Android - Passing value from ListFragment to another ListFragment

Question

I have a listview containing Category of items. When I press a category title on the list, it will display another listview containing items inside the chosen Category.

Answer 1

You should use Interface, it's the "official" way to pass values to Fragment. Take a look at this documentation here :

http://developer.android.com/guide/components/fragments.html#CommunicatingWithActivity

So what you need to do :

FragmentA --> Activity --> FragmentB

An invisible TextView is definitely not the correct solution...

EDIT A more detailed solution :

You define an interface (in a separate file or in your FragmentA class) :

public interface MyFragmentListener {
    public void onFragmentItemSelected(String url);
}

in your FragmentA class :

MyFragmentListener myListener;

public void setMyFragmentListener(MyFragmentListener listener) {
    myListener = listener;
}

// here I used the onClick method but you can call the listener whereever you like.
public void onClick(View view) {
    if (myListener != null) {
        myListener.onFragmentItemSelected(url);
    }
} 

Declaration your FragmentB class :

public class FragmentB extends Fragment implements MyFragmentListener {


    public void onFragmentItemSelected(String url) {
        // do what you want to do
    }


}

in your Activity :

// you tell your fragmentA that his listener is the FragmentB. And because you implemented the listener in FragmentB, everything is allright;
fragmentA.setMyFragmentListener(fragmentB));