JSON is one of the best method to provide data in android from web application. So I am discussing here how to parse a JSON response from a URL and use it, in this tutorial Android JSON Parsing From URL. JSON data has square and curly brackets which denotes JSON array and JSON object simultaneously.
Creating Project:
Create a new project in Eclipse IDE as “Read JSON from URL” with package com.tricks.readjsonfromurl. Now Create the main Activity as “MainActivity” and the main Layout as activity_main.
Manifest:
Just add a permission “android.permission.INTERNET” to the manifest file for access external url or address.
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.tricks.readjsonfromurl" android:versionCode="1" android:versionName="1.0" >
<uses-sdk android:minSdkVersion="9" android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.INTERNET"/>
<application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" >
<activity android:name="com.tricks.readjsonfromurl.MainActivity" android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Creating Layout:
The main layout for our project is “activity_main” which has three TextView as Label and other three for display the website ID, Name and URL of JSON object from the URL.
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" >
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:textStyle="bold" android:textSize="18sp" android:text="@string/info" />
<TextView android:id="@+id/wid" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="75dp" android:layout_marginTop="45dp" />
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="45dp" android:textStyle="bold" android:text="@string/wid" />
<TextView android:id="@+id/name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/wid" android:layout_marginLeft="75dp" android:layout_marginTop="30dp" />
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/wid" android:layout_marginTop="30dp" android:text="@string/name" android:textStyle="bold" />
<TextView android:id="@+id/url" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/name" android:layout_marginLeft="75dp" android:layout_marginTop="30dp" />
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/name" android:layout_marginTop="30dp" android:textStyle="bold" android:text="@string/url" />
</RelativeLayout>
Creating String Values:
You should create string constants values in re/values/strings.xml to use in layout.
strings.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">Read Json From URL</string>
<string name="action_settings">Settings</string>
<string name="hello_world">Hello world!</string>
<string name="info">Website Information from URL</string>
<string name="wid">ID</string>
<string name="name">Name</string>
<string name="url">Website</string>
</resources>
Creating Activity:
Now to get JSON data from the URL we need to create a HttpClient and get the data from URL “http://demos.tricksofit.com/files/json.php”. If you have only JSON object you can use JSONObject json = new JSONObject(str);, If you have JSON Array then you can use JSONArray jArray = new JSONArray(str);. In MainActivity we will get the ID, Name and URL of the first object and displaying it on the layout.
MainActivity.java
package com.tricks.readjsonfromurl;
import java.io.IOException;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.os.Bundle;
import android.os.StrictMode;
import android.app.Activity;
import android.view.Menu;
import android.widget.TextView;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
.detectAll()
.penaltyLog()
.penaltyDialog()
.build());
StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder().detectAll()
.penaltyLog()
.build());
TextView wid = (TextView) findViewById(R.id.wid);
TextView name = (TextView) findViewById(R.id.name);
TextView url = (TextView) findViewById(R.id.url);
JSONObject json = null;
String str = "";
HttpResponse response;
HttpClient myClient = new DefaultHttpClient();
HttpPost myConnection = new HttpPost("http://demos.tricksofit.com/files/json.php");
try {
response = myClient.execute(myConnection);
str = EntityUtils.toString(response.getEntity(), "UTF-8");
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try{
JSONArray jArray = new JSONArray(str);
json = jArray.getJSONObject(0);
wid.setText(json.getString("id"));
name.setText(json.getString("name"));
url.setText(json.getString("url"));
} catch ( JSONException e) {
e.printStackTrace();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
JSON Data :
[
{
"id": "01",
"name": "Tricks Of IT",
"url": "www.tricksofit.com"
},
{
"id": "02",
"name": "Demos Tricks Of IT",
"url": "www.demos.tricksofit.com"
}
]
Output:
