First to explain how projects are setup:
- Android Library project with two classes:
- UserActivity - uses static field in HolderClass
- HolderClass - this one has static field Data
- Android Application that references Library project, has only one class:
- StarterActivity - when app is started, in onCreate it sets static field Data to some value, and it starts UserActivity
Now, the problem is: sometimes I get java.lang.NullPointerException for that static field Data - as if I never initialized it (or value got deleted in meantime). It never happened on my test device, but I keep getting error reports from client devices. I can only guess how that happens - maybe user navigates away from app, then comes back and system recreates whole application context, but in that context HolderClass has empty static field Data?
My question:
Is initialization of that static field from Activity's onCreate wrong approach? Should I put data in ApplicationContext? Or do something else?
I am open for all suggestions.
P.S. If you have problem visualizing from description, here is how everything I've said would look in code:
// IN ANDROID APP PROJECT
public class StarterActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// just start activity in library
Intent myIntent = new Intent(this, AutolaunchActivity.class);
startActivityForResult(myIntent, 1);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// exit when activity from library exits
finish();
}
}
// IN LIBRARY PROJECT
public class HolderClass {
public static String Data;
}
public class UserActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// init layout
}
public void someButtonClicked() {
HolderClass.Data.trim();
}
}
