CODEWITHSUNDEEP
pythontkinter
SRC
SRC

Reputation: 590

Way of using root.after() recursively in Tkinter

In Tkinter, I am using root.after() to create thread and update GUI label according to function return value. I want to use same function recursively and update the label according to changing return value of function.

But, it seems thread is calling function only once and terminate. How do I make my thread to call function recursively ? Here is the code which print getData() only twice and terminate.

def recusriveDataFetch( self ):
    self.sched = sched.scheduler(time.time, time.sleep)
    self.sched.enter(100, 2, self.getData(), ()) #create getData() event after every 100 ms
    self.sched.run()

def rootWindow( self ):
    self.root = Tkinter.Tk()
    self.root.title("Hello World")
    self.getData()
    self.root.after( 1000, thread.start_new_thread, self.recusriveDataFetch, () )
    self.root.mainloop()

def getData( self ):
    print " When I will be called multiple times\n "

Any help will be appreciated. Thanks

Upvotes: 0

Views: 4085

Answers (2)

rpcope1
rpcope1

Reputation: 78

Something to note here, is to be very careful how you implement this. Tkinter is not threadsafe, and I've been bitten by this a couple of times. I really love it as far as a GUI toolkit, but you need to keep that in mind. Just make sure nothing inside the thread is interacting with anything in the Tkinter instance.

How I might do this:

def recusriveDataFetch(self):
    self.sched = sched.scheduler(time.time, time.sleep)
    self.sched.enter(100, 2, self.getData(), ()) #create getData() event after every 100 ms
    self.sched.run()

def dataFetchWrapper(self, repeat=True):
    thread.start_new_thread(self.recusriveDataFetch)
    if repeat:  
        self.root.after(100, self.dataFetchWrapper)


def rootWindow(self):
    self.root = Tkinter.Tk()
    self.root.title("Hello World")
    self.getData()
    self.root.after(1000, self.dataFetchWrapper)
    self.root.mainloop()

def getData(self):
    print " When I will be called multiple times\n "

Upvotes: 1

noahbkim
noahbkim

Reputation: 538

Just make the getData function call the root.after method again:

def rootWindow(self):
    self.root = Tkinter.Tk()
    self.root.title("Hello World")
    self.getData()
    self.root.mainloop()

def getData(self):
    print("I will be called multiple times")
    self.root.after(1000, self.getData)

Hope this helps!

Upvotes: 2

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