I want to add to code given by VelocityPulse
I found that following was required in manifest section of AndroidManifest.xml

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

Also you need to add following

val policy = ThreadPolicy.Builder().permitAll().build()
StrictMode.setThreadPolicy(policy)

just after 'super.onCreate(savedInstanceState)' in 'override fun onCreate(savedInstanceState: Bundle?)'

Thanks