问Tkinter增量计数器
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Stack Overflow用户

提问于 2021-10-16 08:44:25

回答 3查看 274关注 0票数 1

我试图让下面的方法增量地减去按钮中显示为文本的数字，但不能让它更新到4以下。

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

完整代码：

# 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()

python

tkinter

回答 3

Stack Overflow用户

回答已采纳

发布于 2021-10-16 08:57:06

问题在于您的函数没有更改watercount的值，它是函数参数的名称。最简单的解决方法是使用全局变量。这种做法是这样的：

# 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()

一种稍微好一些的方法是使用tkinter IntVar类的一个实例，并使其成为Label的textvariable，这样，每当IntVar的值发生变化时，标签就会自动更新。

# 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()

票数 1

Stack Overflow用户

发布于 2021-10-16 08:56:06

您总是将相同的数字传递给您的waterclick函数，因此它总是从5中减去1，因此得到4。

解决这个问题的方法是实际读取每次调用waterclick时在文本中显示的数字，并从该数字中减去它。

要获得按钮中显示的当前数字，您可以使用waterlabel['text']，就像使用Tkinter中的任何其他属性一样。

您的代码将以这样的方式结束：

#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)

票数 0

Stack Overflow用户

发布于 2021-10-16 09:03:23

试试这个：

# 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()