android webview splash

MainActivity.kt

import kotlinx.android.synthetic.main.activity_main.webview;
import kotlinx.android.synthetic.main.activity_main.splash;

class MainActivity : Activity() {

    private class MyWebViewClient() : WebViewClient() {
        override fun onPageFinished(view: WebView?, url: String?) {
            super.onPageFinished(view, url)
          
            splash.setVisibility(View.INVISIBLE); // can't call function on this reference
        }
    }
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        webview.webViewClient = MyWebViewClient()
        webview.loadUrl("https://example.com")
    }
  
}