Can I change the bottom navigation bar in an iOS app?

Question

I have an application with three tabs on the bottom, as shown, that each bring up their own view within the scope of the 'main' part of the app, BUT, if I want to have separate but similar lists available WITHIN one of the 'events' listed in the main part of the app, is it appropriate to have the bottom bar change to reflect this?

When you are 'in' an event, you can see the people registered for that event, but when you are 'home' you only see people you have 'saved' from within the event lists. I want the bottom bar to change, has this been done successfully before? Is it confusing?

Answer 1

I don't see any problem with this. When you select an item from the list, it is expected that you are navigating to a new view.

It is common for bars to change between views, as what they show should be what makes the most sense for that view, not for the view that came before it.

Of course you should do some user testing, but I don't foresee any problems with this.

Answer 2

Generally speaking, you use a tab bar controller to move from one "root" view to another within the flow of an app. A toolbar on the other hand is used to execute various functionality within a given view. So, it kind of depends on if you are using this as a tab view controller or a toolbar.

For an example (same as the HIG), look at the clock app, which uses a tab bar controller to switch from one root view to the next. And each type of clock has a unique flow.

Examples of toolbars are pretty extensive across all the native iOS apps.

Given the established UX from the native iOS apps, controllers, and the HIG, if you present your events in a modal fashion instead of pushing them onto the navigation controller stack - you could probably get away with "multiple" tab bar setups. I've never seen a tab bar change as a result of a view being pushed onto a navigation controller stack - I have seen the tab bar disappear and be replaced by a different UI component altogether (see the Music app for an example, the list views have a tab bar controller - while the "now playing" has play/pause/volume).

But, honestly, I may not be fully understanding the question or desired outcome. This is what I was able to infer from the wireframes and phrasing.

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http://developer.apple.com/library/ios/#documentation/UserExperience/Conceptual/MobileHIG/Introduction/Introduction.html

Answer 3

You surely can change the bottom bar in YOUR app :) I personally feel it to be a bit awkward if you are changing the bottom menu between 2 views. Usually, in many mobile apps the bottom bar is used as the navigation medium (Pandora, Shazam, Yelp, etc.) and change that only under certain one-off situation (like when playing music). In your situation since I am not familiar with the options and views, I cannot give you a certain answer. But you can look at some of the mobile pattern sites and get a feel of how people generally design the navigations, menus and other UI parts.

Some pattern libraries to get you an idea:

http://www.mobile-patterns.com/custom-navigation

http://inspired-ui.com/