Is it bad UX to switch tabs automatically in an iPhone app?

Question

I'm working on an app that allows users to buy tickets for events, one tab will have an event search and a second will provide a way of getting to the basket (there are others in addition to those).

Once someone has added a ticket the most obvious thing is to flip them over to the cart tab where they can pay for their order (I suspect most users won't be buying tickets to more than one event but some might).

But is this bad UX or would it be better for them to stay on the event search tab and add a badge to the cart tab with the number of tickets they've added?

Answer 1

Sudden interactions unless expected are going to confuse your users. I would recommend going with the second approach as it keeps the users informed and also gives them command over what should be their next step.

Also remember that what might seem like as a common and well known interaction pattern to you might not be for your users and hence its best to ensure that they remain in control at all times.

Also if you look at Jacob Nielson's Top-10 Application-Design Mistakes, He has this to say:

Usability suffers when users are dumped directly into an application's guts without any set-up to give them an idea of what's going to happen. Unfortunately, most users won't read a lot of upfront instructions, so you might have to offer them in a short bulleted list or through a single image that lets them grok the application's main point in one view.

Answer 2

You can learn to the APP Store, once someone has touched the button and added the ticket to the basket, the button changes to be “BUY” button, so it is convenient to pay for it.