Android JSON Parsing From URL



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"
    }
]

DOWNLOAD CODE

Output:

Android JSON Parsing From URL
Android JSON Parsing From URL