
            LocationManager.GPS_PROVIDER,
            MINIMUM_TIME_BETWEEN_UPDATES,
            MINIMUM_DISTANCE_CHANGE_FOR_UPDATES,
            locationListener
    );

Upvotes: 1

varevarao
varevarao

Reputation: 2186

You have initialized MyLocationListener, but not assigned it to a variable to be used later. How would Java know which instance of MyLocationListener class you're referring to in the removeUpdates() call?

  1. Make a class variable LocationListener abc;

  2. In the onCreate() method add the line abc = new MyLocationListener(); before you register for updates.

  3. Pass this in your requestLocationUpdates() method.

  4. call removeUpdates(abc) in your stopMyLocation() method.

Upvotes: 1

dymmeh
dymmeh

Reputation: 22306

You need to assign your location listener to a field.. as in

protected MyLocationListener listener;

Then in your onCreate:

listener = new MyLocationListener();

locationManager.requestLocationUpdates(
                LocationManager.GPS_PROVIDER,
                MINIMUM_TIME_BETWEEN_UPDATES,
                MINIMUM_DISTANCE_CHANGE_FOR_UPDATES,
                listener);

your unregister will then look like

 locationManager.removeUpdates(listener);

Upvotes: 3

Sam
Sam

Reputation: 86948

Save a reference to your LocationListener:

protected LocationManager locationManager;
protected MyLocationListener myLocationListener = new MyLocationListener();

Change this:

    locationManager.requestLocationUpdates(
            LocationManager.GPS_PROVIDER,
            MINIMUM_TIME_BETWEEN_UPDATES,
            MINIMUM_DISTANCE_CHANGE_FOR_UPDATES,
            myLocationListener
    );

Now you can cancel it with:

locationManager.removeUpdates(myLocationListener);

Upvotes: 2

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