Checking Internet Connection Availability in Android

Using ConnectivityManager class we can detect Internet connection availability in Android.

Code:

ConnectionDetector.java

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
  
public class ConnectionDetector {
  
    private Context _context;
  
    public ConnectionDetector(Context context){
        this._context = context;
    }
  
    /**
     * Checking for all possible internet providers
     * **/
    public boolean isConnectingToInternet(){
        ConnectivityManager connectivity = (ConnectivityManager) _context.getSystemService(Context.CONNECTIVITY_SERVICE);
          if (connectivity != null)
          {
              NetworkInfo[] info = connectivity.getAllNetworkInfo();
              if (info != null)
                  for (int i = 0; i < info.length; i++)
                      if (info[i].getState() == NetworkInfo.State.CONNECTED)
                      {
                          return true;
                      }
  
          }
          return false;
    }
}

MainActivity.java

import android.os.Bundle;
import android.app.Activity;
import android.view.View;

public class MainActivity extends Activity {
 // Connection detector class
 ConnectionDetector cd;
 // flag for Internet connection status
 Boolean isInternetPresent = false;
 // Alert Dialog Manager
 ShowAlert alert = new ShowAlert();

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  cd = new ConnectionDetector(getApplicationContext());
 }

 public void checkavailability(View v) {
  // Check if Internet present
  isInternetPresent = cd.isConnectingToInternet();
  if (!isInternetPresent) {
   // Internet Connection is not present
   alert.showAlertDialog(MainActivity.this,
     "Fail",
     "Internet Connection is NOT Available", false); 
   // stop executing code by return
   return;
  } else {
   // Internet Connection is not present
   alert.showAlertDialog(MainActivity.this,
     "Success",
     "Internet Connection is Available", true);
   // stop executing code by return
   return;
  }
 }
}

ShowAlert.java

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
 
public class ShowAlert {
    /** 
     * Function to display simple Alert Dialog
     * @param context - application context
     * @param title - alert dialog title
     * @param message - alert message
     * @param status - success/failure (used to set icon)
     *               - pass null if you don't want icon
     * */
 public void showAlertDialog(Context context, String title, String message,
            Boolean status) {
//        AlertDialog alertDialog = new AlertDialog.Builder(context).create();
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        // Setting Dialog Title
        builder.setTitle(title);
 
        // Setting Dialog Message
        builder.setMessage(message);
 
        if(status != null)
            // Setting alert dialog icon
         builder.setIcon((status) ? R.drawable.success : R.drawable.fail);
 
        // Setting OK Button
        builder.setNegativeButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
            }
        });
 
        // Showing Alert Message
        builder.show();
    }
}

And your
activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/button1"
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:onClick="checkavailability"
        android:text="Check Internet Availability" />

</RelativeLayout>

And don't forget to add these permissions in your Manifest file.

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

Screen Shots

I hope this post is useful. kindly share your feedback as comment here.

Thank You