如何在Nativescript中通过Buttonclick刷新Webview

<Page xmlns="http://schemas.nativescript.org/tns.xsd" loaded="pageLoaded">
  <StackLayout>
    <Button text="刷新" tap="{{ refreshWebView }}" />
    <WebView src="{{ webViewSrc }}" />
  </StackLayout>
</Page>

const observableModule = require("tns-core-modules/data/observable");
const webViewInterfaceModule = require("nativescript-webview-interface");

function createViewModel() {
  const viewModel = observableModule.fromObject({
    webViewSrc: "https://www.example.com",
    refreshWebView: function() {
      webViewInterface.reloadWebView();
    }
  });

  const webViewInterface = new webViewInterfaceModule.WebViewInterface(webView, "~/www/index.html");

  return viewModel;
}

exports.pageLoaded = function(args) {
  const page = args.object;
  page.bindingContext = createViewModel();
}