[javascript] Android Calling JavaScript functions in WebView

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.

The javascript function looks like:

function testEcho(message){

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!);" + "})()");

I did enable javascript on the WebView

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

And heres the Java Class

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);

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?

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

This question is related to javascript android webview android-webview

The answer is

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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