Web Chrome Client for Android. Wraps HTML pages for interaction with Native Android functions. Offers locked down wrapper so external URLs don't load.

FullscreenWebChromeClient.java

/**
 * Created by Jon-Luke.West on 4/6/2015.
 */
public class FullscreenWebChromeClient extends WebChromeClient {
    private View mVideoProgressView;
    private View mCustomView;
    private WebView webView;
    private FrameLayout customViewContainer;
    private WebChromeClient.CustomViewCallback customViewCallback;

    public FullscreenWebChromeClient(WebView webView, FrameLayout viewContainer) {
        super();

        this.webView = webView;
        customViewContainer = viewContainer;
    }

    @Override
    public void onShowCustomView(View view, CustomViewCallback callback) {

        // if a view already exists then immediately terminate the new one
        if (mCustomView != null) {
            callback.onCustomViewHidden();
            return;
        }
        mCustomView = view;
        webView.setVisibility(View.GONE);
        customViewContainer.setVisibility(View.VISIBLE);
        customViewContainer.addView(view);
        customViewCallback = callback;
    }

    @Override
    public void onHideCustomView() {
        super.onHideCustomView();    //To change body of overridden methods use File | Settings | File Templates.
        if (mCustomView == null)
            return;

        webView.setVisibility(View.VISIBLE);
        customViewContainer.setVisibility(View.GONE);

        // Hide the custom view.
        mCustomView.setVisibility(View.GONE);

        // Remove the custom view from its container.
        customViewContainer.removeView(mCustomView);
        customViewCallback.onCustomViewHidden();

        mCustomView = null;
    }
}

LockedWebViewClient.java

/**
 * Created by Jon-Luke.West on 4/6/2015.
 */
public class LockedWebViewClient extends WebViewClient {
    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
        return true; //This object will handle the request and do nothing with it
    }
}

WebAppInterface.java

/**
 * Created by Jon-Luke.West on 3/4/2016.
 */
public class WebAppInterface {
    Context mContext;

    /** Instantiate the interface and set the context */
    WebAppInterface(Context c) {
        mContext = c;
    }

    /** Show a toast from the web page */
    @JavascriptInterface
    public void testToast() {
        Toast.makeText(mContext, "Connection Successful", Toast.LENGTH_SHORT).show();
    }
}

WebFragment.java

/**
 * Created by Jon-Luke.West on 4/6/2015.
 */
public class WebFragment extends Fragment {

    private WebView webContent;
    private String htmlCode = null;

    public WebFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        //Inflate the layout
        View rootView = inflater.inflate(R.layout.webwrapper_main, container, false);

        //Get handles to the fullscreenFrame and WebView container
        FrameLayout viewContainer = (FrameLayout) rootView.findViewById(R.id.fullscreenFrame);
        webContent = (WebView) rootView.findViewById(R.id.web_content);

        //Makes Javascript work
        WebSettings settings = webContent.getSettings();
        settings.setJavaScriptEnabled(true);
        settings.setDomStorageEnabled(true);

        //Set JavaScriptInterface
        webContent.addJavascriptInterface(new WebAppInterface(getActivity().getApplicationContext()), "Android");
        //Handles fullscreen video
        webContent.setWebChromeClient(new FullscreenWebChromeClient(webContent,viewContainer));
        //Handles overriding links to external web content
        webContent.setWebViewClient(new LockedWebViewClient());
        //Hides the scroll bars
        webContent.setVerticalScrollBarEnabled(false);
        webContent.setHorizontalScrollBarEnabled(false);

        Bundle bundle = this.getArguments();
        if (bundle != null) {
            htmlCode = bundle.getString("com.jldubz.webwrapper.html");

            if (htmlCode != null) {
                webContent.loadUrl(htmlCode);
            } else {
                webContent.loadUrl("about:blank");
            }
        } else {
            webContent.loadUrl("about:blank");
        }

        return rootView;
    }

    @Override
    public void onPause() {
        //Kills all WebView threads to avoid resource consumption while the activity is not running
        webContent.loadUrl("about:blank");
        super.onPause();
    }

    @Override
    public void onResume() {
        if (htmlCode != null) {
            webContent.loadUrl(htmlCode);
        }
        super.onResume();
    }
}

test

test