Android WebSocket Client With Kotlin

by androidexample

Android WebSocket Client With Kotlin.

Web Socket Clinet Side For Android With Kotlin you can use this app with Ktor Server Side, Find Ktor Project Here: Ktor WebSocket Server Side

App Preview

Usage

add this line into your build.gradle app.

dependencies {
    implementation 'org.java-websocket:Java-WebSocket:1.4.0'
}

Add This Code In MainActivity

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.*
import androidx.appcompat.app.AppCompatActivity
import com.encept.websocket_client.databinding.ActivityMainBinding
import java.net.URI
import java.util.*


class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding
    private lateinit var webSocketClient: ChatWebSocketClient
    private var AL: ArrayList<HashMap<String, Any>> = ArrayList()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        val btnSend = binding.btnSend
        val editMsg = binding.editMsg
        val listview1 = binding.listview1

        // load server url from strings.xml
        val serverUri = URI(getString(R.string.server_url))

        webSocketClient = ChatWebSocketClient(serverUri) { message ->
            // display incoming message in ListView
            runOnUiThread {
                run {
                    val _item = HashMap<String, Any>()
                    _item["message"] = message
                    AL.add(_item)
                }
                listview1.adapter = Listview1Adapter(AL)
            }
        }
        // connect to websocket server
        webSocketClient.connect()


        btnSend.setOnClickListener {
            try {
                // send message to websocket server
                webSocketClient.sendMessage(editMsg.text.toString())
                editMsg.setText("")
            } catch (e: Exception) {
                e.printStackTrace()
                Toast.makeText(this, e.toString(), Toast.LENGTH_SHORT).show()
            }
        }
    }

    override fun onDestroy() {
        super.onDestroy()
        // close websocket connection
        webSocketClient.close()
    }


    class Listview1Adapter(private val _data: ArrayList<HashMap<String, Any>>) : BaseAdapter() {
        override fun getCount(): Int {
            return _data.size
        }

        override fun getItem(_index: Int): HashMap<String, Any> {
            return _data[_index]
        }

        override fun getItemId(_index: Int): Long {
            return _index.toLong()
        }

        override fun getView(_position: Int, _v: View?, _container: ViewGroup?): View? {
            val _inflater = LayoutInflater.from(_container?.context)
            var _view = _v
            if (_view == null) {
                _view = _inflater.inflate(R.layout.cul, _container, false)
            }

            val text2 = _view?.findViewById<TextView>(R.id.text2)

            if (text2 != null) {
                text2.text = _data[_position]["message"].toString()
            }

            return _view
        }

    }

}

then, add this code at activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical">

  <LinearLayout
      android:id="@+id/linear2"
      android:layout_width="wrap_content"
      android:layout_height="0dp"
      android:layout_weight="1"
      android:orientation="vertical"
      android:padding="4dp">

      <ListView
          android:id="@+id/listview1"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:choiceMode="none"
          android:padding="8dp"/>
  </LinearLayout>

  <LinearLayout
      android:id="@+id/linear1"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:orientation="horizontal"
      android:padding="2dp">

      <EditText
          android:id="@+id/edit_msg"
          android:layout_width="0dp"
          android:layout_height="wrap_content"
          android:layout_weight="1"
          android:hint="@string/enter_message"
          android:importantForAutofill="no"
          android:padding="8dp"
          android:textColor="#000000"
          android:textColorHint="#607D8B"
          android:textSize="12sp"
          tools:ignore="TextFields" />

      <Button
          android:id="@+id/btnSend"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:padding="8dp"
          android:text="@string/send"
          android:textColor="#FFFFFF"
          android:textSize="16sp" />
</LinearLayout>

now we need to create listview custom view, create new xml called custom.xml and add this code

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="8dp"
        android:orientation="horizontal"
        tools:ignore="UselessParent">

        <TextView
            android:id="@+id/text2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="text"
            android:textSize="16sp"
            android:textStyle="bold"
            android:textColor="#000000"/>
    </LinearLayout>

</LinearLayout>

after that, Create Kotlin Class Called ChatWebSocketClient

import org.java_websocket.client.WebSocketClient
import org.java_websocket.handshake.ServerHandshake
import java.net.URI

// initialize websocket client
class ChatWebSocketClient(serverUri: URI, private val messageListener: (String) -> Unit) : WebSocketClient(serverUri) {

    override fun onOpen(handshakedata: ServerHandshake?) {
        // When WebSocket connection opened
    }

    override fun onClose(code: Int, reason: String?, remote: Boolean) {
        // When WebSocket connection closed
    }

    override fun onMessage(message: String?) {
        // When Receive a message
        messageListener.invoke(message ?: "")
    }

    override fun onError(ex: Exception?) {
        // When An error occurred
    }

    fun sendMessage(message: String) {
        send(message)
    }
}

Features

  • Realtime Message with 40ms ping.
  • 100% Kotlin Code On Client Side & Server Side.
  • Source Code Is Compatible with any IDE
  • Clean & Simple Code

License

GitHub

View Github