Ejemplo AsyncTask Socket

AsyncTaskSocket.java

import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.Socket;

public class ExampleActivity extends AppCompatActivity {

    private TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textView = findViewById(R.id.textView);

        // Ejecutar AsyncTask
        new SocketAsyncTask().execute("172.172.172.172", "12345", "Hello, Server!");
    }

    private class SocketAsyncTask extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... params) {
            String serverIp = params[0];
            int serverPort = Integer.parseInt(params[1]);
            String messageToSend = params[2];
            StringBuilder response = new StringBuilder();

            try (Socket socket = new Socket(serverIp, serverPort);
                 OutputStream outputStream = socket.getOutputStream();
                 BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()))) {

                // Enviar mensaje al servidor
                outputStream.write(messageToSend.getBytes());
                outputStream.flush();

                // Leer la respuesta del servidor
                String line;
                while ((line = reader.readLine()) != null) {
                    response.append(line).append('\n');
                }

            } catch (Exception e) {
                e.printStackTrace();
                return "Error: " + e.getMessage();
            }
            return response.toString();
        }

        @Override
        protected void onPostExecute(String result) {
            // Actualiza la UI con el resultado
            textView.setText(result);
        }
    }
}