Tkinter增量計數器

我正在嘗試使用以下方法逐步減去在按鈕中顯示為文本的數字，但無法將其更新到 4 以下。

def waterclick(watercount = 5):
    water = watercount - 1
    waterlabel.config(text = water)
    print(water)

完整代碼：

# importing whole module
from tkinter import *
from tkinter import ttk
root = Tk()

#name of the program
label = ttk.Label(root, text = '.0.')
label.grid(row = 0, column = 0)
label.config(text = "Howdy Tkinter")
label.config(foreground = 'white', background = 'black', font = ('impact', 14))

#increments water count by -1
def waterclick(watercount = 5):
    water = watercount - 1
    waterlabel.config(text = water)
    print(water)

#water button
waterlabel = ttk.Button(root, text = 5, command = waterclick)
waterlabel.grid(row = 0, column = 1, columnspan = 2)

mainloop()

uj5u.com熱心網友回復：

問題是因為您的函式不會更改watercount函式引數名稱的值。最簡單的解決方法是使用全域變數。這種方法是這樣的：

# importing whole module
from tkinter import *
from tkinter import ttk
root = Tk()

#name of the program
label = ttk.Label(root, text = '.0.')
label.grid(row = 0, column = 0)
label.config(text = "Howdy Tkinter")
label.config(foreground = 'white', background = 'black', font = ('impact', 14))

#increments water count by -1
def waterclick():
    global watercount
    watercount -= 1  # Update value of global variable.
    waterlabel.config(text=watercount)
    print(watercount)

#Define global variable.
watercount = 5

#water button
waterlabel = ttk.Button(root, text = 5, command = waterclick)
waterlabel.grid(row = 0, column = 1, columnspan = 2)

mainloop()

更好的方法是使用 tkinterIntVar類的實體并將其設為Label's textvariable，這樣每次IntVar更改 's 值時標簽都會自動更新。

# importing whole module
from tkinter import *
from tkinter import ttk
root = Tk()

#name of the program
label = ttk.Label(root, text = '.0.')
label.grid(row = 0, column = 0)
label.config(text = "Howdy Tkinter")
label.config(foreground = 'white', background = 'black', font = ('impact', 14))

#increments water count by -1
def waterclick():
    watercount.set(watercount.get()-1)  # Update value of tkinter variable.
    print(watercount.get())

#Define tkinter Variable.
watercount = IntVar(value=5)

#water button
waterlabel = ttk.Button(root, textvariable = watercount, command = waterclick)
waterlabel.grid(row = 0, column = 1, columnspan = 2)

mainloop()

uj5u.com熱心網友回復：

您總是將相同的數字傳遞給您的waterclick函式，因此它總是從 5 中減去 1，因此結果是 4。

解決這個問題的方法是每次呼叫時實際讀取文本中顯示的數字，waterclick然后從該數字中減去它。

要獲取按鈕中顯示的當前數字，您可以使用waterlabel['text']，就像在 Tkinter 中使用任何其他屬性一樣。

你的代碼最終會是這樣的：

#increments water count by -1
def waterclick():
    water = waterlabel['text'] - 1
    waterlabel.config(text = water)
    print(water)

#water button
waterlabel = ttk.Button(root, text = 5, command = waterclick)
waterlabel.grid(row = 0, column = 1, columnspan = 2)

uj5u.com熱心網友回復：

嘗試這個：

# importing whole module
from tkinter import *
from tkinter import ttk
root = Tk()

#name of the program
label = ttk.Label(root, text = '.0.')
label.grid(row = 0, column = 0)
label.config(text = "Howdy Tkinter")
label.config(foreground = 'white', background = 'black', font = ('impact', 14))

#increments water count by -1
def waterclick():
    water = waterlabel.cget("text") - 1
    waterlabel.config(text = water)
    print(water)

#water button
waterlabel = ttk.Button(root, text = 5, command = waterclick)
waterlabel.grid(row = 0, column = 1, columnspan = 2)

mainloop()

標籤：Python 特金特

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