Check for Active Internet Connection Android

How to test for active internet connection in android

Follow below code to check properly Internet is available or not as well as active or not.

   //I have taken dummy icon from server, so it may be removed in future. So you can place one small icon on server and then access your own URL.

1. Specify Permission in manifest file, also make sure for marshmellwo runtime permission handle. As I am not going to show reuntime permission here.

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

2. Check for Internet Availibility and the State as Active or Inactive.

        public class InternetDemo extends Activity
        {
            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);

                checkInternetAvailibility();
            }

            public void checkInternetAvailibility()
            {
                if(isInternetAvailable())
                {
                    new IsInternetActive().execute();
                }
                else {
                    Toast.makeText(getApplicationContext(), "Internet Not Connected", Toast.LENGTH_LONG).show();
                }
            }

            public boolean isInternetAvailable() {
                try {
                    ConnectivityManager connectivityManager
                            = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
                    NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
                    return activeNetworkInfo != null && activeNetworkInfo.isConnected();
                } catch (Exception e) {

                    Log.e("isInternetAvailable:",e.toString());
                    return false;
                }
            }

            class IsInternetActive extends AsyncTask<Void, Void, String>
            {
                InputStream is = null;
                String json = "Fail";

                @Override
                protected String doInBackground(Void... params) {
                    try {
                        URL strUrl = new URL("http://icons.iconarchive.com/icons/designbolts/handstitch-social/24/Android-icon.png");
                        //Here I have taken one android small icon from server, you can put your own icon on server and access your URL, otherwise icon may removed from another server.

                        URLConnection connection = strUrl.openConnection();
                        connection.setDoOutput(true);
                        is =  connection.getInputStream();
                        json = "Success";

                    } catch (Exception e) {
                        e.printStackTrace();
                        json = "Fail";
                    }
                    return json;

                }

                @Override
                protected void onPostExecute(String result) {
                    if (result != null)
                    {
                       if(result.equals("Fail"))
                       {
                           Toast.makeText(getApplicationContext(), "Internet Not Active", Toast.LENGTH_LONG).show();
                       }
                       else
                       {
                           Toast.makeText(getApplicationContext(), "Internet Active " + result, Toast.LENGTH_LONG).show();
                       }
                    }
                    else
                    {
                        Toast.makeText(getApplicationContext(), "Internet Not Active", Toast.LENGTH_LONG).show();
                    }
                }

                @Override
                protected void onPreExecute() {
                    Toast.makeText(getBaseContext(),"Validating Internet",Toast.LENGTH_LONG).show();
                    super.onPreExecute();
                }
            }
        }

android studio How to continuously check if there is an active internet connection

You can use Runnable and post it using handler to continuously check internet connection every 5 second. Declare a global boolean variable isConnected and create a Runnable like:

private var isActiveNetwork= object : Runnable {
        override fun run() {
            try {
                if(InetAddress.getByName("www.google.com").isReachable(5000)) 
                 {
                  isConnected = true
                 }            
               else{
                  isConnected = false
                 }
               Handler().postDelayed(this,5000) 
              } 
          catch (e: Exception) {
              isConnected = false
         }

        }
    }

Now you can start this Runnable from network request callback:

 override fun onAvailable(network: Network) {
            super.onAvailable(network)
            Handler().post(isActiveNetwork)
        }

Android check internet connection

This method checks whether mobile is connected to internet and returns true if connected:

private boolean isNetworkConnected() {
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

    return cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnected();
}

in manifest,

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

Edit:
This method actually checks if device is connected to internet(There is a possibility it's connected to a network but not to internet).

public boolean isInternetAvailable() {
    try {
        InetAddress ipAddr = InetAddress.getByName("google.com"); 
        //You can replace it with your name
            return !ipAddr.equals("");

        } catch (Exception e) {
            return false;
    }
}

Android Internet connectivity check better method

Try this:

It's really simple and fast:

public boolean isInternetAvailable(String address, int port, int timeoutMs) {
    try {
        Socket sock = new Socket();
        SocketAddress sockaddr = new InetSocketAddress(address, port);

        sock.connect(sockaddr, timeoutMs); // This will block no more than timeoutMs
        sock.close();

        return true;

    } catch (IOException e) { return false; }
}

Then wherever you want to check just use this:

if (isInternetAvailable("8.8.8.8", 53, 1000)) {
     // Internet available, do something
} else {
     // Internet not available
}

How to check internet access on Android? InetAddress never times out

Network connection / Internet access

• isConnectedOrConnecting() (used in most answers) checks for any network connection
• To know whether any of those networks have internet access, use one of the following

A) Ping a Server (easy)

// ICMP 
public boolean isOnline() {
    Runtime runtime = Runtime.getRuntime();
    try {
        Process ipProcess = runtime.exec("/system/bin/ping -c 1 8.8.8.8");
        int     exitValue = ipProcess.waitFor();
        return (exitValue == 0);
    }
    catch (IOException e)          { e.printStackTrace(); }
    catch (InterruptedException e) { e.printStackTrace(); }

    return false;
}

+ could run on main thread

- does not work on some old devices (Galays S3, etc.), it blocks a while if no internet is available.

B) Connect to a Socket on the Internet (advanced)

// TCP/HTTP/DNS (depending on the port, 53=DNS, 80=HTTP, etc.)
public boolean isOnline() {
    try {
        int timeoutMs = 1500;
        Socket sock = new Socket();
        SocketAddress sockaddr = new InetSocketAddress("8.8.8.8", 53);

        sock.connect(sockaddr, timeoutMs);
        sock.close();

        return true;
    } catch (IOException e) { return false; }
}

+ very fast (either way), works on all devices, very reliable

- can't run on the UI thread

This works very reliably, on every device, and is very fast. It needs to run in a separate task though (e.g. ScheduledExecutorService or AsyncTask).

Possible Questions

• Is it really fast enough?

  Yes, very fast ;-)

• Is there no reliable way to check internet, other than testing something on the internet?

  Not as far as I know, but let me know, and I will edit my answer.

• What if the DNS is down?

  Google DNS (e.g. 8.8.8.8) is the largest public DNS in the world. As of 2018 it handled over a trillion queries a day [1]. Let 's just say, your app would probably not be the talk of the day.

• Which permissions are required?

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

  Just internet access - surprise ^^ (Btw have you ever thought about, how some of the methods suggested here could even have a remote glue about internet access, without this permission?)

 

Extra: One-shot RxJava/RxAndroid Example (Kotlin)

fun hasInternetConnection(): Single<Boolean> {
  return Single.fromCallable {
    try {
      // Connect to Google DNS to check for connection
      val timeoutMs = 1500
      val socket = Socket()
      val socketAddress = InetSocketAddress("8.8.8.8", 53)
    
      socket.connect(socketAddress, timeoutMs)
      socket.close()
  
      true
    } catch (e: IOException) {
      false
    }
  }
  .subscribeOn(Schedulers.io())
  .observeOn(AndroidSchedulers.mainThread())
}

///////////////////////////////////////////////////////////////////////////////////
// Usage

    hasInternetConnection().subscribe { hasInternet -> /* do something */}

Extra: One-shot RxJava/RxAndroid Example (Java)

public static Single<Boolean> hasInternetConnection() {
    return Single.fromCallable(() -> {
        try {
            // Connect to Google DNS to check for connection
            int timeoutMs = 1500;
            Socket socket = new Socket();
            InetSocketAddress socketAddress = new InetSocketAddress("8.8.8.8", 53);

            socket.connect(socketAddress, timeoutMs);
            socket.close();

            return true;
        } catch (IOException e) {
            return false;
        }
    }).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread());
}

///////////////////////////////////////////////////////////////////////////////////
// Usage

    hasInternetConnection().subscribe((hasInternet) -> {
        if(hasInternet) {

        }else {

        }
    });

Extra: One-shot AsyncTask Example

Caution: This shows another example of how to do the request. However, since AsyncTask is deprecated, it should be replaced by your App's thread scheduling, Kotlin Coroutines, Rx, ...

class InternetCheck extends AsyncTask<Void,Void,Boolean> {

    private Consumer mConsumer;
    public  interface Consumer { void accept(Boolean internet); }

    public  InternetCheck(Consumer consumer) { mConsumer = consumer; execute(); }

    @Override protected Boolean doInBackground(Void... voids) { try {
        Socket sock = new Socket();
        sock.connect(new InetSocketAddress("8.8.8.8", 53), 1500);
        sock.close();
        return true;
    } catch (IOException e) { return false; } }

    @Override protected void onPostExecute(Boolean internet) { mConsumer.accept(internet); }
}

///////////////////////////////////////////////////////////////////////////////////
// Usage

    new InternetCheck(internet -> { /* do something with boolean response */ });

Detect if Android device has Internet connection

You are right. The code you've provided only checks if there is a network connection.
The best way to check if there is an active Internet connection is to try and connect
to a known server via http.

public static boolean hasActiveInternetConnection(Context context) {
    if (isNetworkAvailable(context)) {
        try {
            HttpURLConnection urlc = (HttpURLConnection) (new URL("http://www.google.com").openConnection());
            urlc.setRequestProperty("User-Agent", "Test");
            urlc.setRequestProperty("Connection", "close");
            urlc.setConnectTimeout(1500); 
            urlc.connect();
            return (urlc.getResponseCode() == 200);
        } catch (IOException e) {
            Log.e(LOG_TAG, "Error checking internet connection", e);
        }
    } else {
        Log.d(LOG_TAG, "No network available!");
    }
    return false;
}

Of course you can substitute the http://www.google.com URL for any other server you want to connect to, or a server you know has a good uptime.

As Tony Cho also pointed out in this comment below, make sure you don't run this code on the main thread, otherwise you'll get a NetworkOnMainThread exception (in Android 3.0 or later). Use an AsyncTask or Runnable instead.

If you want to use google.com you should look at Jeshurun's modification. In his answer he modified my code and made it a bit more efficient. If you connect to

HttpURLConnection urlc = (HttpURLConnection) 
            (new URL("http://clients3.google.com/generate_204")
            .openConnection());

and then check the responsecode for 204

return (urlc.getResponseCode() == 204 && urlc.getContentLength() == 0);

then you don't have to fetch the entire google home page first.

Android Check Internet connection continuously

I want to use it in every activity. How can I modify this code?

Create a BaseActivity class which extends AppCompatActivity, and then make all of your Activity classes extend this BaseActivity class. Put your code to check internet connection in the BaseActivity class. cheers :)

Detect whether there is an Internet connection available on Android

The getActiveNetworkInfo() method of ConnectivityManager returns a NetworkInfo instance representing the first connected network interface it can find or null if none of the interfaces are connected. Checking if this method returns null should be enough to tell if an internet connection is available or not.

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

You will also need:

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

in your android manifest.

Edit:

Note that having an active network interface doesn't guarantee that a particular networked service is available. Network issues, server downtime, low signal, captive portals, content filters and the like can all prevent your app from reaching a server. For instance you can't tell for sure if your app can reach Twitter until you receive a valid response from the Twitter service.

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