LV with touch screen

[CoastalMaineBird]

I'm an old hand at LabVIEW but have never used it on Touch Screens. 

I have a potential client who already has a computer with Touch Screen (I haven't seen it yet - I don't know what brand).

Two questions (OK, maybe more):

1... What gotchas have you run into?  I know there has to be a pop-up keyboard and possibly a pop-up numerical keyboard. Do they work sensibly? Are they NI products or third party? Can you use sliders / knobs for rough settings?  What else works differently from desktop UI?

2... Any advantages of LV2022 over LV2018 with touch screens?

[RTSLVU]

We use ELO touch screens in our ATE systems. The touch screen basically acts like a mouse.

The cursor follows your finger and screen presses register as left mouse button clicks.

So there is nothing special I have to do in LabVIEW, except make sure any buttons are large enough on the screen to be easily pressed 

[LLindenbauer]

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@CoastalMaineBird wrote:

1... What gotchas have you run into?  I know there has to be a pop-up keyboard and possibly a pop-up numerical keyboard. Do they work sensibly? Are they NI products or third party? Can you use sliders / knobs for rough settings?  What else works differently from desktop UI?

Gotcha: Hardware/Calibration Issues with the touch surface itself, where the sensor sometimes registers a mouse-up/mouse-down sequence when holding or dragging. This can make everything connected to holding down the mouse unreliable or unusable. Avoid dragging and holding.

Virtual keyboards are actually not that difficult to do oneself (just a bit tedious) and there are a few of them in the package managers. You may even be able to call up the OS's own virtual keyboard or hook into some other external tool. It depends a bit on the screen space you have available. Small screens and nonstandard layouts will probably require at least some hand-tuning.

General Points:

• The user can't see what's under the finger.
• Mistakes happen more frequently, try to limit their damage.
• Image wearing gloves or using your thumb.
• On some screens, the edges can't be touched.

[rolfk]

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@LLindenbauer wrote:

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@CoastalMaineBird wrote:

1... What gotchas have you run into?  I know there has to be a pop-up keyboard and possibly a pop-up numerical keyboard. Do they work sensibly? Are they NI products or third party? Can you use sliders / knobs for rough settings?  What else works differently from desktop UI?

General Points:

• The user can't see what's under the finger.
• Mistakes happen more frequently, try to limit their damage.
• Image wearing gloves or using your thumb.
• On some screens, the edges can't be touched.

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• Don't use right click menus! You don't have a right click mouse button. There is however a neat trick shown at the recent GDevCon in Amsterdam where you place an actual button on top of the object whose context menu you want to show. In the mouse down filter event you hide the control and modify the event to indicate that button 2 was pressed, and LabVIEW reinterprets that button click as a right click event and since the button is not visible anymore, it applies it to the underlaying control element, causing its popup menu to appear. In the menu handling event you do what you need to do and make the button again visible.

[Bob_Schor]

When Dell made their early "All-in-Ones", a TouchScreen with a handle into which you plugged a Keyboard, a student I was advising bought one for a LabVIEW Project.  Wow, getting that to work was a nightmare!  Fortunately, he graduated ...  I don't remember the hoops I needed to jump through to get screen taps to be mouse clicks, and, yes, right clicks were a real problem (I think if you held your finger down for a second, it became a Right Click, but the only problem was LabVIEW was supposed to be providing a "Behavioral Task" -- when a Target appears on the (Touch) Screen, touch it as quickly as you can if it is Green, but not if it is Red (or turns Red as you start to reach).

Bob Schor