Using GPS to get current location – Android tutorial

Today we are going to see how to get our current location from the GPS.

1. Create a new Android project called UseGps, under the folder “Firstdroid.Tutorial.Gps”

2. In order to be able to access the GPS, we will have to add the permission in

the AndroidManifest.xml file:

This is how the complete file looks like

<?xml version=“1.0″ encoding=“utf-8″?> <manifest xmlns:android=“http://schemas.android.com/apk/res/android” package=“Firstdroid.Tutorial.Gps” android:versionCode=“1″ android:versionName=“1.0″> <application android:icon=“@drawable/icon” android:label=“@string/app_name”> <activity android:name=“.UseGps” android:label=“@string/app_name”> <intent-filter> <action android:name=“android.intent.action.MAIN” /> <category android:name=“android.intent.category.LAUNCHER” /> </intent-filter> </activity> </application> <uses-permission android:name=“android.permission.ACCESS_FINE_LOCATION”></uses-permission> </manifest>

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to   Now we need add a location listener, so each time the GPS senses a new location, this callback function will be called from the android system.

To do this, we need to add the fallowing code in the OnCreate method:

/* Use the LocationManager class to obtain GPS locations */ LocationManager mlocManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE); LocationListener mlocListener = new MyLocationListener(); mlocManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 0, 0, mlocListener);

We will add our own personal Location listener, so we can override some of the functions to do what we want. In our case we will just print a message to the screen in the fallowing cases:

· onLocationChanged ( Location Update )

· onProviderDisabled ( GPS Off )

· onProviderEnabled (GPS On )

And add another mandatory method, which will do nothing.

· onStatusChanged (We are not adding nothing here).

The UseGps.java file should look as fallows:

package Firstdroid.Tutorial.Gps; 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.widget.Toast; public class UseGps extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); /* Use the LocationManager class to obtain GPS locations */ LocationManager mlocManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE); LocationListener mlocListener = new MyLocationListener(); mlocManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 0, 0, mlocListener); } /* Class My Location Listener */ public class MyLocationListener implements LocationListener { @Override public void onLocationChanged(Location loc) { loc.getLatitude(); loc.getLongitude(); String Text = “My current location is: “ + “Latitud = “ + loc.getLatitude() + “Longitud = “ + loc.getLongitude(); Toast.makeText( getApplicationContext(), Text, Toast.LENGTH_SHORT).show(); } @Override public void onProviderDisabled(String provider) { Toast.makeText( getApplicationContext(), “Gps Disabled”, Toast.LENGTH_SHORT ).show(); } @Override public void onProviderEnabled(String provider) { Toast.makeText( getApplicationContext(), “Gps Enabled”, Toast.LENGTH_SHORT).show(); } @Override public void onStatusChanged(String provider, int status, Bundle extras) { } }/* End of Class MyLocationListener */ }/* End of UseGps Activity */

Now we want to test our application, for this we have to options:

1 – We can run our application in the Phone.

2 – Run the application with the simulator.

For the second case, to simulate a location update we need to connect to the simulator by telnet, and do the fallowing:

telnet localhost 5554

geo fix 30 28

You should het something like this in the simulator:

I hope this tutorial was helpful for you.

Thanks

akm

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