getting geolocation after 20 seconds

Question

i am making an android app using geo-location in android. i am using the location manager for getting the geo-location coordinates.

   locationManager.requestLocationUpdates(provider, 0, 0, this);
   Location location = locationManager.getLastKnownLocation(provider);

and using the postDelayed() function for continuously called the getLastKnownLocation() for the geo-location. and set the interval timing 1000 (1 sec). but i get the response after 20 seconds. Can any body explain me why it happens. i am new in android.

Answer 1

Note that you shouldn't be calling getLastKnownLocation() every second if you have a Location Listener set up (which it looks like you do). Just use the latest values given in the onLocationChanged() callback.

This code works for me, it registers a Location Listener, which updates the lat/lon member variables, and then the Runnable runs with an initial interval of one second, and then every five seconds (5000 milliseconds) and displays the most current location value.

I put in a Toast to make sure that the Runnable is being run every 5 seconds by handler.postDelayed().

Here is the full Activity code:

import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Handler;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;


public class MainActivity extends ActionBarActivity implements LocationListener {

    LocationManager locationManager;
    Handler handler;
    Location location;

    double latitude;
    double longitude;

    TextView lat;
    TextView lon;

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

        handler = new Handler();

        lat = (TextView) findViewById(R.id.latitudeTextView);
        lon = (TextView) findViewById(R.id.longitudeTextView);

        locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, this);
        location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
        if (location != null){
            latitude = location.getLatitude();
            longitude = location.getLongitude();
        }

        handler.postDelayed(runLocation, 1000);
    }

    public Runnable runLocation = new Runnable(){
        @Override
        public void run() {
            lat.setText(String.valueOf(latitude));
            lon.setText(String.valueOf(longitude));
            Toast.makeText(MainActivity.this, "location check", Toast.LENGTH_SHORT).show();

            MainActivity.this.handler.postDelayed(MainActivity.this.runLocation, 5000);
        }
    };


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

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onLocationChanged(Location location) {
        latitude = location.getLatitude();
        longitude = location.getLongitude();
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {

    }

    @Override
    public void onProviderEnabled(String provider) {

    }

    @Override
    public void onProviderDisabled(String provider) {

    }
}

Edit:

As an alternative, you could take out the use of postDelayed(), and just use the onLocationChanged() events.

In the example below, I used both NETWORK_PROVIDER and GPS_PROVIDER.

This is needed in the AndroidManifest.xml:

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

Here is the modified code, which registers the Activity as a Location Listener for both Network location callbacks and GPS location callbacks, with a minimum time interval of one second. Note that events can come in at a greater interval than one second, but with the GPS location enabled, I saw them coming in every second (it was taking longer with only Network location enabled).

public class MainActivity extends ActionBarActivity implements LocationListener {

    LocationManager locationManager;
    Handler handler;
    Location location;

    double latitude;
    double longitude;

    TextView lat;
    TextView lon;

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

        handler = new Handler();

        lat = (TextView) findViewById(R.id.latitudeTextView);
        lon = (TextView) findViewById(R.id.longitudeTextView);

        locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000, 0, this);
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 0, this);
        location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
        if (location != null){
            latitude = location.getLatitude();
            longitude = location.getLongitude();
        }

        //handler.postDelayed(runLocation, 1000);
    }
/*
    public Runnable runLocation = new Runnable(){
        @Override
        public void run() {
            lat.setText(String.valueOf(latitude));
            lon.setText(String.valueOf(longitude));
            Toast.makeText(MainActivity.this, "location check", Toast.LENGTH_SHORT).show();

            MainActivity.this.handler.postDelayed(MainActivity.this.runLocation, 5000);
        }
    };
*/

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

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onLocationChanged(Location location) {
        latitude = location.getLatitude();
        longitude = location.getLongitude();

        lat.setText(String.valueOf(latitude));
        lon.setText(String.valueOf(longitude));
        Toast.makeText(MainActivity.this, "location changed: " + latitude + " " + longitude, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {

    }

    @Override
    public void onProviderEnabled(String provider) {

    }

    @Override
    public void onProviderDisabled(String provider) {

    }
}

Answer 2

Use this class as common class.

package com.ibl.commonClass;
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.util.Log;

public class GPSTracker extends Service implements LocationListener {

private final Context mContext;

// flag for GPS status
boolean isGPSEnabled = false;

// flag for network status
boolean isNetworkEnabled = false;

// flag for GPS status
boolean canGetLocation = false;

Location location; // location
double latitude; // latitude
double longitude; // longitude

// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters

// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute

// Declaring a Location Manager
protected LocationManager locationManager;

public GPSTracker(Context context) {
    this.mContext = context;
    getLocation();
}

public Location getLocation() {
    try {
        locationManager = (LocationManager) mContext
                .getSystemService(LOCATION_SERVICE);

        // getting GPS status
        isGPSEnabled = locationManager
                .isProviderEnabled(LocationManager.GPS_PROVIDER);

        // getting network status
        isNetworkEnabled = locationManager
                .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        if (!isGPSEnabled && !isNetworkEnabled) {
            // no network provider is enabled
        } else {
            this.canGetLocation = true;
            // First get location from Network Provider
            if (isNetworkEnabled) {
                locationManager.requestLocationUpdates(
                        LocationManager.NETWORK_PROVIDER,
                        MIN_TIME_BW_UPDATES,
                        MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                Log.d("Network", "Network");
                if (locationManager != null) {
                    location = locationManager
                            .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                    if (location != null) {
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
                    }
                }
            }
            // if GPS Enabled get lat/long using GPS Services
            if (isGPSEnabled) {
                if (location == null) {
                    locationManager.requestLocationUpdates(
                            LocationManager.GPS_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                    Log.d("GPS Enabled", "GPS Enabled");
                    if (locationManager != null) {
                        location = locationManager
                                .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                        if (location != null) {
                            latitude = location.getLatitude();
                            longitude = location.getLongitude();
                        }
                    }
                }
            }
        }

    } catch (Exception e) {
        e.printStackTrace();
    }

    return location;
}

/**
 * Stop using GPS listener Calling this function will stop using GPS in your
 * app
 * */
public void stopUsingGPS() {
    if (locationManager != null) {
        locationManager.removeUpdates(GPSTracker.this);
    }
}

/**
 * Function to get latitude
 * */
public double getLatitude() {
    if (location != null) {
        latitude = location.getLatitude();
    }

    // return latitude
    return latitude;
}

/**
 * Function to get longitude
 * */
public double getLongitude() {
    if (location != null) {
        longitude = location.getLongitude();
    }

    // return longitude
    return longitude;
}

/**
 * Function to check GPS/wifi enabled
 * 
 * @return boolean
 * */
public boolean canGetLocation() {
    return this.canGetLocation;
}

/**
 * Function to show settings alert dialog On pressing Settings button will
 * lauch Settings Options
 * */
public void showSettingsAlert() {
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

    // Setting Dialog Title
    alertDialog.setTitle("GPS is settings");

    // Setting Dialog Message
    alertDialog
            .setMessage("GPS is not enabled. Do you want to go to settings menu?");

    // On pressing Settings button
    alertDialog.setPositiveButton("Settings",
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    Intent intent = new Intent(
                            Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                    mContext.startActivity(intent);
                }
            });

    // on pressing cancel button
    alertDialog.setNegativeButton("Cancel",
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    dialog.cancel();
                }
            });

    // Showing Alert Message
    alertDialog.show();
}

@Override
public void onLocationChanged(Location location) {
}

@Override
public void onProviderDisabled(String provider) {
}

@Override
public void onProviderEnabled(String provider) {
}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}

@Override
public IBinder onBind(Intent arg0) {
    return null;
}

}

and this code put at in your activity in oncreate Method

GPSTracker gps;
gps = new GPSTracker(NearMeActivity.this);

    if (gps.canGetLocation()) {

        latitude = gps.getLatitude();
        longitude = gps.getLongitude();

        // Toast.makeText(
        // getApplicationContext(),
        // "Your Location is - \nLat: " + latitude + "\nLong: "
        // + longitude, Toast.LENGTH_LONG).show();
    } else {
        gps.showSettingsAlert();
    }

    Log.e("latlong", "" + latitude + "" + longitude);