SocialFragment.java

package com.vt.vthacks;

import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import com.vt.vthacks.model.IPhotoStreamItem;
import com.vt.vthacks.model.impl.TwitterPhotoStreamItem;
import com.vt.vthacks.view.PhotoStreamAdapter;
import com.vt.vthacks.view.PhotoStreamAdapter.OnImageClickListener;
import com.vt.vthacks.view.PullToRefreshListView;
import com.vt.vthacks.view.PullToRefreshListView.OnRefreshListener;
import com.vt.vthacks.view.PullToRefreshListView.OnScrollToBottomListener;

import twitter4j.Query;
import twitter4j.QueryResult;
import twitter4j.Twitter;
import twitter4j.TwitterException;
import twitter4j.TwitterFactory;
import twitter4j.conf.ConfigurationBuilder;
import android.graphics.Bitmap;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.ImageView;

// -------------------------------------------------------------------------
/**
 * This class handles the interaction/data for the Social page
 *
 * @author Brandon Potts
 * @version Mar 10, 2014
 */
public class SocialFragment extends Fragment {

	private static final String TAG = "SocialActivity";
	private static final String QUERY = "filter:images +exclude:retweets #vthacks";

	private PullToRefreshListView listView;
	private PhotoStreamAdapter adapter;
	private Twitter twitter;
	private View previewHolder;
	private ImageView imageView;
	private QueryResult lastResult;

	// ----------------------------------------------------------
	/**
	 * Sets up the Social page
	 *
	 * @param savedInstanceState
	 *            is data that was most recently supplied
	 */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		ConfigurationBuilder cb = new ConfigurationBuilder();
		TwitterFactory tf = new TwitterFactory(cb.build());
		twitter = tf.getInstance();
	}

	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		View view = inflater.inflate(R.layout.social, container, false);

		listView = (PullToRefreshListView) view.findViewById(R.id.listView);
		listView.setOnRefreshListener(new OnRefreshListener() {

			@Override
			public void onRefresh() {
				resetList();
				new TwitterTask().execute();
			}
		});

		previewHolder = view.findViewById(R.id.previewBox);
		imageView = (ImageView) view.findViewById(R.id.fullImageView);

		adapter = new PhotoStreamAdapter(getActivity(), new ArrayList<IPhotoStreamItem>(),
				new OnImageClickListener() {

			@Override
			public void onImageClicked(Bitmap bitmap) {
				imageView.setImageBitmap(bitmap);
				previewHolder.setVisibility(View.VISIBLE);
				imageView.setOnClickListener(new OnClickListener() {
					@Override
					public void onClick(View v) {
						previewHolder.setVisibility(View.GONE);
					}
				});
			}
		});
		listView.setAdapter(adapter);

		listView.onRefresh();

		return view;
	}

	@Override
	public void onStop() {
		super.onStop();
		TwitterPhotoStreamItem.clearCache();
		System.gc();
	}

	private void resetList() {
		lastResult = null;
		listView.setOnScrollToBottomListener(null);
		adapter.clear();
		adapter.notifyDataSetChanged();
	}

	private class TwitterTask extends AsyncTask<Void, Void, List<IPhotoStreamItem>> {

		@Override
		protected List<IPhotoStreamItem> doInBackground(Void... arg0) {
			Query query = null;
			if (lastResult == null) {
				query = new Query(QUERY);
			}
			else {
				if (!lastResult.hasNext()) {
					return null;
				}
				query = lastResult.nextQuery();
			}

			List<IPhotoStreamItem> photoStream = new ArrayList<IPhotoStreamItem>();
			try {
				lastResult = twitter.search(query);
			}
			catch (TwitterException e) {
				Log.d(TAG, "Problem searching for tweets.");
				return photoStream;
			}

			if (lastResult != null) {
				List<twitter4j.Status> statuses = lastResult.getTweets();
				if (statuses != null) {
					for (twitter4j.Status status : statuses) {
						photoStream.add(new TwitterPhotoStreamItem(status));
					}
				}
			}

			return photoStream;
		}

		@Override
		protected void onPostExecute(List<IPhotoStreamItem> photoStream) {
			super.onPostExecute(photoStream);

			if (photoStream != null) {
				adapter.addAll(photoStream);
				adapter.notifyDataSetChanged();

				Date date = new Date(System.currentTimeMillis());

				String message = "Last updated at " + DateFormat.getDateTimeInstance().format(date);
				listView.onRefreshComplete(message);
				listView.onScrollToBottomComplete(message);

				listView.setOnScrollToBottomListener(new OnScrollToBottomListener() {

					@Override
					public void onScrollToBottom() {
						new TwitterTask().execute();
					}
				});
			}
		}
	}
}