Passing a string from Android to JS in a WebView via @JavascriptInterface-CodePudding

Here is my Javascript interface:

class WebAppInterface(val context: Context){

    @JavascriptInterface
    fun provideAString():String{
        println("executed from js")
        println("this is text")
        return "this is text"
    }

    @JavascriptInterface
    fun printTheString(s:String){
        println(s)
    }
}

Here's how I add it to the WebView:

webView.addJavascriptInterface(WebAppInterface(this), "Android")

Here's how I call the two functions from JS:

function StringFromAndroid(){
    var string=Android.provideAString();
}

...
...

var currentString=new StringFromAndroid();
Android.printTheString(currentString.string);

Here are the print lines:

I/System.out: executed from js  
I/System.out: this is text
I/System.out: undefined

Expected behavior:

Print lines 1 and 2 demonstrate that provideAString() is being called correctly from JS. Print line 3 shows that printTheString(s) is being called correctly from JS, but that the value of currentString.string inside the WebView is "undefined". The expected behavior is that when var currentString=new StringFromAndroid(); forces a call to Android.provideAString(); via the line var string=Android.provideAString();, that call would return the string "this is text" and set var string to have that value so that resultingly, currentString.string would be "this is text" instead of "undefined".

CodePudding user response：

Assign the value of Android.provideAString(); to this:

function StringFromAndroid() {
    this.string = Android.provideAString();
}