Is a popover that opens from a tab bar good practice in an iOS app?

Question

I have an iPad tab bar app and I want a popover to open when tapping one of the tabs. Is this good practice or should I avoid it?

For example, the bottom tab bar displays the following items:

my books | books | search | about | settings

When tapping 'books' a popover is displayed with book categories:

fiction
non-fiction
fantasy
crime
western

When tapping a category a screen loads a list of books within this category.

I'm asking this question because I personally think this is bad practice. I would like to discourage my client doing this.

Answer 1

Tapping books should bring up a new page. This action is consistent with the behavior of the other tab bars in iOS an would conform with Apple's User Experience Consistency guidelines.

A pop up menu would be used for something like a form input due to the semantic meaning.

Answer 2

If this is meant for both the iPad and the iPhone, you shouldn't be using a popover at all. Popovers are exclusive to the iPad, as it say in Apple's Mobile HIG

Answer 3

Part of the argument against having the popover the way you mention is the potential for confusing hierarchy.

Once you've jumped to, say, non-fiction, I'm guessing you want to support the user viewing/filtering by the different categories, jumping from non-fiction to, say, fiction.

At that point, if those options are accessed through the bottom menu, I think you're working against general convention, where filters are above the content they filter (ex. iPad iTunes App).

One could argue that iOS's bottom tab bar sets a new convention, but I think that can be attributed as an outgrowth of the iPhone's patterns, and not a proposal for a more extended inversion of page hierarchy. I think some of the bottom aligned interactions work well with touch interactions, but it's a balancing act with hierarchy concepts.

I hope that's helpful,

J