So lets say u have Activity AB that controls Frag A and Fragment B.
MY ANSWER:
If the variable is used by Frag A and Frag B, put it in Activity AB. Then pass it to Frag A or Frag B everything they need it. Or have Frag A or Frag B retrieve it from Activity AB.
If the variable is used by Frag A only or Frag B only, put it in Frag A or Frag B respectively.
For methods that are used by both Frag A and Frag B, put those methods in another class and create instances of that class inside Frag A and Frag B for each of the 2 fragments to use.
The following is an answer I gave to another person. However, it seems relevant to your question so I am re-posting it here.
Inside Fragment A u need an interface that Activity AB can implement.
In the sample android code, they have:
private Callbacks mCallbacks = sDummyCallbacks;
/*A callback interface that all activities containing this fragment must implement. This mechanism allows activities to be notified of item selections.
*/
public interface Callbacks {
/*Callback for when an item has been selected. */
public void onItemSelected(String id);
}
/*A dummy implementation of the {@link Callbacks} interface that does nothing. Used only when this fragment is not attached to an activity. */
private static Callbacks sDummyCallbacks = new Callbacks() {
@Override
public void onItemSelected(String id) {
}
};
The Callback interface is put inside one of your Fragments (let’s say Fragment A). I think the purpose of this Callbacks interface is like a nested class inside Frag A which any Activity can implement. So if Fragment A was a TV, the CallBacks is the TV Remote (interface) that allows Fragment A to be used by Activity AB. I may be wrong about the details because I'm a noob but I did get my program to work perfectly on all screen sizes and this is what I used.
So inside Fragment A, we have:
(I took this from Android’s Sample programs)
@Override
public void onListItemClick(ListView listView, View view, int position, long id) {
super.onListItemClick(listView, view, position, id);
// Notify the active callbacks interface (the activity, if the
// fragment is attached to one) that an item has been selected.
mCallbacks.onItemSelected(DummyContent.ITEMS.get(position).id);
//mCallbacks.onItemSelected( PUT YOUR SHIT HERE. int, String, etc.);
//mCallbacks.onItemSelected (Object);
}
And inside Activity AB we override the onItemSelected method:
public class AB extends FragmentActivity implements ItemListFragment.Callbacks {
//...
@Override
//public void onItemSelected (CATCH YOUR SHIT HERE) {
//public void onItemSelected (Object obj) {
public void onItemSelected(String id) {
//Pass Data to Fragment B. For example:
Bundle arguments = new Bundle();
arguments.putString(“FragmentB_package”, id);
FragmentB fragment = new FragmentB();
fragment.setArguments(arguments);
getSupportFragmentManager().beginTransaction().replace(R.id.item_detail_container, fragment).commit();
}
So inside Activity AB, you basically throwing everything into a Bundle and passing it to B. If u are not sure how to use a Bundle, look the class up.
I am basically going by the sample code that Android provided. The one with the DummyContent stuff. When u make a new Android Application Package, it's the one titled MasterDetailFlow.
