Activity switch and Async Android - android-layout

Question

I have 2 activities: MainActivity which is associated with main.xml layout (app "Home" screen) and AboutActivity which is associated with about.xml layout (app "About" screen).
While in AboutActivity, an Async task within MainActivity still tries to access main.xml. My app to stop working as a result.
Is there any way I can?
"pause" the Async task within MainActivity and "resume" them when
the user switches back from AboutActivity
or still access main.xml in the background while in AboutActivity
Additional information:
MainActivity is the launch activity. AboutActivity extends MainActivity. Users can go to "About" screen/ switch to AboutActivity using the option menu.
The Async task within MainActivity put the user's current location into a textview. about.xml only contains static text. AboutActivity does nothing but show about.xml.
AboutActivity:
public class AboutActivity extends MainActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.about);
}
}
MainActivity:
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Creating a new non-ui thread task to download Google place json data
PlacesTask placesTask = new PlacesTask();
// Invokes the "doInBackground()" method of the class PlaceTask
placesTask.execute(sb.toString());
}
/** A class, to download Google Places */
private class PlacesTask extends AsyncTask<String, Integer, String>{
String data = null;
// Invoked by execute() method of this object
#Override
protected String doInBackground(String... url) {
//make asynctask wait for debugger
//android.os.Debug.waitForDebugger();
try{
data = downloadUrl(url[0]);
}catch(Exception e){
Log.d(DEBUG,e.toString());
}
return data;
}
// Executed after the complete execution of doInBackground() method
#Override
protected void onPostExecute(String result){
TextView curLoc = (TextView) findViewById(R.id.CurrentLocation);
curLoc.setText(result);
}
}
}

Answer 1

AsyncTask not pause so we can store the data temporary when task complete and while start background activity than show data on textView.

Answer 2

I've solved the problem. It was a partly a variable scope problem and partly due the fact that I cannot use findViewById() there, it always return null
curLoc is null in onPostExecute in the AsyncTask.
I removed the following:
TextView curLoc = (TextView) findViewById(R.id.CurrentLocation);
and declared curLoc as a attribute of the class MainActivity
private TextView curLoc;
and also put in onCreate()
curLoc = (TextView) findViewById(R.id.CurrentLocation);