So you have successfully created a webView in your App and already loaded your URL into it.
WebView myWebView = (WebView) findViewById(R.id.webview);
However, any interaction with the page (such as a dropdown menu) will result in BadTokenException crash with the following error message;
FATAL EXCEPTION: main
android.view.WindowManager$BadTokenException: Unable to add window — token is not valid; is your activity running?
This happens when app wants to open a new dialog (e.g. for dropdown menu aka. spinner) while the container activity no longer exists.
Continue reading Fixing BadTokenException in Android WebView