Simple Dialog (with listview)

Version 1: 

	void _showDialog() {
	showDialog(
	context: context,
	builder: (BuildContext context) {
	// return object of type Dialog
	return AlertDialog(
	title: new Text("Alert Dialog title"),
	content: new Text("Alert Dialog body"),
	actions: <Widget>[
	// usually buttons at the bottom of the dialog
	new FlatButton(
	child: new Text("Close"),
	onPressed: () {
	Navigator.of(context).pop();
	},
	),
	],
	);
	},
	);
	}

Version 2:

Future<void> showListDialog(Function onChange) async {
  int index = await showDialog<int>(
    context: context,
    builder: (BuildContext context) {
      var child = Column(
        children: <Widget>[
          ListTile(title: Text("Please select:")),
          Expanded(
              child: ListView.builder(
                itemCount: 30,
                itemBuilder: (BuildContext context, int index) {
                  return ListTile(
                    title: Text("$index"),
                    onTap: () => Navigator.of(context).pop(index),
                  );
                },
              )),
        ],
      );
      return Dialog(child: child,backgroundColor: Colors.transparent);

    },
  );
  if (index != null) {
    onChange(index);
  }
}

Write your first Flutter app, part 1

https://flutter.dev/docs/get-started/codelab

 flutter channel beta
$ flutter upgrade
$ flutter config --enable-web

You’ll mostly edit lib/main.dart, where the Dart code lives.