1. Android and JSON
JSON is a very condense data exchange format. Android includes the json.org libraries which allow to work easily with JSON files.
Twitter is a great source for JSON. You can just call a URI and retrieve JSON. Here are some examples:
Table 1. Twitter URI's
URI | Description |
---|---|
http://twitter.com/statuses/user_timeline/vogella.json | Get the timeline of user vogella . |
http://search.twitter.com/search.json?q=android | Search for the term "android" on Twitter. |
http://twitter.com/statuses/user_timeline/vogella.json | Returns the user data of user vogella . |
Please note that some URI's return a JSONObject object while others return a JSONArray. The following coding uses an URI which returns an JSONArray.
Create a new Android project "de.vogella.android.twitter.json" with the package "de.vogella.android.twitter.json" and the activity "ParseJSON".
Create the following coding for the activity. This will download the twitter feed for the userhttp://twitter.com/vogella and write the number of entries and the text messages to the Android log file.
package de.vogella.android.twitter.json; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.StatusLine; import org.apache.http.client.ClientProtocolException; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.DefaultHttpClient; import org.json.JSONArray; import org.json.JSONObject; import android.app.Activity; import android.os.Bundle; import android.util.Log; public class ParseJSON extends Activity {
To run this example assign the uses-permission to your "AndroidManifest.xml" for "android.permission.INTERNET".
Writing JSON is very simple. Just create the JSONObject or JSONArray and use the toString() method.
public void writeJSON() { JSONObject object = new JSONObject(); try { object.put("name", "Jack Hack"); object.put("score", new Integer(200)); object.put("current", new Double(152.32)); object.put("nickname", "Hacker"); } catch (JSONException e) { e.printStackTrace(); } System.out.println(object); }