CODE EXAMPLE FOR DART

alertdialogFlutter

showDialog(
  context: context,
  builder: (BuildContext context) {
    return AlertDialog(
      title: new Text("Alert!!"),
      content: new Text("You are awesome!"),
      actions: <Widget>[
        new FlatButton(
          child: new Text("OK"),
          onPressed: () {
            Navigator.of(context).pop();
          },
        ),
      ],
    );
  },
);