HttpGetXmlActivity.java

/*
 * Copyright 2010-2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.android.showcase.rest;

import java.util.ArrayList;
import java.util.List;

import org.springframework.android.showcase.AbstractAsyncListActivity;
import org.springframework.android.showcase.R;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.http.converter.xml.SimpleXmlHttpMessageConverter;
import org.springframework.web.client.RestTemplate;

import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;

/**
 * @author Roy Clarkson
 * @author Helena Edelson
 * @author Pierre-Yves Ricau
 */
public class HttpGetXmlActivity extends AbstractAsyncListActivity {

	protected static final String TAG = HttpGetXmlActivity.class.getSimpleName();

	// ***************************************
	// Activity methods
	// ***************************************
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
	}

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

		// when this activity starts, initiate an asynchronous HTTP GET request
		new DownloadStatesTask().execute();
	}

	// ***************************************
	// Private methods
	// ***************************************
	private void refreshStates(List<State> states) {
		if (states == null) {
			return;
		}

		StatesListAdapter adapter = new StatesListAdapter(this, states);
		setListAdapter(adapter);
	}

	// ***************************************
	// Private classes
	// ***************************************
	private class DownloadStatesTask extends AsyncTask<Void, Void, List<State>> {

		@Override
		protected void onPreExecute() {
			showLoadingProgressDialog();
		}

		@Override
		protected List<State> doInBackground(Void... params) {
			try {
				// The URL for making the GET request
				final String url = getString(R.string.base_uri) + "/states";

				// Set the Accept header for "application/xml"
				HttpHeaders requestHeaders = new HttpHeaders();
				List<MediaType> acceptableMediaTypes = new ArrayList<MediaType>();
				acceptableMediaTypes.add(MediaType.APPLICATION_XML);
				requestHeaders.setAccept(acceptableMediaTypes);

				// Populate the headers in an HttpEntity object to use for the request
				HttpEntity<?> requestEntity = new HttpEntity<Object>(requestHeaders);

				// Create a new RestTemplate instance
				RestTemplate restTemplate = new RestTemplate();
				restTemplate.getMessageConverters().add(new SimpleXmlHttpMessageConverter());

				// Perform the HTTP GET request
				ResponseEntity<StateList> responseEntity = restTemplate.exchange(url, HttpMethod.GET, requestEntity,
						StateList.class);

				// Return the list of states
				StateList stateList = responseEntity.getBody();

				return stateList.getStates();
			} catch (Exception e) {
				Log.e(TAG, e.getMessage(), e);
			}

			return null;
		}

		@Override
		protected void onPostExecute(List<State> result) {
			dismissProgressDialog();
			refreshStates(result);
		}

	}

}