Using the designer comes with SMP its very difficult to develop a app with custom screens. But you can write your custom code using the app packaging feature comes with SUP 2.2. You can design the MBOs and generate Hybrid APIs from it, after that you can choose any third party web frameworks to develop the app. An example is here, HWC Application Development using Hybrid API Generation Approach SyBooks OnlineHWC Application Development using Hybrid API Generation Approach
Midhun VP
