DART

flutter alertdialog

AlertDialog(
          title: const Text('AlertDialog Title'),
          content: const Text('this is a demo alert diolog'),
          actions: <Widget>[
            TextButton(
              child: const Text('Approve'),
              onPressed: () { 
              	Navigator.of(context).pop();
              },
            ),
          ],
        );

alertdialog flutter

showAlertDialog(BuildContext context) {

  // set up the button
  Widget okButton = FlatButton(
    child: Text("OK"),
    onPressed: () { },
  );

  // set up the AlertDialog
  AlertDialog alert = AlertDialog(
    title: Text("My title"),
    content: Text("This is my message."),
    actions: [
      okButton,
    ],
  );

  // show the dialog
  showDialog(
    context: context,
    builder: (BuildContext context) {
      return alert;
    },
  );
}

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();
          },
        ),
      ],
    );
  },
);

alertdialog shape flutter

  shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.all(Radius.circular(32.0))),

flutter alert dialog shape

shape: CircleBorder(),
shape: RoundedRectangleBorder(),
shape: ContinuousRectangleBorder(),
shape: BeveledRectangleBorder(),