Tkinter标签覆盖：更新还是刷新？

Question

I am building a schedulemaker in Python with a GUI using Tkinter.

I basically have the same problem as in this question : the labels on the schedule table don't get replaced; another one comes on top. But since I dynamically create the table I don't have variable names for the labels.

So can I still update the text value of the label widgets without a variable name? Is there a way with StringVar to do this? Or how do I properly refresh the table?

from tkinter import *

#DATA
class Staff(object):
    def __init__(self, name, ID):
        self.name = name #this data comes from storage
        self.ID = ID #this is for this instance, starting from 0 (for use with grid)

ID42 = Staff("Joe", 0)
ID25 = Staff("George", 1)
ID84 = Staff("Eva", 2)

stafflist = [ID42, ID25, ID84]
weekdays = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]

scheduleDictionary = {}

for r in range(0,3):
    scheduleDictionary[r] = ['shift','shift','shift','shift','shift','shift','shift','shift','shift','shift','shift','shift','shift','shift']

#Build window
root = Tk()

ScheduleFrame = Frame(root)
ScheduleFrame.pack()

#(Re)Build schedule on screen
def BuildSchedule():

    for r in range(1,4):
        Label(ScheduleFrame, text=stafflist[r-1].name).grid(row=r, column=0)

    for c in range(1,15):
        Label(ScheduleFrame, text=weekdays[(c-1)%7]).grid(row=0, column=c)

    for r in range(1,4):
        for c in range(1,15):
            Label(ScheduleFrame, text=scheduleDictionary[r-1][c-1]).grid(row=r, column=c)

#Mouse events
def mouse(event):
    y = event.widget.grid_info()['row'] - 1
    x = event.widget.grid_info()['column'] - 1
    print(x,y)
    shiftSelection(y,x)

#shiftSelection
def shiftSelection(row, column):
    shifts_window = Tk()
    box = Listbox(shifts_window)
    box.insert(1, "MR")
    box.insert(2, "AR")
    box.insert(3, "ER")
    box.pack()
    button = Button(shifts_window, text="Okay", command = lambda: selectShift(shifts_window, box.get(ACTIVE),row, column))
    button.pack()

def selectShift(shifts_window, shift,row, column):
    scheduleDictionary[row][column] = shift
    BuildSchedule()
    shifts_window.destroy()

root.bind("<Button-1>", mouse)

BuildSchedule()

root.mainloop()

Answer 1

The solution is to create the label widgets once, save a reference to each widget, and then change the widget rather than create new widgets.

Since you seem to be building a table-like structure, use a (row,column) tuple to store the widgets in a dictionary. For example:

#(Re)Build schedule on screen
def BuildSchedule():
    global widgets
    widgets = {}

    for r in range(1,4):
        label = Label(ScheduleFrame, text=stafflist[r-1].name)
        label.grid(row=r, column=0)
        widgets[(r,0)] = label

    for c in range(1,15):
        label = Label(ScheduleFrame, text=weekdays[(c-1)%7])
        label.grid(row=0, column=c)
        widgets[(0,c)] = label

    for r in range(1,4):
        for c in range(1,15):
            label = Label(ScheduleFrame, text=scheduleDictionary[r-1][c-1])
            label.grid(row=r, column=c)
            widgets[(r,c)] = label

Later, you can change the label using configure . For example, to change the label for row 1, column 10 you would do:

widgets[(1,10)].configure(text="the new text")

Answer 2

You should always assign a label with a name and if you want to change or update the value of a label use config()

import tkinter
from tkinter import *

#DATA
class Staff(object):
    def __init__(self, name, ID):
        self.name = name #this data comes from storage
        self.ID = ID #this is for this instance, starting from 0 (for use with grid)

ID42 = Staff("Joe", 0)
ID25 = Staff("George", 1)
ID84 = Staff("Eva", 2)

stafflist = [ID42, ID25, ID84]
weekdays = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]

scheduleDictionary = {}

for r in range(0,3):
    scheduleDictionary[r] = ['shift','shift','shift','shift','shift','shift','shift','shift','shift','shift','shift','shift','shift','shift']

#Build window
root = Tk()

ScheduleFrame = Frame(root)
ScheduleFrame.pack()

#(Re)Build schedule on screen
def BuildSchedule():

    for r in range(1,4):
        abcd = tkinter.Label(ScheduleFrame, text=stafflist[r-1].name).grid(row=r, column=0)

    for c in range(1,15):
        efgh = tkinter.Label(ScheduleFrame, text=weekdays[(c-1)%7]).grid(row=0, column=c)

    for r in range(1,4):
        for c in range(1,15):
            ijkl = tkinter.Label(ScheduleFrame, text=scheduleDictionary[r-1][c-1]).grid(row=r, column=c)

Then Use config() or set() if you wish to update the label Minor changes, just naming each variable, you can change it if you want.