Loops & Sleeps

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When you call app.go() you start a loop in the GUI that is constantly checking for events - every time it finds an event, it processes it.

But, if an event takes a long time to process, the GUI loop won't be checking for other events - this is when the GUI hangs (stops processing events).

That's why your events need to be quick - they shouldn't have loops or sleeps.

There are a few ways to get around this problem...

Sleeps

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If you want to do something at a later date, you can use the .after() function to specify when it should happen.

• .after(delay_ms, function, *args)
  This will cause the specified function to be executed after the specified number of milliseconds.
  Additional parameters for the function can be specified, by setting *args.
  It will return an ID, which can be used to cancel the function, if it hasn't already started.

• .afterCancel(afterId)
  This will cancel the specified function, if it hasn't already started.

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Infinite Loops

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If you just want something to keep happening forever - maybe updating a statusbar or showing a clock, you can use appJar's built in loop.

Any functions registered in this way, are called at set intervals.

• .registerEvent(function)
  This will cause the GUI to keep repeating the named function in the background.
  By default, the function will repeat every second.

• .setPollTime(time)
  If you want your functions to be called more or less frequently, change the frequency here.

#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)

Conditional Loops

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If you want your loop to only repeat a certain number of times or until a condition is met, you can put a decision at the beginning of the function and still use appJar's built in loop.

You can use this method to simulate both while and for loops.

# global variable to store the count
counter = 10

def countdown():
    global counter
    if counter > 0:
        app.setLabel("counter", str(counter))
        counter -= 1

app.registerEvent(countdown)

Advanced Loops

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If you want more control over your loops, you can simulate your own...

Using the .after() function mentioned above, you can simulate a loop, by having your function call .after() again.

# global variable to store the count
counter = 10

def acceleratingCountdown():
    global counter
    if counter > 0:
        app.setLabel("counter", str(counter))
        counter -= 1
        app.after(100*counter, acceleratingCountdown)

app.after(0, acceleratingCountdown)

This will simulate a countdown, but each time there is a smaller delay between counts.

Long Tasks

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If you want to call a function that does something that takes a long time - such as working with files or networking, you will need a slightly different approach. Have a look at thread support in appJar.