java.lang.IllegalStateException: Calling View methods on another thread than the UI thread

what's your code like? you can try

 runOnUiThread(new Runnable() {
        @Override
        public void run() {

            // TODO Your code
        }
    });

just check migrating web view of 4.4 google added and changed some things in it here

runOnUiThread(new Runnable() {
    @Override
    public void run() {
        // Code for WebView goes here
    }
});


// This code is BAD and will block the UI thread
webView.loadUrl("javascript:fn()");
while(result == null) {
  Thread.sleep(100);
}