class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("hud demo"),
      ),
      body: ProgressHud(
        maximumDismissDuration: Duration(seconds: 2),
        child: Center(
          child: Builder(builder: (context) {
            return Column(
              mainAxisSize: MainAxisSize.min,
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                RaisedButton(
                  onPressed: () {
                    _showLoadingHud(context);
                  },
                  child: Text("show loading"),
                ),
              ],
            );
          }),
        ),
      ),
    );
  }
  
  _showLoadingHud(BuildContext context) async {
    ProgressHud.of(context)?.show(ProgressHudType.loading, "loading...");
    await Future.delayed(const Duration(seconds: 1));
    ProgressHud.of(context)?.dismiss();
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  GlobalKey<ProgressHudState> _globalKey = GlobalKey();
  
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("hud demo"),
      ),
      body: ProgressHud(
        key: _globalKey,
        maximumDismissDuration: Duration(seconds: 2),
        child: Center(
          child: Builder(builder: (context) {
            return Column(
              mainAxisSize: MainAxisSize.min,
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                RaisedButton(
                  onPressed: () {
                    _showLoadingHud(context);
                  },
                  child: Text("show loading"),
                ),
              ],
            );
          }),
        ),
      ),
    );
  }

  _showLoadingHud(BuildContext context) async {
    _globalKey.currentState?.show(ProgressHudType.loading, "loading...");
    await Future.delayed(const Duration(seconds: 1));
    _globalKey.currentState?.dismiss();
  }
}

// show successHud with text
_showSuccessHud(BuildContext context) {
  ProgressHud.of(context)?.showAndDismiss(ProgressHudType.success, "load success");
}

// show errorHud with text
_showErrorHud(BuildContext context) {
  ProgressHud.of(context)?.showAndDismiss(ProgressHudType.error, "load fail");
}

// show progressHud with progress and text
_showProgressHud(BuildContext context) {
  var hud = ProgressHud.of(context);
  hud?.show(ProgressHudType.progress, "loading");

  double current = 0;
  Timer.periodic(Duration(milliseconds: 1000.0 ~/ 60), (timer) {
    current += 1;
    var progress = current / 100;
    hud?.updateProgress(progress, "loading $current%");
    if (progress == 1) {
      // finished
      hud?.showAndDismiss(ProgressHudType.success, "load success");
      timer.cancel();
    }
  });
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ProgressHud(
      // mark hud as global, it should be only one global hud
      isGlobalHud: true,
      child: MaterialApp(
        home: HomePage()
      ),
    );
  }
}

void example() {
    ProgressHud.showLoading();
    ProgressHud.dismiss();
    
    ProgressHud.showAndDismiss(ProgressHudType.success, "load success");
    ProgressHud.showAndDismiss(ProgressHudType.error, "load fail");
    
    ProgressHud.show(ProgressHudType.progress, "loading");
    ProgressHud.updateProgress(progress, "loading 20%");
    
    ProgressHud.showAndDismiss(ProgressHudType.success, "load success");
}