Comprobar Internet Android Studio

En tu Manifests:

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

En tu Activity:

ConnectivityManager connectivityManager = (ConnectivityManager) 

getSystemService(Context.CONNECTIVITY_SERVICE); 

NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo(); 

 if (networkInfo != null && networkInfo.isConnected()) { 

 //no hay internet

     }else{

//si hay internet

}