Delegate back button to child fragments.

gistfile1.java

public interface OnBackPressed {
    boolean onBackPressed();
}

// ----------------------------------------------------------

public class DelegateBackPressActivity extends Acitivity {
    @Override
    public void onBackPressed() {
        for (Fragment f : getFragmentManager().getFragments()) {
            if (f instanceof OnBackPressed && ((OnBackPressed) f).onBackPressed()) {
                return;
            }
        }
        super.onBackPressed();
    }
}