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

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

    if(netInfo == null || !netInfo.isConnected() || !netInfo.isAvailable()){
        Toast.makeText(context, "No Internet connection!", Toast.LENGTH_LONG).show();
        return false;
    }
return true; 
}

And you must add premission for accessing network state and Internet:

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

Answer 2

public boolean isOnline() 
{


ConnectivityManager connectionManager;

if(app_context!=null)

connectionManager = (ConnectivityManager) app_context.getSystemService(Context.CONNECTIVITY_SERVICE);

        else
            return false;

        try 
        {
            if (connectionManager.getActiveNetworkInfo().isConnected()) 
            {
                Log.e(THIS_FILE, "Communicator ....isConnected()");
                return true;
            } 
            else
            { 
                Log.e(THIS_FILE, "Communicator ....isNotConnected()");
                return false;
            }
        } 
        catch (NullPointerException e) 
        {
            Log.e(THIS_FILE, "No Active Connection");
            return false;
        }
    }

set permission in manifest

<uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Answer 3

try this

ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        android.net.NetworkInfo wifi = cm
                .getNetworkInfo(ConnectivityManager.TYPE_WIFI);
        android.net.NetworkInfo datac = cm
                .getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
        if ((wifi != null & datac != null)
                && (wifi.isConnected() | datac.isConnected())) {
                //connection is avlilable
                 }else{
                //no connection
                  Toast toast = Toast.makeText(context, "No Internet Connection",
                Toast.LENGTH_LONG);
        toast.show();  
                }

and don't forget to add following permssions

<uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Answer 4

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;
    }
}

Answer 5

private boolean isNetworkAvailable() {
    ConnectivityManager connectivityManager 
          = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
    return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}

if(!isNetworkAvailable()){
        //Toast.makeText(this, "No Internet Connection", Toast.LENGTH_SHORT).show();
        new AlertDialog.Builder(this)
        .setIcon(android.R.drawable.ic_dialog_alert)
        .setTitle("Closing the App")
        .setMessage("No Internet Connection,check your settings")
        .setPositiveButton("Close", new DialogInterface.OnClickListener()
    {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            finish();    
        }

    })
    .show();
    }

Answer 6

write this code in your create method

if (internetConnection.hasConnection(BankAccount.this))
{
   // call your methods
}

else
{
    AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context, AlertDialog.THEME_DEVICE_DEFAULT_LIGHT);
    alertDialogBuilder
            .setMessage("No internet connection on your device. Would you like to enable it?")
            .setTitle("No Internet Connection")
            .setCancelable(false)
            .setPositiveButton(" Enable Internet ",
                    new DialogInterface.OnClickListener()
                    {

                        public void onClick(DialogInterface dialog, int id)
                        {
                            Intent dialogIntent = new Intent(android.provider.Settings.ACTION_SETTINGS);
                            dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                            context.startActivity(dialogIntent);
                        }
                    });

    alertDialogBuilder.setNegativeButton(" Cancel ", new DialogInterface.OnClickListener()
    {
        public void onClick(DialogInterface dialog, int id)
        {
            dialog.cancel();
        }
    });

    AlertDialog alert = alertDialogBuilder.create();
    alert.show();
}