static final boolean DEVELOPING_MOBILE_WEB_UI = false;
static final String DEVEL_SERVER = "http://192.168.0.110:8080"; // modify it!

static final String LOG_TAG = "WebApp";

public WebView wv;
private AndroidAPIsForJavascript android_js;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    this.requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.activity_main);

    this.wv = (WebView) findViewById(R.id.webView);
    overrideLinkOpening();
    wv.getSettings().setJavaScriptEnabled(true);
    exposeJavascriptAPI();
    logJavascriptConsoleAPI();
    disableScrolling();

    String url;
    if (DEVELOPING_MOBILE_WEB_UI) {
        //            url = DEVEL_SERVER + "/recommendations";
        url = DEVEL_SERVER;
    } else {
        url = "file:///android_asset/index.html";
    }
    wv.loadUrl(url);
}

private void overrideLinkOpening() {
    // Control which links open in the system browser
    // related: onKeyDown overrides back button navigation
    this.wv.setWebViewClient(new PlateWebViewClient());
}

private class PlateWebViewClient extends WebViewClient {
    @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            if (Uri.parse(url).getScheme().equals("file")) {
                return false;
            } else {
                // Otherwise, the link is not for a page on my site, so launch another Activity that handles URLs
                Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
                startActivity(intent);
                return true;
            }
        }
}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if ((keyCode == KeyEvent.KEYCODE_BACK) && this.wv.canGoBack()) {
        Log.i(LOG_TAG, "goBack: " + this.wv.getUrl());
        this.wv.goBack();
        return true;
    }
    // If it wasn't the Back key or there's no web page history, bubble up to the default
    // system behavior (probably exit the activity)
    return super.onKeyDown(keyCode, event);
}

private void exposeJavascriptAPI() {
    // Expose "AndroidAPIsForJavascript" under the name "Android"
    if (this.android_js == null)
        this.android_js = new AndroidAPIsForJavascript(this);
    this.wv.addJavascriptInterface(this.android_js, "Android");
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

private void logJavascriptConsoleAPI() {
    this.wv.setWebChromeClient(new WebChromeClient() {
            public boolean onConsoleMessage(ConsoleMessage cm) {
            Log.d(LOG_TAG, cm.message() + " -- From line "
                + cm.lineNumber() + " of "
                + cm.sourceId() );
            return true;
            }
            });
}

private void disableScrolling() {
    // don't draw scroll bars
    this.wv.setHorizontalScrollBarEnabled(false);
    this.wv.setVerticalScrollBarEnabled(false);
    // NOTE: content may still scroll if over sized
}

private static final String TAG = MainActivity.LOG_TAG;
MainActivity activity;
Context ctx;

AndroidAPIsForJavascript(MainActivity a) {
    this.activity = a;
    this.ctx = a.getApplication();
}

@JavascriptInterface
public String getPhoneNumber() {
    // requires android.permission.READ_PHONE_STATE
    // NOTE: may return null or ""
    TelephonyManager tm = (TelephonyManager)ctx.getSystemService(Context.TELEPHONY_SERVICE);
    String t =  tm.getLine1Number();
    return t;
}

@JavascriptInterface
public void test() {
    Log.v(TAG, "test");
}