Inject external JS file in Android WebView and call it

Question

I am trying to inject my external JS file (contained in assets dir) into WebView and call it afterwards.

This is the code I use for injecting it:

webView.setWebViewClient(new WebViewClient() {
    @Override
    public void onPageFinished(WebView view, String url) {
        super.onPageFinished(view, url);
        webView.loadUrl("javascript: (function() { "
            + "var script=document.createElement('script');"
            + "script.type='text/javascript';script.src='file://android_asset/js_demo.js';"
            + "document.getElementsByTagName('head').item(0).appendChild(script);"
            + "})()");
        webView.loadUrl("javascript: jsDemo()");
    }
});

When I print the entire content of my WebView, I can see that script tag with src='file://android_asset/js_demo.js' is indeed inserted, but calling function jsDemo does nothing.

NOTE: Function jsDemo is contained in js_demo.js and does nothing clever, just changes some span's color. It work ok since I tested it in browser.

I am convinced I made mistake giving the path to the js file, but I am not sure how to change it in order to make it work. Any help will be appreciated.

Answer 1

Why not just read in the file and execute it directly via loadUrl("javascript:...)?