How can I fix 'android.os.NetworkOnMainThreadException'?

 

The android.os.NetworkOnMainThreadException occurs when you attempt to perform network operations on the main (UI) thread of an Android application. Performing network operations on the main thread can lead to unresponsive user interfaces and performance issues. To fix this exception, you should move the network operations to a background thread.

One common approach to performing network operations in the background is using the AsyncTask class. However,  using AsyncTask is considered outdated, and it's recommended to use other alternatives like Thread, HandlerThread, or libraries like Kotlin's coroutines or Android's ViewModel.

Here's an example of how you could use the Thread class to perform network operations in the background:

java

import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
    private TextView textView;

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

        textView = findViewById(R.id.textView);

        // Start a background thread for network operations
        Thread backgroundThread = new Thread(new Runnable() {
            @Override
            public void run() {
                // Simulate network operation
                String result = performNetworkOperation();

                // Update UI on the main thread using a Handler
                new Handler(Looper.getMainLooper()).post(new Runnable() {
                    @Override
                    public void run() {
                        textView.setText(result);
                    }
                });
            }
        });
        backgroundThread.start();
    }

    // Simulated network operation
    private String performNetworkOperation() {
        // Perform your network-related code here
        return "Network operation result";
    }
}

In this example, a Thread is used to run the network operation in the background. After the operation is complete, the result is posted to the main thread using a Handler to update the UI.

Keep in mind that the Android ecosystem evolves, and new techniques and best practices might emerge. Using background threads, coroutines, or other asynchronous mechanisms are the recommended ways to handle network operations to avoid the NetworkOnMainThreadException.