了解Android WebView JavaScript界面 [英] Understanding Android webview javascript interface

问题描述

我创建了一个Android WebView ，并使用 addJavascriptInterface(mObject，"jsinterface")注入了 javascript 接口.直到我使用 new 运算符在JavaScript中创建一个具有相同名称(jsinterface)的对象之前，它才能正常工作.

I have created an android WebView, and injected javascript interface using addJavascriptInterface(mObject, "jsinterface"). It works fine until I create an object with same name (jsinterface) in JavaScript using the new operator.

WebView mWebView = findViewById(R.id.myWebView);
mWebView.getSettings().setJavaScriptEnabled(true);
mWebView.setWebChromeClient(new MyWebChromeClient((Activity)mContext));
mWebView.addJavascriptInterface(new testClass(), "jsinterface");
mWebView.loadUrl("UrlToLoad");

testClass.java

public class testClass{
    public testClass() {
    }

    @JavascriptInterface
    public String testNativeMethod() {
        return "Java method called!!";
    }
}

我的Java脚本代码

test.js

function test(msg){
    this.message = msg;

    this.testJSMethod = function(){
        return this.message;
    }
}

alert(jsinterface.testNativeMethod()); // prints Java method called!!
jsinterface= new test("JS method called...");
alert(jsinterface.testJSMethod()); // prints JS method called...
alert(jsinterface.testNativeMethod()); // errors "NPMethod called on non- NPObject"

问题:

javascript 对象是否有可能同时访问 javascript 方法和本机 JAVA 方法(通过 javascriptinterface )吗?是否有可能将任何属性设置为 webview 或执行任何JS script 来完成此操作?

Problem:

Is this possible for a javascript object to have access to both , i.e javascript methods and native JAVA methods(exposed to it via javascriptinterface) ? Is there any possibility of setting any property to webview OR executing any JS script to get this done?

推荐答案

尝试

您可以尝试制作另一个对象，该对象将重新转换对javascript接口的调用.在 WebViewClient 中实施 onPageStarted 方法，并在 onPageStarted 方法，如下所示.

TRY

You may try to make another object, which will retranslate calls to javascript interface.Implement onPageStarted method in WebViewClient , and inject javascript in onPageStarted method, in the following way.

 mWebView.setWebViewClient(new WebViewClient() {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return true;
        }
        @Override
        public void onPageStarted (WebView view, String url, Bitmap favicon){
            String jsScript= "javascript:var functions_array = ['testNativeMethod'];";
                   jsScript+="var jsinterface = {};"
                   jsScript+="functions_array.map(function(id){"
                   jsScript+="jsinterface[id]= function() {"
                   jsScript+="try{return temp_obj[id].apply(temp_obj, arguments);}"
                   jsScript+="catch(e) { console.log('ERROR: ' + e + ', method ' + id);"
                   jsScript+="return false;}}})"
            view.loadUrl(jsScript);
        }
    });

希望这会有所帮助:-)

Hope this helps :-)

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