Things to consider when writing for touch screen?

Question

I'm starting a new project which involves developing an interface for a machine that measures wedge and roundness of lenses and stores the information in a database and reports on it. There's a decent chance we're going to be putting a touch screen on this machine so that it doesn't need to have a mouse or keyboard...

I don't have any experience developing for full size touch screens, so I'm looking for advice/tips/info from you guys...

I can imagine you want to make the elements a little larger than normal... space buttons out a bit more.... things like that... anyone have anything else to add?

Answer 1

If you decide to put in analog controls (scrollbars, rotation widgets, etc) be sure to put in a digital control also. Some companies think that a touch screen means perfect control over something with your fingers. In real life, this translates to minutes of frustration trying to fix a number that's just a little off.

Answer 2

The other obvious one is that there's no equivalent of pointer 'hover'. Not that that affects many apps though.

Answer 3

I wrote my own set of controls for a POS application designed specifically to be touchscreen friendly.

Remember to allow enough real estate for stubby fingers and talons. In our application the users can have these manicures that necessitate them to use the pad of their finger instead of the tip. This means that you need to allow more space for activation areas than you would normally consider in any other type of application.

I would also recommend that you accommodate yourself as a programmer from a testing standpoint and from the point of view that things change and there may need to be a keyboard/mouse attached to a non-touch workstation. I cannot tell you how many times I went to touch my flat panel LCD expecting something to happen, before remembering that I had to use the mouse.

Answer 4

The most obvious thing is that everything on the GUI needs to be big enough for a fingertip to hit, which is sometimes bigger than you think.

As has been mentioned, there's really no way for a right-click action to happen. Also, double-clicking can be tricky with a fingertip on a touch screen.

The other major thing is that you'll want to create a on-screen keyboard that pops up for text entry and an on-screen numpad for number only fields.

Answer 5

The larger gui elements is the major thing. But it applies to all elements, scroll bars, tabs and even text fields.

The other major thing that I can think of, it's hard for the user to right click. So things that require a right click should be avoided, context menus are the only thing that comes to mind at the moment.

Answer 6

Make sure to read your basic UI principles like Fitz law (The time to acquire a target is a function of the distance to and size of the target).

Also consider whether or not the device is stationary or not when it is in use (e.g., like a palmpilot or iphone), research shows that you must accomodate that into your design.