Call Java function from JavaScript over Android WebView

Your function returns 'true'. That makes the 'onclick' property of your HTML code equal to true, hence the button remains 'clicked.'

I don't think this is the best solution to get the javascript to execute java code. See here:

If you want to expose native code to the HTML to be callable via javascript, do the following around your web view declaration:

JavaScriptInterface jsInterface = new JavaScriptInterface(this);
webView.getSettings().setJavaScriptEnabled(true);
webView.addJavascriptInterface(jsInterface, "JSInterface");

Declare the class JavaScriptInterface:

public class JavaScriptInterface {
    private Activity activity;

    public JavaScriptInterface(Activity activity) {
        this.activity = activity;
    }

    @JavascriptInterface
    public void startVideo(String videoAddress){
        Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setDataAndType(Uri.parse(videoAddress), "video/3gpp"); 
        activity.startActivity(intent);
    }
}

I am declaring a single function for playing a video, but you can do whatever you want.

Finally you call this in the WebView contents via simple javascript call:

<video width="320" height="240" controls="controls" poster='poster.gif'
       onclick="window.JSInterface.startVideo('file:///sdcard/test.3gp');" >
   Your browser does not support the video tag.
</video>

The example is taken from another answer of mine, about playing videos, but should be explaining enough.

EDIT As per @CedricSoubrie's comment: if the target version of the application is set to 17 or higher you need to add annotation @JavascriptInterface above each method you want to export to the web view.

The methods defined in the "YourJavaScriptInterface" class, don't forget to annotate each method that you want to expose with "@JavascriptInterface", otherwise the method won't be triggered.

For example, the below code is from the Google Cloud Print JavaScript interface for calls from a webview page:

        final class PrintDialogJavaScriptInterface {
        @JavascriptInterface
        public String toString() { return JS_INTERFACE; }

        @JavascriptInterface
        public String getType() {
            return cloudPrintIntent.getType();
        }

        @JavascriptInterface
        public String getTitle() {
            return cloudPrintIntent.getExtras().getString("title");
        }

        @JavascriptInterface
        public String getContent() {
            try {
                ContentResolver contentResolver = getActivity().getContentResolver();
                InputStream is = contentResolver.openInputStream(cloudPrintIntent.getData());
                ByteArrayOutputStream baos = new ByteArrayOutputStream();

                byte[] buffer = new byte[4096];
                int n = is.read(buffer);
                while (n >= 0) {
                    baos.write(buffer, 0, n);
                    n = is.read(buffer);
                }
                is.close();
                baos.flush();

                return Base64.encodeToString(baos.toByteArray(), Base64.DEFAULT);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return "";
        }

        @JavascriptInterface
        public String getEncoding() {
            return CONTENT_TRANSFER_ENCODING;
        }

        @JavascriptInterface
        public void onPostMessage(String message) {
            if (message.startsWith(CLOSE_POST_MESSAGE_NAME)) {
                finish();
            }
        }
    }