How to get notified when WebView starts loading a new page?

To listen for a web page to start loading you should override onPageStarted, to listen to finish you should override onPageFinished, just to make it more complete use listen for errorsonReceivedError

webView.setWebViewClient(new WebViewClient() {  

        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon){
            super.onPageStarted(view, url, favicon);

            // runs when a page starts loading
            progressBar.setVisibility(View.VISIBLE);
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            super.onPageFinished(view, url);

            // page finishes loading
            progressBar.setVisibility(View.GONE);
        }

        @Override
        public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
            super.onReceivedError(view, request, error);

            // runs when there's a failure in loading page
            progressBar.setVisibility(View.GONE);
            Toast.makeText(context, "Failure on loading web page", Toast.LENGTH_SHORT).show();
        }
});