edu.mit.mobile.android.json.JSONArrayAdapter.java Source code

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Here is the source code for edu.mit.mobile.android.json.JSONArrayAdapter.java

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package edu.mit.mobile.android.json;
/*
 * Copyright (C) 2011  MIT Mobile Experience Lab
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

import java.io.IOException;
import java.net.URI;

import org.apache.http.client.HttpClient;
import org.apache.http.client.HttpResponseException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;

import android.content.Context;
import android.os.AsyncTask;
import android.widget.BaseAdapter;

/**
 * An adapter for either a static JSONArray or a remote list that is loaded from a network.
 * If you need to do custom network requests, override getHttpClient() and getHttpGet().
 * You don't need to call them. 
 * 
 * @author steve
 *
 */
public abstract class JSONArrayAdapter extends BaseAdapter {

    private JSONArray ar;
    private LoadJSONArrayTask loadTask;

    public JSONArrayAdapter(Context context, JSONArray jsonArray) {
        ar = jsonArray;
    }

    public JSONArrayAdapter(Context context, URI remoteList) {
        ar = new JSONArray(); // temporary until we get our content...
        loadTask = new LoadJSONArrayTask();
        loadTask.execute(remoteList);
    }

    public int getCount() {
        return ar.length();
    }

    public void setJSONArray(JSONArray jsonArray) {
        ar = jsonArray;
        notifyDataSetChanged();
    }

    public Object getItem(int position) {
        try {
            return ar.get(position);
        } catch (final JSONException e) {

            e.printStackTrace();
            return null;
        }
    }

    public long getItemId(int position) {

        return position;
    }

    public HttpClient getHttpClient() {
        return new DefaultHttpClient();
    }

    public HttpGet getHttpGet(URI uri) {
        return new HttpGet(uri);
    }

    public void onPreExecute() {

    }

    public void onPostExecute(JSONArray result) {

    }

    private class LoadJSONArrayTask extends AsyncTask<URI, Double, JSONArray> {

        @Override
        protected void onPreExecute() {
            JSONArrayAdapter.this.onPreExecute();
        }

        @Override
        protected JSONArray doInBackground(URI... params) {
            JSONArray result = null;
            final HttpClient hc = getHttpClient();
            final HttpGet req = getHttpGet(params[0]);
            try {
                result = new JSONArray(hc.execute(req, new BasicResponseHandler()));
            } catch (final HttpResponseException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (final IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (final JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            return result;
        }

        @Override
        protected void onPostExecute(JSONArray result) {
            JSONArrayAdapter.this.onPostExecute(result);

            if (result == null) {
                return;
            }
            setJSONArray(result);
        }
    }
}