private void makeTextBigger() {
    WebSettings settings = webview.getSettings();
    settings.setTextZoom(settings.getTextZoom() + 10);
}

webview.setWebViewClient(new WebViewClient(){
        public void onPageStarted(WebView wv, String url, Bitmap favicon){
            show_WebviewLoadingProgressBar();
        }

        public void onPageFinished(WebView wv, String thisUrl){
            hide_WebviewLoadingProgressBar();
        }
    });