Android Networking - Using Apache HttpClient Library

Most network-connected Android apps use HTTP to send and receive data. Android contains the Apache's HttpClient Library to perform network operations. In this tutorial we will learn about how to use Apache HttpClient library to make simple HTTP connection in Android.

The followings are some of the useful packages of Apache HttpClient library:

org.apache.http.HttpResponse
org.apache.http.client.HttpClient
org.apache.http.client.methods.HttpGet
org.apache.http.impl.client.DefaultHttpClient

Below are the code snippets to make a simple HTTP connection using Apache HttpClient library.

1. First create HttpClient object.

HttpClient httpclient=new DefaultHttpClient();

2. To retrieve the information from the server use the HttpGet class constructor.

HttpGet request=new HttpGet(“http://www.androidaspect.com”);

3. Then pass the HttpGet object in method execute() of HttpClient class to retrieve HttpResponse object.

HttpResponse response = httpclient.execute(request);

4. Then read the response received.

BufferedReader rd = new BufferedReader
(new InputStreamReader(response.getEntity().getContent()));
String line = "";
while ((line = rd.readLine()) != null) {
Log.d(“output: ”,line);
}

Note: To perform the network operations you must add the permission "android.permission.INTERNET" to "AndroidManifest.xml" file.

Final Code

The following is the final code to make a simple HTTP connection using Apache HttpClient library.

Project Name : ApacheHttpClientExample
Package : com.sunil.apachehttpclient

Main Activity : ApacheHttpClientExample.java

Layout : main.xml

Build Target : Android 2.2

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.sunil.apachehttpclient"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="5"
        android:targetSdkVersion="8" />

    <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.sunil.apachehttpclient.ApacheHttpClientExample"
            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>

main.xml

ApacheHttpClientExample.java

package com.sunil.apachehttpclient;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.EditText;

public class ApacheHttpClientExample extends Activity {

    HttpClient httpclient;
    HttpGet request;
    HttpResponse response;
    EditText result;

    /* Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        result = (EditText) findViewById(R.id.etResult);

       // Try to connect using Apache HttpClient Library
        try{
            httpclient=new DefaultHttpClient();
            request=new HttpGet("http://www.androidaspect.com");
            response = httpclient.execute(request);
        }

        catch (Exception e){
            //Code to handle exception
        }

        // response code
        try{
      BufferedReader rd = new
      BufferedReader(new InputStreamReader(response.getEntity().getContent()));
            String line = "";
            while ((line = rd.readLine()) != null) {
                result.append(line);
            }
        }
        catch (Exception e){
            //Code to handle exception
        }
    }
}

Output