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POUnable to start activity implementing LocationListener for detecting location of android device using GPS
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copied!<p>I develop simple application that detects the location of android device and display its values in text Views</p> <p>The application crashes once it starts throwing RuntimeException.</p> <p>Following is GPS.java</p> <pre><code>public class GPS extends Activity implements LocationListener { private TextView latituteField; private TextView longitudeField; private LocationManager locationManager; private String provider; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.gps); latituteField = (TextView) findViewById(R.id.TextView02); longitudeField = (TextView) findViewById(R.id.TextView04); LocationManager service = (LocationManager) getSystemService(LOCATION_SERVICE); boolean enabled = service .isProviderEnabled(LocationManager.GPS_PROVIDER); if (!enabled) { Intent intent = new Intent( android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS); startActivity(intent); } Criteria criteria = new Criteria(); provider = locationManager.getBestProvider(criteria,false); Location location = locationManager.getLastKnownLocation(provider); if (location != null) { Log.d("PROVIDER", "Provider " + provider + " has been selected."); onLocationChanged(location); } else { latituteField.setText("Location not available"); longitudeField.setText("Location not available"); } } </code></pre> <p>Log is as following :</p> <blockquote> <p>10-09 16:49:35.733: E/AndroidRuntime(1616): FATAL EXCEPTION: main 10-09 16:49:35.733: E/AndroidRuntime(1616): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.gps/com.example.gps.GPS}: java.lang.NullPointerException 10-09 16:49:35.733: E/AndroidRuntime(1616): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956) 10-09 16:49:35.733: E/AndroidRuntime(1616): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981) 10-09 16:49:35.733: E/AndroidRuntime(1616): at android.app.ActivityThread.access$600(ActivityThread.java:123) 10-09 16:49:35.733: E/AndroidRuntime(1616): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147) 10-09 16:49:35.733: E/AndroidRuntime(1616): at android.os.Handler.dispatchMessage(Handler.java:99) 10-09 16:49:35.733: E/AndroidRuntime(1616): at android.os.Looper.loop(Looper.java:137) 10-09 16:49:35.733: E/AndroidRuntime(1616): at android.app.ActivityThread.main(ActivityThread.java:4424) 10-09 16:49:35.733: E/AndroidRuntime(1616): at java.lang.reflect.Method.invokeNative(Native Method) 10-09 16:49:35.733: E/AndroidRuntime(1616): at java.lang.reflect.Method.invoke(Method.java:511) 10-09 16:49:35.733: E/AndroidRuntime(1616): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 10-09 16:49:35.733: E/AndroidRuntime(1616): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 10-09 16:49:35.733: E/AndroidRuntime(1616): at dalvik.system.NativeStart.main(Native Method) 10-09 16:49:35.733: E/AndroidRuntime(1616): Caused by: java.lang.NullPointerException 10-09 16:49:35.733: E/AndroidRuntime(1616): at com.example.gps.GPS.onCreate(GPS.java:44) 10-09 16:49:35.733: E/AndroidRuntime(1616): at android.app.Activity.performCreate(Activity.java:4465) 10-09 16:49:35.733: E/AndroidRuntime(1616): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049) 10-09 16:49:35.733: E/AndroidRuntime(1616): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920) 10-09 16:49:35.733: E/AndroidRuntime(1616): ... 11 more</p> </blockquote>

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