这个库不再维护了，因为跟webview耦合度太高了，把jsbridge内容分离出来重写了一个plugin

Add JsBridge to the WebView

A Flutter plugin that provides a JsBridge on WebView widget.

On iOS the WebView widget is backed by a WKWebView; On Android the WebView widget is backed by a WebView.

This plugin based on the webview_flutter

Developers Preview Status

To use this plugin on iOS you need to opt-in for the embedded views preview by adding a boolean property to the app's Info.plist file, with the key io.flutter.embedded_views_preview and the value YES.

Keyboard support - not ready for production use

Keyboard support within webviews is experimental. The Android version relies on some low-level knobs that have not been well tested on a broad spectrum of devices yet, and therefore it is not recommended to rely on webview keyboard in production apps yet. See the webview-keyboard for known issues with keyboard input.

Setup

iOS

Opt-in to the embedded views preview by adding a boolean property to the app's Info.plist file with the key io.flutter.embedded_views_preview and the value YES.

Usage

Add bridge_webview_flutter as a dependency in your pubspec.yaml file.

BridgeWebView(
    initialUrl: 'https://flutter.dev',
    javascriptMode: JavascriptMode.unrestricted,
    onWebViewCreated: (WebViewController webViewController) {
        _controller.complete(webViewController);
        webViewController.registerHandler("methodName", response: "r1", onCallBack: (callBackData) {
            print(callBackData.name); // handler name
            print(callBackData.data); // callback data ({'param': '1'})
        });
        webViewController.callHandler("methodName", data: "sendData", onCallBack: (callBackData) {
            print(callBackData.name); // handler name
            print(callBackData.data); // callback data (r2)
        });
    },
    onPageStarted: (String url) {
        print('Page started loading: $url');
    },
    onPageFinished: (String url) {
        print('Page finished loading: $url');
    }
)

Register a Flutter handler function so that js can call

onWebViewCreated: (WebViewController webViewController) {
    _controller.complete(webViewController);
    webViewController.registerHandler("methodName", response: "r1", onCallBack: (callBackData) {
        print(callBackData.name); // handler name
        print(callBackData.data); // callback data ({'param': '1'})
    });
}

js can call this handler method "methodName" through:

WebViewJavascriptBridge.callHandler(
    'methodName'
    , {'param': '1'}
    , function(data) {
        // data is r1
    }
);

Register a JavaScript handler function so that flutter can call

WebViewJavascriptBridge.registerHandler("methodName", function(data, responseCallback) {
    // data is 'sendData'
    responseCallback('r2');
});

flutter can call this js handler function "methodName" through:

onWebViewCreated: (WebViewController webViewController) {
    _controller.complete(webViewController);
    webViewController.callHandler("methodName", data: "sendData", onCallBack: (callBackData) {
        print(callBackData.name); // handler name
        print(callBackData.data); // callback data (r2)
    });
}