ArticleListFragment.java

package org.francho.apps.unutopia_android;

import org.francho.apps.unutopia_android.data.FeedContract.Articles;
import org.francho.apps.unutopia_android.widget.FeedsAdapter;

import android.app.Activity;
import android.content.Context;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.view.View;
import android.widget.ListView;

public class ArticleListFragment extends ListFragment {
	private static final String STATE_ACTIVATED_POSITION = "activated_position";

	public ArticleListFragment() {
		
	}
	
	
	private int mActivatedPosition = ListView.INVALID_POSITION;
	private ArticlesListener mArticlesListener = null;

	/**
	 * A callback interface that all activities containing this fragment must
	 * implement. This mechanism allows activities to be notified of item
	 * selections.
	 */
	public interface ArticlesListener {
		/**
		 * Callback for when an item has been selected.
		 */
		public void onArticleSelected(String articleUrl);
	}
	
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		final Context context = getActivity();
		setListAdapter(new FeedsAdapter(context ));
	}
	
	@Override
	public void onViewCreated(View view, Bundle savedInstanceState) {
		super.onViewCreated(view, savedInstanceState);

		// Restore the previously serialized activated item position.
		if (savedInstanceState != null
				&& savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
			setActivatedPosition(savedInstanceState
					.getInt(STATE_ACTIVATED_POSITION));
		}
	}
	
	@Override
	public void onAttach(Activity activity) {
		super.onAttach(activity);

		// Activities containing this fragment must implement its callbacks.
		if (!(activity instanceof ArticlesListener)) {
			throw new IllegalStateException(
					"Activity must implement ArticlesListener.");
		}

		mArticlesListener  = (ArticlesListener) activity;
	}

	@Override
	public void onDetach() {
		super.onDetach();

		mArticlesListener = null;
	}

	@Override
	public void onListItemClick(ListView listView, View view, int position,
			long id) {
		super.onListItemClick(listView, view, position, id);

		String[] projection = new String[]{Articles.LINK};
		Cursor cursor = getActivity().getContentResolver().query(Articles.getUri(id), projection , null, null, null);
		
		String link = null;
		if(cursor.moveToFirst()) {
			link = cursor.getString(0);
		}
		cursor.close();
		
		if(mArticlesListener != null) {
			mArticlesListener.onArticleSelected(link);
		}
	}

	@Override
	public void onSaveInstanceState(Bundle outState) {
		super.onSaveInstanceState(outState);
		if (mActivatedPosition != ListView.INVALID_POSITION) {
			// Serialize and persist the activated item position.
			outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition);
		}
	}

	/**
	 * Turns on activate-on-click mode. When this mode is on, list items will be
	 * given the 'activated' state when touched.
	 */
	public void setActivateOnItemClick(boolean activateOnItemClick) {
		// When setting CHOICE_MODE_SINGLE, ListView will automatically
		// give items the 'activated' state when touched.
		getListView().setChoiceMode(
				activateOnItemClick ? ListView.CHOICE_MODE_SINGLE
						: ListView.CHOICE_MODE_NONE);
	}

	private void setActivatedPosition(int position) {
		if (position == ListView.INVALID_POSITION) {
			getListView().setItemChecked(mActivatedPosition, false);
		} else {
			getListView().setItemChecked(position, true);
		}

		mActivatedPosition = position;
	}
}