Events


The whole point of GUIs is events!

We want events to be generated whenever the user does something, such as clicking a button, moving a scale, or pressing a key...

We also, sometimes, want events to happen repeatedly...

Make stuff happen...


To make something happen you have to set a function for a widget.
appJar currenly supports four basic use cases:

Breakdown


Be careful it's possible to generate a RuntimeError. If you've got two widgets changing the same variable, say a Scale and a SpinBox, and you want a change in one widget to cause an update in the other, you might inadvertently end up stuck in a recursive loop, until the stack overflows.

In this case, make sure you set the optional parameter callFunction = False when you call the set XXX Function() of a widget.

from appJar import gui

def songChanged(rb):
    print(app.getRadioButton(rb))

def reset(btn):
    # set back to the default, but don't call the change function
    app.setRadioButton("song", "Killer Queen", callFunction=False)

app=gui()
app.addRadioButton("song", "Killer Queen")
app.addRadioButton("song", "Paradise City")
app.setRadioButtonChangeFunction("song", songChanged)
app.addButton("Reset", reset)
app.go()
    from appJar import gui

    def enter(wdgt): 
        print("IN", wdgt)
    def leave(wdgt):
        print("OUT", wdgt)

    app=gui()
    app.addLabel("l1", "Testing...")
    app.setLabelOverFunction("l1", [enter, leave])
    app.go()

Registering Other Event Types

It's possible to register any of the standard event types with appJar widgets

app.getEntryWidget("widget_name").bind("<FocusOut>", function_name, add="+")

Binding Keys

As well as changing widgets, we sometimes want keys to trigger events.
The classic example is the <Return> key, we often want to be able to hit the <Return> key to submit a form...

You may also want to bind other keys to events.

Repeating Events

Sometimes, you want events to keep happening in the background.
GUIs aren't so great at this - if you have a loop in your program, the GUI will hang (stop working until the loop finishes).
Luckily, we have a solution,,,

This is great for updating statuses, checking for messages, etc...

#function to set the status bar
def getLocation():
    x,y,z = mc.player.getPos()
    app.setStatusbar("X: "+ str(round(x,3)), 0)
    app.setStatusbar("Y: "+ str(round(y,3)), 1)
    app.setStatusbar("Z: "+ str(round(z,3)), 2)

# call the getLocation function every second
app.registerEvent(getLocation)

Stopping the GUI

Usually the user just presses the close icon to stop the GUI.
However, you might want to let them do it in other ways - maybe by pressing a button... To stop the GUI, simply call app.stop()

If you want to add a feature to confirm the user really wants to exit, or to save some data, then you'll need a stop function.

def checkStop():
    return app.yesNoBox("Confirm Exit", "Are you sure you want to exit the application?")

app.setStopFunction(checkStop)