publicclassHeadlinesFragmentextendsListFragment{ OnHeadlineSelectedListener mCallback; // Container Activity must implement this interface publicinterfaceOnHeadlineSelectedListener{ publicvoidonArticleSelected(int position); } @Override publicvoidonAttach(Activity activity){ super.onAttach(activity); // This makes sure that the container activity has implemented // the callback interface. If not, it throws an exception try { mCallback = (OnHeadlineSelectedListener) activity; } catch (ClassCastException e) { thrownew ClassCastException(activity.toString() + " must implement OnHeadlineSelectedListener"); } } ... }
@Override public void onListItemClick(ListView l, View v, intposition, longid) { // Send the event to the host activity mCallback.onArticleSelected(position); }
public static classMainActivityextendsActivity implements HeadlinesFragment.OnHeadlineSelectedListener{ ... public void onArticleSelected(int position) { // The user selected the headline of an article from the HeadlinesFragment // Do something here to display that article } }
public static class MainActivity extends Activity implements HeadlinesFragment.OnHeadlineSelectedListener{ ... public void onArticleSelected(intposition) { // The user selected the headline of an article from the HeadlinesFragment // Do something here to display that article ArticleFragment articleFrag = (ArticleFragment) getSupportFragmentManager().findFragmentById(R.id.article_fragment); if (articleFrag != null) { // If article frag is available, we're in two-pane layout... // Call a method in the ArticleFragment to update its content articleFrag.updateArticleView(position); } else { // Otherwise, we're in the one-pane layout and must swap frags... // Create fragment and give it an argument for the selected article ArticleFragment newFragment = newArticleFragment(); Bundle args = newBundle(); args.putInt(ArticleFragment.ARG_POSITION, position); newFragment.setArguments(args); FragmentTransaction transaction = getSupportFragmentManager().beginTransaction(); // Replace whatever is in the fragment_container view with this fragment, // and add the transaction to the back stack so the user can navigate back transaction.replace(R.id.fragment_container, newFragment); transaction.addToBackStack(null); // Commit the transaction transaction.commit(); } } }