Android WebView err_unknown_url_scheme

You have to set a client in the webview and pass these to an intent

webView.setWebViewClient(new WebViewClient() {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            if( URLUtil.isNetworkUrl(url) ) {
                return false;
            }
            if (appInstalledOrNot(url)) {
                Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
                startActivity( intent );
            } else {
                // do something if app is not installed
            }
            return true;
        }

    });
}

You can have a method to check if app is installed

private boolean appInstalledOrNot(String uri) {
        PackageManager pm = getPackageManager();
        try {
            pm.getPackageInfo(uri, PackageManager.GET_ACTIVITIES);
            return true;
        } catch (PackageManager.NameNotFoundException e) {
        }

        return false;
    }