Sencha has released an UI design tool Sencha Architect2 that can be used to develop applications in Sencha Touch 2.0 and Ext JS 4.
It comes across as a development environment for Sencha Touch. It provides a drag&drop facility not-only for the UI components, but also for the non-UI components like Controllers, Models, Stores etc.,
It provides code-editing facility where you can write the application logic. This feature can be made a bit more flexible as it still doesn’t allow you to manually edit the main auto-generated code. You can create functions, write the event handling logic in separate placeholders and they are automatically wired up with the main piece of code.
You don’t have to worry about implementing the MVC pattern as it’s automatically taken care. Packaging and deploying the project with the use of the Sencha Touch tools is a breeze.
You can try out the 30-day trial version before taking a call on buying it.