Question

I have a Fragment with a Button embedded inside of a FragmentActivity. When I click the button I want the Fragment to be replaced with another Fragment. The problem is: the Fragment is a inner static class of my Activity and the method is a non-static one. I solved this problem by making an instance of my Activity class, but when I click on the button inside the fragment the application crashes.

Here is the code:

public class Stdp extends SherlockFragmentActivity implements ActionBar.OnNavigationListener {

public static class Bottomfrag extends SherlockFragment {

    static Bottomfrag newInstance() {
        Bottomfrag f = new Bottomfrag();
        return f;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.bottom_choose, container, false);
        View li = v.findViewById(R.id.layoutbottom);
        li.setBackgroundColor(Color.parseColor("#FFBB33"));
        View button = v.findViewById(R.id.button1);
        button.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View arg0) {
                Stdp t = new Stdp();
                t.addFragmentToStack();
            }
        });
        return v;
    }
}


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_stdp);

    Context context = getSupportActionBar().getThemedContext();
    ArrayAdapter<CharSequence> list = ArrayAdapter.createFromResource(context, R.array.test_array, R.layout.sherlock_spinner_item);
    list.setDropDownViewResource(R.layout.sherlock_spinner_dropdown_item);

    getSupportActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
    getSupportActionBar().setListNavigationCallbacks(list, this);


    if (savedInstanceState == null) {
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        Fragment bottom = new Bottomfrag();
        ft.add(R.id.su1, bottom);
        ft.commit();
    }
}


@Override
public boolean onNavigationItemSelected(int itemPosition, long itemId) {
    // TODO Auto-generated method stub
    return false;
}

public void addFragmentToStack() {
Fragment newFragment = Bottomfrag.newInstance();
    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.replace(R.id.su1, newFragment);
    ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_CLOSE);
    ft.addToBackStack(null);
    ft.commit();
}
}

---

I found a solution for my problem. The only thing I had to do is to move the addFragmentToStack to the Bottomfrag class.

Answer 1

I solved this problem by making an instance of my Activity class.

Instantiating an Activity is almost never a solution when it comes to Android development… in fact, I can’t imagine a scenario in which you would ever want to create a new Activity using the default constructor.

You can reference the static instance of your Activity with ActivityName.this.

You should also move addFragmentToStack to the Bottomfrag class.