Is it possible to initialize object which is extend to class Activity
<p>I have main activity which call other object, for example GPS class. This GPS class extends Activiy class. </p>

<p>snapshot main activity:</p>

<pre><code>public class MemoPosition extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        GPS GPSnode = new GPS();
        if (!GPSnode.isGPSenabled()){
            createGpsDisabledAlert();
        }
    }
    private void createGpsDisabledAlert(){
    }
}
</code></pre>

<p>snapshot GPS class:</p>

<pre><code>public class GPS extends Activity{
    private Double latitude;
    private Double longitude;
    private LocationManager locationManager;

    public void GPS(){
        // Construction
        String context = Context.LOCATION_SERVICE;
        locationManager = (LocationManager)getSystemService(context);

        if (isGPSenabled()){
           // do something 
        }    
}
</code></pre>

<p>I've also put the GPS class to manifest as part of Activity apps.
Running the code, and fatal error Force close.
Logcat:</p>

<pre><code>12-24 22:51:32.270: ERROR/AndroidRuntime(5558): FATAL EXCEPTION: main
12-24 22:51:32.270: ERROR/AndroidRuntime(5558): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.dromdev.project.memoposition/com.dromdev.project.memoposition.MemoPosition}: java.lang.NullPointerException
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at android.os.Handler.dispatchMessage(Handler.java:99)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at android.os.Looper.loop(Looper.java:123)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at android.app.ActivityThread.main(ActivityThread.java:4627)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at java.lang.reflect.Method.invokeNative(Native Method)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at java.lang.reflect.Method.invoke(Method.java:521)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:876)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:634)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at dalvik.system.NativeStart.main(Native Method)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558): Caused by: java.lang.NullPointerException
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at com.dromdev.project.memoposition.GPS.isGPSenabled(GPS.java:48)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at com.dromdev.project.memoposition.MemoPosition.onCreate(MemoPosition.java:23)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
12-24 22:51:32.270: ERROR/AndroidRuntime(5558):     ... 11 more
</code></pre>

<p>I'm curious if class which inherit activity class couldn't be initialized as normal Activity. Should it be called by Intent ? I just need GPS class as object which responsible to GPS functionality, however it's required to extend Activity for some context. Please advice.</p>
