Source code for a Sencha Touch 2 native dialog:
Ext.device.Notification.show({
title: 'One Button',
message: 'This is a simple notification with one button.'
});
This example comes from this URL.
This is like an Ext.Msg dialog, but native instead. See http://docs.sencha.com/touch/2.2.1/#!/api/Ext.Msg for more information.