What is a simple way to implement a websocket client in Android? Is the following example correct?

Question

I was trying to use a class that implements a WebSocket client in Android. But I get the following error:

12-07 11:22:46.286 31579-31579/com.domain.wsocketchat W/System: ClassLoader referenced unknown path: /data/app/com.domain.wsocketchat-2/lib/arm 12-07 11:22:46.392 31579-31579/com.domain.wsocketchat W/System.err: an error occurred:java.net.SocketException: socket failed: EACCES (Permission denied) 

The class that I'm using follows:

import org.java_websocket.client.WebSocketClient; import org.java_websocket.drafts.Draft; import org.java_websocket.drafts.Draft_10; import org.java_websocket.handshake.ServerHandshake;  import java.net.URI;  public class EmptyClient extends WebSocketClient {     public EmptyClient(URI serverUri, Draft draft) {         super(serverUri, draft);     }      public EmptyClient(URI serverURI) {         super(serverURI);     }      @Override     public void onOpen(ServerHandshake handshakedata) {         System.out.println("new connection opened");     }      @Override     public void onClose(int code, String reason, boolean remote) {         System.out.println("closed with exit code " + code + " additional info: " + reason);     }      @Override     public void onMessage(String message) {         System.out.println("received message: " + message);     }      @Override     public void onError(Exception ex) {         System.err.println("an error occurred:" + ex);     } } 

The class is called within the onCreate():

WebSocketClient client = null; try {     client = new EmptyClient(new URI("ws://192.168.1.135:9000/server.php"), new Draft_10()); } catch (URISyntaxException e) {     e.printStackTrace(); } client.connect(); 

AndroidManifest:

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

Sdk: minSdkVersion 16

Anyone have any idea, what could be the problem? It seems everything allright! Thank you in advance.

Answer 1

I already resolved the problem by using another class, that handles the websocket client:

    import android.app.Activity;     import android.app.Fragment;     import android.os.Build;     import android.os.Bundle;     import android.util.Log;     import android.view.LayoutInflater;     import android.view.Menu;     import android.view.MenuItem;     import android.view.View;     import android.view.ViewGroup;     import android.widget.EditText;     import android.widget.TextView;      import org.java_websocket.client.WebSocketClient;     import org.java_websocket.handshake.ServerHandshake;      import java.net.URI;     import java.net.URISyntaxException;      public class MainActivity extends Activity {         private WebSocketClient mWebSocketClient;          @Override         protected void onCreate(Bundle savedInstanceState) {             super.onCreate(savedInstanceState);             setContentView(R.layout.activity_main);              connectWebSocket();              if (savedInstanceState == null) {                 getFragmentManager().beginTransaction()                         .add(R.id.container, new PlaceholderFragment())                         .commit();             }         }           @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;         }          @Override         public boolean onOptionsItemSelected(MenuItem item) {             // Handle action bar item clicks here. The action bar will             // automatically handle clicks on the Home/Up button, so long             // as you specify a parent activity in AndroidManifest.xml.             switch (item.getItemId()) {                 case R.id.action_settings:                     return true;             }             return super.onOptionsItemSelected(item);         }          /**          * A placeholder fragment containing a simple view.          */         public static class PlaceholderFragment extends Fragment {              public PlaceholderFragment() {             }              @Override             public View onCreateView(LayoutInflater inflater, ViewGroup container,                     Bundle savedInstanceState) {                 View rootView = inflater.inflate(R.layout.fragment_main, container, false);                 return rootView;             }         }          private void connectWebSocket() {             URI uri;             try {                 uri = new URI("ws://192.168.1.135:9000/");             } catch (URISyntaxException e) {                 e.printStackTrace();                 return;             }              mWebSocketClient = new WebSocketClient(uri) {                 @Override                 public void onOpen(ServerHandshake serverHandshake) {                     Log.i("Websocket", "Opened");                     mWebSocketClient.send("Hello from " + Build.MANUFACTURER + " " + Build.MODEL);                 }                  @Override                 public void onMessage(String s) {                     final String message = s;                     runOnUiThread(new Runnable() {                         @Override                         public void run() {                             TextView textView = (TextView)findViewById(R.id.messages);                             textView.setText(textView.getText() + "\n" + message);                         }                     });                 }                  @Override                 public void onClose(int i, String s, boolean b) {                     Log.i("Websocket", "Closed " + s);                 }                  @Override                 public void onError(Exception e) {                     Log.i("Websocket", "Error " + e.getMessage());                 }             };             mWebSocketClient.connect();         }          public void sendMessage(View view) {             EditText editText = (EditText)findViewById(R.id.message);             mWebSocketClient.send(editText.getText().toString());             editText.setText("");         }     } 

For anyone that is interested, I've used a Websocket-ChatServer written in PHP:

<?php $r = $_SERVER['SERVER_ADDR']; if($r=="::1") $r="localhost";  $host = $r; //'localhost'; //host $port = '9000'; //port $null = NULL; //null var  //Create TCP/IP sream socket $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP); //reuseable port socket_set_option($socket, SOL_SOCKET, SO_REUSEADDR, 1);  //bind socket to specified host socket_bind($socket, 0, $port);  //listen to port socket_listen($socket);  //create & add listning socket to the list $clients = array($socket);  //start endless loop, so that our script doesn't stop while (true) {     //manage multipal connections     $changed = $clients;     //returns the socket resources in $changed array     socket_select($changed, $null, $null, 0, 10);      //check for new socket     if (in_array($socket, $changed)) {         $socket_new = socket_accept($socket); //accpet new socket         $clients[] = $socket_new; //add socket to client array          $header = socket_read($socket_new, 1024); //read data sent by the socket         perform_handshaking($header, $socket_new, $host, $port); //perform websocket handshake          socket_getpeername($socket_new, $ip); //get ip address of connected socket         $response = mask(json_encode(array('type'=>'system', 'message'=>$ip.' connected'))); //prepare json data         send_message($response); //notify all users about new connection          //make room for new socket         $found_socket = array_search($socket, $changed);         unset($changed[$found_socket]);     }      //loop through all connected sockets     foreach ($changed as $changed_socket) {           //check for any incomming data         while(socket_recv($changed_socket, $buf, 1024, 0) >= 1)         {             $received_text = unmask($buf); //unmask data             $tst_msg = json_decode($received_text); //json decode              $user_name = $tst_msg->name; //sender name             $user_message = $tst_msg->message; //message text             $user_color = $tst_msg->color; //color              //prepare data to be sent to client             $response_text = mask(json_encode(array('type'=>'usermsg', 'name'=>$user_name, 'message'=>$user_message, 'color'=>$user_color)));             send_message($response_text); //send data             break 2; //exist this loop         }          $buf = @socket_read($changed_socket, 1024, PHP_NORMAL_READ);         if ($buf === false) { // check disconnected client             // remove client for $clients array             $found_socket = array_search($changed_socket, $clients);             socket_getpeername($changed_socket, $ip);             unset($clients[$found_socket]);              //notify all users about disconnected connection             $response = mask(json_encode(array('type'=>'system', 'message'=>$ip.' disconnected')));             send_message($response);         }     } } // close the listening socket socket_close($sock);  function send_message($msg) {     global $clients;     foreach($clients as $changed_socket)     {         @socket_write($changed_socket,$msg,strlen($msg));     }     return true; }   //Unmask incoming framed message function unmask($text) {     $length = ord($text[1]) & 127;     if($length == 126) {         $masks = substr($text, 4, 4);         $data = substr($text, 8);     }     elseif($length == 127) {         $masks = substr($text, 10, 4);         $data = substr($text, 14);     }     else {         $masks = substr($text, 2, 4);         $data = substr($text, 6);     }     $text = "";     for ($i = 0; $i < strlen($data); ++$i) {         $text .= $data[$i] ^ $masks[$i%4];     }     return $text; }  //Encode message for transfer to client. function mask($text) {     $b1 = 0x80 | (0x1 & 0x0f);     $length = strlen($text);      if($length <= 125)         $header = pack('CC', $b1, $length);     elseif($length > 125 && $length < 65536)         $header = pack('CCn', $b1, 126, $length);     elseif($length >= 65536)         $header = pack('CCNN', $b1, 127, $length);     return $header.$text; }  //handshake new client. function perform_handshaking($receved_header,$client_conn, $host, $port) {     $headers = array();     $lines = preg_split("/\r\n/", $receved_header);     foreach($lines as $line)     {         $line = chop($line);         if(preg_match('/\A(\S+): (.*)\z/', $line, $matches))         {             $headers[$matches[1]] = $matches[2];         }     }      $secKey = $headers['Sec-WebSocket-Key'];     $secAccept = base64_encode(pack('H*', sha1($secKey . '258EAFA5-E914-47DA-95CA-C5AB0DC85B11')));     //hand shaking header     $upgrade  = "HTTP/1.1 101 Web Socket Protocol Handshake\r\n" .     "Upgrade: websocket\r\n" .     "Connection: Upgrade\r\n" .     "WebSocket-Origin: $host\r\n" .     "WebSocket-Location: ws://$host:$port/demo/shout.php\r\n".     "Sec-WebSocket-Accept:$secAccept\r\n\r\n";     socket_write($client_conn,$upgrade,strlen($upgrade)); } 

In order to start the websocket server it's needed to run a console command like this: php -q myserver.php