ghost chars in Tkinter.Entry

[Strider1066]

Is it a bug or a feature?

I'm trying to sub-class an Entry widget that displays a template (i.e. '____-__-__') for users and does keystroke validation. It is starting to work but with one problem. Every key is echoed in the Entry widget. If I were to type a '2', '22__-__-__' is displayed. The next entry replaces the first duplicate with another, that is if I were to then type a '3' the display now shows '233__-__-__', and so on. The correct data is held by the widget as shown by a entry.get() but the display is wrong.

I have started poking at the code with a sharp stick, Please, any suggestions.

steve

from Tkinter import *
import pdb

class entryDate(Entry):
    def __init__(self, parent=None, template="@2###@-##@-##"):
        Entry.__init__(self, parent)
        self.ptr=-1                 # '-1' to accomadate nextwriteable's ptr +=mov
        self.next=object        #for linked list
        self.prior=object       #for linked list
        self.refrList=self.makeReferenceList(template)
        self.workingList=self.makeWorkingList(self.refrList)
        self.bind('<Key>', self.onKeyPress)
        self.config(self, background = "green", width = 10) 
        self.insert(0, (''.join(self.workingList)))
        self.nextWriteable(1)

    def makeReferenceList(self, templateStr):
        ts = templateStr
        tl=[]
        i=0
        while i < len(ts):
            if ts[i]=='@':
                tl.append(ts[i:i+2])
                i += 2
            else:
                tl.append(ts[i : i +1])
                i+=1
        return tl
    
    def makeWorkingList(self, tmplt):
        s=[]
        displayChar = '_'
        for itm in tmplt:
            if itm[0]=='@':
                s.append(itm[1])
            else:
                s.append(displayChar)
        return s

    def onKeyPress(self, event):
        if event.char==event.keysym: #normal key
            self.delete(0, END)
            if self.refrList[self.ptr]=='#': #ie writeable
                if event.char.isdigit():
                    self.workingList[self.ptr]=event.char
                    self.insert(0, (''.join(self.workingList)))
                    self.nextWriteable(1)
                else:                                   # if alpha key
                    s = ''.join(self.workingList)
                    self.insert( 0, (''.join(self.workingList)))
        elif len(event.char)==1:        # punctuation
            pass
        else:
            pass

    def nextWriteable(self, mov):
        self.ptr += mov
        if self.ptr < 0:
            self.ptr=len(self.refList)   #replace with linked list
            self.icursor=self.ptr           # ''
            self.prior.focus_set()
        elif self.ptr == len(self.refrList):
            self.ptr=0                    #replace with linked list
            self.icursor=0                # ''
        elif self.refrList[self.ptr][0]=='@':
            self.nextWriteable(mov)
        else:
            self.icursor(self.ptr)

if __name__=='__main__':
    root = Tk()
    entr= entryDate(root)
    entr.pack()
    entr.focus_set()
    root.mainloop()

[jlm699]

The problem here is that while you have binded the keypress event to your function onKeyPress, it is an instance binding only, Tkinter is still performing its own keypress event at the root level. Remove the binding from your class's __init__ and place it after the line as such:
[code=python]
if __name__=='__ma in__':
root = Tk()
entr= entryDate(root)
root.bind('<Key >',entr.onKeyPr ess)
entr.pack()
entr.focus_set( )
root.mainloop()[/code]

[Strider1066]

Thank you,
That worked like a champ.