stringByEvaluatingJavascriptFromString (iOS method, what is Android equivalent?)

Question

In an iOS app, I used

stringFromJavaScript = [webView stringByEvaluatingJavascriptFromString:@"document.getElementById(\"image\").getAttribute(\"src")"];

To get the src directory of the image that was being displayed on the webView. I want to do the same for Android. What are my options?

Basically the intent is to capture the path so that I can email this same picture...

ie.

"picture.php?image=%@",stringFromJavascript

This way, that same image would be loaded when the user clicks the link, or posts it to facebook etc.

Quern

Something like this may be the right track, however I would like to get the element as a String to use in the code lexandera.com/2009/01/injecting-javascript-into-a-webview – Quern

The silly part is that WebView.loadURL() apparently uses stringByEvaluatingJavascriptFromString() internally when the URL scheme is javascript. github.com/android/platform_frameworks_base/blob/master/core/… – Shaynashayne

You could use this method in Android via reflection, please visit https://mcmap.net/q/822349/-exist-stringbyevaluatingjavascriptfromstring-for-android – Weinberg

Answer 1

Yeah, I miss this method greatly in Android ;)

To execute JavaScript and get response you can do as follows:

1. Define JavaScript callback interface in your code:

   class MyJavaScriptInterface {
       @JavascriptInterface
       public void someCallback(String jsResult) {
            // your code...
       }
   }
   

2. Attach this callback to your WebView

   MyJavaScriptInterface javaInterface = new MyJavaScriptInterface();
   yourWebView.addJavascriptInterface(javaInterface, "HTMLOUT");
   

3. Run your JavaScript calling window.HTMLOUT.someCallback from the script:

   yourWebView.loadUrl("javascript:( function () { var resultSrc = document.getElementById(\"image\").getAttribute(\"src\"); window.HTMLOUT.someCallback(resultSrc); } ) ()");
   

Hope this helps!

Penchant

thank you so much! this works fantastic! too bad its so much more tedious than the iOS method! Though i suppose a bit more flexible! :) – Quern

+1 because you explained the idea clearly, i could not understand the concept from the other websites... – Banks

Hi,i am getting Uncaught TypeError, please check the error.[INFO:CONSOLE(1)] "Uncaught TypeError: Cannot call method 'someCallback' of undefined", source: (1) – Tuna