Android 在 WebView 中调用 JavaScript 函数 [英] Android Calling JavaScript functions in WebView

问题描述

我正在尝试调用一些 javascript 函数，这些函数位于在 android webview 中运行的 html 页面中.下面的代码尝试执行的操作非常简单 - 从 android 应用程序中，调用带有测试消息的 javascript 函数，该函数又调用回通过 toast 显示测试消息的 android 应用程序中的 java 函数.

I am trying to call some javascript functions sitting in an html page running inside an android webview. Pretty simple what the code tries to do below - from the android app, call a javascript function with a test message, which inturn calls a java function back in the android app that displays test message via toast.

javascript 函数如下所示:

The javascript function looks like:

function testEcho(message){
     window.JSInterface.doEchoTest(message);
}

从 WebView，我尝试通过以下方式调用 javascript，但没有成功:

From the WebView, I have tried calling the javascript the following ways with no luck:

myWebView.loadUrl("javascript:testEcho(Hello World!)");
mWebView.loadUrl("javascript:(function () { " + "testEcho(Hello World!);" + "})()");

我确实在 WebView 上启用了 javascript

I did enable javascript on the WebView

myWebView.getSettings().setJavaScriptEnabled(true);
// register class containing methods to be exposed to JavaScript
myWebView.addJavascriptInterface(myJSInterface, "JSInterface"); 

这里是 Java 类

public class JSInterface{

private WebView mAppView;
public JSInterface  (WebView appView) {
        this.mAppView = appView;
    }

    public void doEchoTest(String echo){
        Toast toast = Toast.makeText(mAppView.getContext(), echo, Toast.LENGTH_SHORT);
        toast.show();
    }
}

我花了很多时间在谷歌上搜索，看看我可能做错了什么.我发现的所有示例都使用这种方法.有人看到这里有什么问题吗?

I've spent a lot of time googling around to see what I may be doing wrong. All examples I have found use this approach. Does anyone see something wrong here?

还有其他几个外部 javascript 文件被引用 &在 html 中使用，它们可能是问题吗?

There are several other external javascript files being referenced & used in the html, could they be the issue?

推荐答案

我发现了问题所在:testEcho() 参数中缺少引号.这就是我接到工作电话的方式:

I figured out what the issue was : missing quotes in the testEcho() parameter. This is how I got the call to work:

myWebView.loadUrl("javascript:testEcho('Hello World!')");

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