How to send a data to a web server from Android

The Android API has a set of functions that allows you to use HTTP requests, POST, GET etc. In this example i will provide a set of code that will allow you to update the contents of a file in a server using POST requests.

Our server side code will be very simple and it will be written in PHP. The code will get data from a post request, update a file with the data and load this file to display it in a browser.

Create PHP page on server "mypage.php", the code for php page is:-

 <?php

 $filename="datatest.html";
 file_put_contents($filename,$_POST["fname"]."<br />",FILE_APPEND);
 file_put_contents($filename,$_POST["fphone"]."<br />",FILE_APPEND);
 file_put_contents($filename,$_POST["femail"]."<br />",FILE_APPEND);
 file_put_contents($filename,$_POST["fcomment"]."<br />",FILE_APPEND);
 $msg=file_get_contents($filename);
 echo $msg; ?>

Create Android Project and write below code in HTTPExample.java

           HttpClient httpclient = new DefaultHttpClient();
       HttpPost httppost = new HttpPost("http://example.com/mypage.php");
         try {
       List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(4);

       nameValuePairs.add(new BasicNameValuePair("fname", "vinod"));
       nameValuePairs.add(new BasicNameValuePair("fphone", "1234567890"));
       nameValuePairs.add(new BasicNameValuePair("femail", "[email protected]"));
       nameValuePairs.add(new BasicNameValuePair("fcomment", "Help"));
       httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
       httpclient.execute(httppost);

     } catch (ClientProtocolException e) {
         // TODO Auto-generated catch block
     } catch (IOException e) {
         // TODO Auto-generated catch block
     }

Add permission in AndroidManifest.xml

    <uses-permission android:name="android.permission.INTERNET"/>

You can make GET or POST requests using AndroidHttpClient:

1. Create an AndroidHttpClient to execute your requests.
2. Create either an HttpGet or HttpPost request.
3. Use setEntity and setHeader methods to populate the request.
4. Use one of the execute methods on your client with your request.

This answer seems like a fairly complete code sample.

A quick example for a HTTP POST request is given here:

try {
    // Construct data
    String data = URLEncoder.encode("key1", "UTF-8") + "=" + URLEncoder.encode("value1", "UTF-8");
    data += "&" + URLEncoder.encode("key2", "UTF-8") + "=" + URLEncoder.encode("value2", "UTF-8");

    // Send data
    URL url = new URL("http://hostname:80/cgi");
    URLConnection conn = url.openConnection();
    conn.setDoOutput(true);
    OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
    wr.write(data);
    wr.flush();

    // Get the response
    BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
    String line;
    while ((line = rd.readLine()) != null) {
        // Process line...
    }
    wr.close();
    rd.close();
} catch (Exception e) {
}