Display an alert when internet connection not available in android application

Question

In my application data comes from internet and I am trying to create a function that checks if a internet connection is available or not and if it isn\'t, it gives an alert

Answer 1

Just Try this I am using for my professional app

import androidx.appcompat.app.AlertDialog;

import android.content.DialogInterface;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

public class MainActivity extends AppCompatActivity {    

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

        if (isOnline()) {
             // Do you Stuff
        } else {
            try {
                new AlertDialog.Builder(MainActivity.this)
                        .setTitle("Error")
                        .setMessage("Internet not available, Cross check your internet connectivity and try again later...")
                        .setCancelable(false)
                        .setIcon(android.R.drawable.ic_dialog_alert)
                        .setNeutralButton("OK", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        finish();

                    }
                }).show();
            } catch (Exception e) {
                Log.d(Constants.TAG, "Show Dialog: " + e.getMessage());
            }
        }
    }

    public boolean isOnline() {
        ConnectivityManager conMgr = (ConnectivityManager) getApplicationContext()
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo netInfo = conMgr.getActiveNetworkInfo();

        if(netInfo == null || !netInfo.isConnected() || !netInfo.isAvailable()){
            return false;
        }
        return true;
    }
}