HttpGetParametersActivity.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.AbstractAsyncActivity;
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.json.MappingJackson2HttpMessageConverter;
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;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

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

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

	// ***************************************
	// Activity methods
	// ***************************************
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.http_get_parameters_activity_layout);

		// Initiate the request for JSON data when the JSON button is pushed
		final Button buttonJson = (Button) findViewById(R.id.button_json);
		buttonJson.setOnClickListener(new View.OnClickListener() {
			public void onClick(View v) {
				new DownloadStateTask().execute(MediaType.APPLICATION_JSON);
			}
		});

		// Initiate the request for XML data when the XML button is pushed
		final Button buttonXml = (Button) findViewById(R.id.button_xml);
		buttonXml.setOnClickListener(new View.OnClickListener() {
			public void onClick(View v) {
				new DownloadStateTask().execute(MediaType.APPLICATION_XML);
			}
		});
	}

	// ***************************************
	// Private methods
	// ***************************************
	private void showState(State state) {
		// display a notification to the user with the state
		if (state != null) {
			Toast.makeText(this, state.getFormattedName(), Toast.LENGTH_LONG).show();
		} else {
			Toast.makeText(this, "No state found with that abbreviation!", Toast.LENGTH_LONG).show();
		}
	}

	// ***************************************
	// Private classes
	// ***************************************
	private class DownloadStateTask extends AsyncTask<MediaType, Void, State> {

		private String abbreviation;

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

			// retrieve the abbreviation from the EditText field
			EditText editText = (EditText) findViewById(R.id.edit_text_abbreviation);

			abbreviation = editText.getText().toString();
		}

		@Override
		protected State doInBackground(MediaType... params) {
			try {
				if (params.length <= 0) {
					return null;
				}

				MediaType mediaType = params[0];

				// The URL for making the GET request
				final String url = getString(R.string.base_uri) + "/state/{abbreviation}";

				// Set the Accept header for "application/json" or "application/xml"
				HttpHeaders requestHeaders = new HttpHeaders();
				List<MediaType> acceptableMediaTypes = new ArrayList<MediaType>();
				acceptableMediaTypes.add(mediaType);
				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();
				if (mediaType.equals(MediaType.APPLICATION_JSON)) {
					restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
				} else if (mediaType.equals(MediaType.APPLICATION_XML)) {
					restTemplate.getMessageConverters().add(new SimpleXmlHttpMessageConverter());
				}

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

				// Return the state from the ResponseEntity
				return responseEntity.getBody();
			} catch (Exception e) {
				Log.e(TAG, e.getMessage(), e);
			}

			return null;
		}

		@Override
		protected void onPostExecute(State state) {
			dismissProgressDialog();
			showState(state);
		}

	}

}