Detecting KeyUp events

Question

Is there a way to detect when a key is released, similar to

EventHandler[InputField[], {"KeyDown", "k"} :> Print["k pressed"]]

It seems such detection isn't available at first glance, perhaps it can be achieved some other way?

Alternatively is there a way to detect which keys are currently pressed? I know that;

CurrentValue["ModifierKeys"] 

Works for shift ctrl and such, but I can't seem to figure out how to get a list of regular keys being pressed.

Edit: CurrentValue["EventKey"] does not seem to work for this purpose as It only detects keydown events, thus you cannot do something like the following which detects shift-up

shiftDown = False;
Dynamic[
If[MemberQ[CurrentValue["ModifierKeys"], "Shift"], (shiftDown = True;), 
      If[shiftDown, (shiftDown = False; Print["Shift up code"])]
    ]
]

Mathemtaica.comp.sys- comp.soft-sys.math.mathematica post

Answer 1

To answer the second part of your question, you can use CurrentValue["EventKey"] to get the current key that is being pressed. Modifying your example above:

EventHandler[InputField[], "KeyDown" :> Print[CurrentValue["EventKey"]]]

Answer 2

You can try using NotebookEventActions see the given example in an other subject.

displaying = True;

SetOptions[EvaluationNotebook[], 
 NotebookEventActions :> {{"KeyDown", "k"} :> (If[! displaying, 
      Print["k press"]]), 
   "DownArrowKeyDown" :> (If[! displaying, Print["down press"]]), 
   "MouseClicked" :> (If[displaying, displaying = False])}]

the related thread Make EventHandler work for clicks and keys in a Dynamic display