檢查按鈕值常量

Question

我想通過將1或0（作爲整數）傳遞給此函數來設置checkbutton的值。但是，checkbutton的狀態沒有變化。請幫忙。

def change_On_Off_state(*args): 
     CheckVar1 = IntVar() 
     CheckVar1.set(*args) 
     OnOff = Checkbutton(label2, text = "On", variable = CheckVar1, onvalue = 1, offvalue = 0, height=1, width = 10,anchor = W, bg='Light Blue') 
     OnOff.grid(row = 4, column = 2, padx = 10, sticky = W) 
     #CheckVar1.trace_variable("w", On_Off_state) 

Answer 1

可能的問題是，因爲CheckVar1是局部變量，當你離開的功能它不存在。

使用全局變量，它將工作。

from tkinter import * 

# --- functions --- 

def change_On_Off_state(*args): 
    CheckVar1.set(*args) 
    OnOff = Checkbutton(root, text="On", variable=CheckVar1, onvalue=1, offvalue=0, height=1, width=10, anchor=W, bg='Light Blue') 
    OnOff.grid(row=4, column=2, padx=10, sticky=W) 
    #CheckVar1.trace_variable("w", On_Off_state) 

# --- main ---- 

root = Tk() 

CheckVar1 = IntVar() # global 

change_On_Off_state(1) 

# "start the engine" 
root.mainloop() 

我認爲你不必創建新的Checkbutton()來改變狀態。僅創建Checkbutton和CheckVar一次，並且只使用`CheckVar1.set（...）多次。

from tkinter import * 

# --- functions --- 

def change_On_Off_state(*args): 
    CheckVar1.set(*args) 
    #CheckVar1.trace_variable("w", On_Off_state) 

def change_on_button_press(): 
    if CheckVar1.get() == 1:  
     CheckVar1.set(0) 
    else: 
     CheckVar1.set(1) 

# --- main ---- 

root = Tk() 

# create only once 
CheckVar1 = IntVar() # global 

# create only once 
OnOff = Checkbutton(root, text="On", variable=CheckVar1, onvalue=1, offvalue=0) 
OnOff.grid() 

# use many times 
change_On_Off_state(1) 

# use button to on/off checkbutton 
btn = Button(root, text="On/Off", command=change_on_button_press) 
btn.grid() 

# "start the engine" 
root.mainloop()