#flutter官方webview
webview_flutter: ^0.3.10

 ///初始化webview显示
  Widget _showWebView(BuildContext context) {
    return WebView(
      initialUrl: widget.url,///初始化url
      javascriptMode: JavascriptMode.unrestricted,///JS执行模式
      onWebViewCreated: (WebViewController webViewController) {///在WebView创建完成后调用，只会被调用一次
        //
        //
        _controller.complete(webViewController);
      },
      javascriptChannels: <JavascriptChannel>[///JS和Flutter通信的Channel；
        _alertJavascriptChannel(context),
      ].toSet(),
      navigationDelegate: (NavigationRequest request) {//路由委托（可以通过在此处拦截url实现JS调用Flutter部分）；
        ///通过拦截url来实现js与flutter交互
        if (request.url.startsWith(‘js://webview‘)) {
          Fluttertoast.showToast(msg:‘JS调用了Flutter By navigationDelegate‘);
          print(‘blocking navigation to $request}‘);
          return NavigationDecision.prevent;///阻止路由替换，不能跳转，因为这是js交互给我们发送的消息
        }

        return NavigationDecision.navigate;///允许路由替换
      },
      onPageFinished: (String url) {///页面加载完成回调
        setState(() {
          _loading = false;
        });
        print(‘Page finished loading: $url‘);
      },

    );
  }