Should the user be able to press disabled buttons on a touch screen?

Question

I'm designing a touchscreen app and there are certain scenarios when the server cannot be reached, a printer is disabled, etc. that will disable a button (like the print button).

My question is: if the button is disabled, should the user be able to select it?

For instance, would it be beneficiary to trigger an overlay with more information as to why the button is disabled when the user selected the disabled button?

Answer 1

To answer your specific question, users should not be able to activate disabled options.

To diverge from UX standards like this is a bad idea - most users would never click the disabled button, and those who did (likely by accident) would be surprised by the result.

They way I would solve this is to display printer status next to the button. Normally, this would read "Printer: Ready" and the button would be enabled, but at other times might display "Printer: Malfunction" next to a disabled button.

Answer 2

I agree with Bevan's answer; you shouldn't depend on the user clicking a disabled button for anything, but to answer your general question, I do think there are circumstances where it's reasonable to provide an on-screen response to tapping on a disabled button:

1. As a user, I generally assume a disabled button implies either that the system requires some additional action on my part or a logical problem (like a disabled "Previous" button on the first page of a paginated view), and so the print button being disabled (at all) is generally in some way my fault/responsibility as the user to rectify. Whether that requires more information or not is highly dependent on the UI design in question.
2. Generally-speaking, touch screen interfaces don't provide the ability to "hover" over a button. In a conventional UI I often use a standard tooltip to explain to the user why a button has been disabled (focusing on the call to action—what the user can do, if anything, to rectify the problem). I don't think it's unreasonable for a "tooltip" workalike to be triggered by tapping a disabled button (although I'd generally present it as a popover nearer to the trigger, as opposed to a dialog box). I do think it's a mistake to depend on the user clicking on the button to uncover the problem, but revealing the issue as a hint contextually is, potentially, appropriate (e.g. "You are on the first page" or "You must select at least one item to print").

The reason I think it's inappropriate in this case is that the cause of the issue (and therefore the action I need to perform to fix it) is confusing.

In terms of answering your specific design problem, you should think first about what the user's call to action is. Is this function entirely optional? If the button wasn't there, would the user be confused? Does the system provide its intended purpose without printing? Is there an alternative course of action I can take if I need a hard copy for some reason? You say "the printer is malfunctioning"—are there humans around I need to advise/notify?

In general the outcome is going to be one of the following:

• Disable the entire kiosk (mark it as "Out of Order" and instruct users to move to another unit, hopefully with a working printer), as I described in this answer to your previous similar question.
• Remove that function altogether, or replace it with a textual indication that Printing is not available from this terminal (this isn't ideal, but if printing forms a very small part of what the product does and your users won't grow to depend on it, then you'll probably be fine).
• If the user can reasonably fix the printer, re-enable the button and then provide a clear call to action instructing the user on how to do so (e.g. "Your document could not be printed because the printer is jammed. Please open the paper drawer and clear any blockages, then press Retry to try again."). This alert could also be something like "This kiosk's printer is currently unavailable. Please alert an attendant to have your document printed", or, at a stretch "Please call IT Helpdesk on 1800 000 000 to report this issue".

Answer 3

Yes and no, but yes. If the button looks disabled as in your example then 'no'. Disabled buttons are disabled, and this convention is seldom violated in most applications. If a button is clearly disabled, users are unlikely to tap it, so the information they are looking for is hidden from them. So, should you be able to click the disabled button to get information, no definitely not, it's not intuitive.

BUT

The information is highly valuable, and should be readily available. Luckily there are other ways of handling it. You could:

• replace the button with text -> "Printer Malfunction" (this brings the information to the top level, no interaction required)
• leave the button in an enabled state (so users know they can tap it) and use the dialog as in your question (leave the information on a second layer, but interaction is intuitive, but the button no longer states its real action)
• when appropriate change the button text to -> "Print Error" (leaves information on a second layer, button represents what it really does)

I don't know which (if any) is appropriate for your interface, but hopefully this will help.