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How to handle WebSocket connection errors in Kotlin Android

How to handle WebSocket connection errors in Kotlin Android.

Here's a detailed step-by-step tutorial on how to handle WebSocket connection errors in Kotlin Android:

Step 1: Add WebSocket dependency​

Start by adding the necessary dependency for WebSocket support in your Android project. Open your app-level build.gradle file and add the following line in the dependencies block:

implementation 'org.java-websocket:Java-WebSocket:1.5.1'

Sync your project to download the required dependencies.

Step 2: Create WebSocket connection​

Create a class to handle WebSocket connection. This class will represent the WebSocket client and handle the connection and communication with the server. Here's an example implementation:

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

class MyWebSocketClient(serverUri: URI) : WebSocketClient(serverUri) {

    override fun onOpen(handshakedata: ServerHandshake?) {
        // WebSocket connection has been successfully established
        // You can perform any necessary tasks here
    }

    override fun onMessage(message: String?) {
        // Handle incoming WebSocket messages
        // You can parse and process the received message here
    }

    override fun onClose(code: Int, reason: String?, remote: Boolean) {
        // WebSocket connection has been closed
        // You can perform any necessary cleanup tasks here
    }

    override fun onError(ex: Exception?) {
        // Handle WebSocket connection errors
        // You can display an error message or try to reconnect here
    }
}

Step 3: Connect to WebSocket server​

Create an instance of the WebSocket client and connect to the WebSocket server. Here's an example:

val serverUri = URI("wss://your-websocket-server.com")
val client = MyWebSocketClient(serverUri)
client.connect()

Make sure to replace "wss://your-websocket-server.com" with the actual WebSocket server URL.

Step 4: Handle WebSocket connection errors​

In the onError method of the MyWebSocketClient class, you can handle WebSocket connection errors. This method is called when any error occurs during the WebSocket connection. Here's an example implementation:

override fun onError(ex: Exception?) {
    // Handle WebSocket connection errors
    if (ex != null) {
        ex.printStackTrace()
        // Display an error message to the user
        // You can show a Toast or update a TextView with the error message
    }
    // Try to reconnect to the WebSocket server
    reconnect()
}

private fun reconnect() {
    // Implement your own reconnect logic here
    // You can wait for a certain period and then call client.connect() again
}

In the onError method, you can display an error message to the user using a Toast or by updating a TextView with the error message. Additionally, you can implement your own reconnect logic in the reconnect method. For example, you can wait for a certain period and then call client.connect() again to establish a new WebSocket connection.

Step 5: Test WebSocket connection errors​

To test the WebSocket connection error handling, you can simulate a connection error by disconnecting from the network or using an invalid WebSocket server URL. Run your Android app and observe the onError method being called when a connection error occurs.

That's it! You have now learned how to handle WebSocket connection errors in Kotlin Android. You can customize the error handling and reconnect logic based on your specific requirements.