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.

Something like this may be the right track, however I would like to get the element as a String to use in the code http://lexandera.com/2009/01/injecting-javascript-into-a-webview/ — rjfellman, Apr 24 '12 at 20:33
The silly part is that `WebView.loadURL()` apparently uses `stringByEvaluatingJavascriptFromString()` internally when the URL scheme is `javascript`. https://github.com/android/platform_frameworks_base/blob/master/core/java/android/webkit/BrowserFrame.java#L262 — JAB, Jun 20 '13 at 18:28
You could use this method in Android via reflection, please visit http://stackoverflow.com/a/17830417/2442753 — Jonny Chen, Jul 24 '13 at 09:58

score 38 · Accepted Answer · edited Jan 15 '15 at 05:47

38

Yeah, I miss this method greatly in Android ;)

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

Define JavaScript callback interface in your code:

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

Attach this callback to your WebView

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

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!

edited Jan 15 '15 at 05:47

Lachlan Goodhew-Cook

1,081
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answered Apr 27 '12 at 11:08

Łukasz Sromek

3,567
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1

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! :) – rjfellman Apr 27 '12 at 20:39
Thank you very much, it saves my time :) – Abu Sadat Mohammed Yasin Feb 10 '13 at 18:02
+1 because you explained the idea clearly, i could not understand the concept from the other websites... – TMMDev Jun 15 '14 at 12:04
2

Hi,i am getting Uncaught TypeError, please check the error.[INFO:CONSOLE(1)] "Uncaught TypeError: Cannot call method 'someCallback' of undefined", source: (1) – Ravikumar11 Jul 16 '14 at 04:51

stringByEvaluatingJavascriptFromString (iOS method, what is Android equivalent?)

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