Kitkat kills: Not allowed to load local resource: file:///android_asset/webkit/android-weberror.png

Question

I have an app that uses WebViews. I\'ve changed my targetAPI from 18 to 19 and I\'m currently testing on the new 4.4. For some reason I\'m getting this error: Not allo

Answer 1

A bit of an intrusive hack, but I worked around this issue by introducing a "unique token" and implementing the WebViewClient with a shouldInterceptRequest override.

First, change the URL from file:///android/asset to a relative path with a uniquely identifying token:

Then, override shouldInterceptRequest as follows:

// Injection token as specified in HTML source
private static final String INJECTION_TOKEN = "**injection**";

webView.setWebViewClient(new WebViewClient() {

    @Override
    public WebResourceResponse shouldInterceptRequest(WebView view, String url) {
        WebResourceResponse response = super.shouldInterceptRequest(view, url);
        if(url != null && url.contains(INJECTION_TOKEN)) {
            String assetPath = url.substring(url.indexOf(INJECTION_TOKEN) + INJECTION_TOKEN.length(), url.length());
            try {
                response = new WebResourceResponse(
                        "application/javascript",
                        "UTF8",
                        getContext().getAssets().open(assetPath)
                );
            } catch (IOException e) {
                e.printStackTrace(); // Failed to load asset file
            }
        }
        return response;
    }
});

This is likely to degrade WebView performance slightly as we are calling the contains() on each resource which is attempted to be loaded, but it's the only workaround I've found to this issue.