Some quick notes / ramblings about mobile UI.
The standard resources about mobile UI are:
And another important way to approach the topic is to see how other, especially popular applications, are approaching it.
A good approach about user interaction, is the principle of least surprise, ie. do what the the user expects.
I notice a very common pattern in mobile applications, both on Android and iOS, is the bottom icon menu, mostly linking to different states or views of the app. A more hierarchical navigation, history and general menu seems more often to be in a top bar. And of course to keep as much space for content as possible in the middle.
Another UI feature that are common is the collapsed menu button in one of the top corners, – mostly on mobile, but also becoming common on larger devices.
A good approach is also to think about the user action / desired outcome and lead toward that through the interface.
When I think about the core app design, – I want as much screen estate for the content as possible. So at the app I am currently planning, I think the best bet would be to use the entire screen for content, – without any bars etc., but have a single menu button, which can then be used to navigate to different parts/entry-points of the app.
It also makes sense think about the different parts of the app based on what the user want to achieve in that part of the app, and then build the flow through the app leading for the specific outcome.