Use NetworkCallback In Android

MainActivity.java

package com.app.demo;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {

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


        NetworkUtil.checkNetworkInfo(this, new NetworkUtil.OnConnectionStatusChange() {
            @Override
            public void onChange(boolean type) {
                if(type){
                    Toast.makeText(MainActivity.this, "Connection Available", Toast.LENGTH_SHORT).show();
                }else Toast.makeText(MainActivity.this, "NO Connection", Toast.LENGTH_SHORT).show();
            }
        });

    }
}

NetworkUtil.java

package com.app.demo;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.Network;
import android.net.NetworkCapabilities;
import android.net.NetworkInfo;
import android.os.Build;
import androidx.annotation.NonNull;
public class NetworkUtil {

    public static void checkNetworkInfo(Context context, final OnConnectionStatusChange onConnectionStatusChange){

        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
       if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {

            NetworkCapabilities capabilities = connectivityManager.getNetworkCapabilities(connectivityManager.getActiveNetwork());
            if (capabilities == null){
                onConnectionStatusChange.onChange(false);
            }
            connectivityManager.registerDefaultNetworkCallback(new ConnectivityManager.NetworkCallback(){
                @Override
                public void onAvailable(@NonNull Network network) {
                    onConnectionStatusChange.onChange(true);
                }
                @Override
                public void onLost(@NonNull Network network) {
                    onConnectionStatusChange.onChange(false);
                }
            });

        }
         //for android version below Nougat api 24
        else {

            NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
            onConnectionStatusChange.onChange(networkInfo!= null && networkInfo.isConnectedOrConnecting());
       }
    }

    interface OnConnectionStatusChange{

        void onChange(boolean type);
    }
}