Question

我的代码：

# -*- coding: utf-8 -*-
"""
Created on Sun Jan 22 14:47:36 2017

@author: Jose Chong
"""
import json
import tkinter

master = tkinter.Tk()
master.title("To-Do List (with saving!)")
master.geometry("300x300")

masterFrame = tkinter.Frame(master)

masterFrame.pack(fill=tkinter.X)

checkboxArea = tkinter.Frame(masterFrame, height=26)

checkboxArea.pack(fill=tkinter.X)

inputStuff = tkinter.Frame(masterFrame)

checkboxList = []

with open('toDoListSaveFile.json') as infile:    
    checkboxList = json.load(infile)

for savedCheckbox in checkboxList:
    n = savedCheckbox
    def destroyCheckbox():
        checkboxRow.destroy()
        del checkboxList[checkboxList.index(str(savedCheckbox))]
    checkboxRow = tkinter.Frame(checkboxArea)
    checkboxRow.pack(fill=tkinter.X)
    checkbox1 = tkinter.Checkbutton(checkboxRow, text = n)
    checkbox1.pack(side=tkinter.LEFT)
    deleteItem = tkinter.Button(checkboxRow, text = "x", command=destroyCheckbox, bg="red", fg="white", activebackground="white", activeforeground="red")
    deleteItem.pack(side=tkinter.RIGHT)

def drawCheckbox():
    newCheckboxInput = entry.get()
    def destroyCheckbox():
        checkboxRow.destroy()
        del checkboxList[checkboxList.index(newCheckboxInput)]
    checkboxList.append(newCheckboxInput)
    entry.delete(0,tkinter.END)
    checkboxRow = tkinter.Frame(checkboxArea)
    checkboxRow.pack(fill=tkinter.X)
    checkbox1 = tkinter.Checkbutton(checkboxRow, text = checkboxList[-1])
    checkbox1.pack(side=tkinter.LEFT)
    deleteItem = tkinter.Button(checkboxRow, text = "x", command=destroyCheckbox, bg="red", fg="white", activebackground="white", activeforeground="red")
    deleteItem.pack(side=tkinter.RIGHT)

def createInputStuff():
    paddingFrame = tkinter.Frame(inputStuff, height=5)
    paddingFrame.pack(fill=tkinter.X)
    buttonDone.pack()
    inputStuff.pack()
    buttonAdd.pack_forget()
    master.bind('<Return>', lambda event: drawCheckbox())

def removeInputStuff():
    inputStuff.pack_forget()
    buttonAdd.pack()
    buttonDone.pack_forget()
    master.unbind('<Return>')


buttonDone = tkinter.Button(inputStuff, text = "Close Input", command=removeInputStuff)


buttonAdd = tkinter.Button(masterFrame, text="Add Item", command=createInputStuff)
buttonAdd.pack()


topInput = tkinter.Frame(inputStuff)
bottomInput = tkinter.Frame(inputStuff)

topInput.pack()
bottomInput.pack()

prompt = tkinter.Label(topInput, text="What do you want your checkbox to be for?")
prompt.pack()
entry = tkinter.Entry(bottomInput, bd=3)
entry.pack(side=tkinter.LEFT)
buttonConfirm = tkinter.Button(bottomInput, text="Confirm", command=drawCheckbox)
buttonConfirm.pack(side=tkinter.LEFT)

master.mainloop()

with open("toDoListSaveFile.json", 'w') as outfile:
    json.dump(checkboxList, outfile)

我的代码的相关位是for savedCheckbox in checkboxList:位（我认为），因此最好在那里阅读，这可能就是问题所在。

问题在于保存文件中加载的复选框，或者更确切地说是删除按钮。新复选框具有删除按钮，可以正常工作，但使用for savedCheckbox in checkboxList:从保存文件加载的按钮具有出现故障的删除按钮。我的意思是：

它们全部删除最后加载的项目（来自保存文件）。因此，如果我的保存文件是四个复选框的列表[＆＃34; f＆＃34;，＆＃34; a＆＃34;，＆＃34; c＆＃34;，＆＃34; e＆＃34;]，加载删除按钮会删除＆＃34; e＆＃34;。如果您点击＆＃34; c＆＃34;旁边的删除按钮，太糟糕了，您就会删除＆＃34; e＆＃34;。如果我在＆＃34; e＆＃34;之后尝试删除任何内容它消失了，它给了我错误＆＃34; ValueError：＆＃39; e＆＃39;不在列表中＃34;。如果最后加载的复选框已被删除，他们也不会销毁checkboxRow，我不确定该复选框的副作用是否未被删除，或者我是否也搞砸了。

如何使删除按钮正常工作并正确删除复选框？正确删除是：

从JSON文件中删除了复选框的数据

复选框所在的整个复选框也应该被移除，选中复选框，复选框旁边的文本以及删除按钮。

对于＆＃34;适当的＆＃34;删除看起来像是看drawCheckbox()，即工作删除框的位置。

Answer 1

这是循环中定义的函数的常见问题。

def destroyCheckbox():
        checkboxRow.destroy()
        del checkboxList[checkboxList.index(str(savedCheckbox))]

destroyCheckbox销毁checkboxRow并从列表中移除savedCheckbox，但在for循环结束时，checkboxRow是最后一行，savedCheckbox是最后一个复选框，所以所有按钮命令都做同样的事情：删除最后一项。

为了解决这个问题，我使用两个参数在for循环外定义了函数destroyCheckbox：savedCheckbox和行。然后我使用lambda和default参数将命令传递给for循环内的按钮（参见How to understand closure in a lambda?）。

def destroyCheckbox(checkbox, row):
    row.destroy()
    checkboxList.remove(str(checkbox))

for savedCheckbox in checkboxList:
    checkboxRow = tkinter.Frame(checkboxArea)
    checkboxRow.pack(fill=tkinter.X)
    checkbox1 = tkinter.Checkbutton(checkboxRow, text=savedCheckbox)
    checkbox1.pack(side=tkinter.LEFT)
    deleteItem = tkinter.Button(checkboxRow, text="x", bg="red", fg="white",
                                activebackground="white", activeforeground="red",
                                command=lambda c=savedCheckbox, r=checkboxRow: destroyCheckbox(c, r))
    deleteItem.pack(side=tkinter.RIGHT)

删除我为待办事项列表中的项目设置的按钮仅删除最后一项，而不是删除已分配的项目

1 个答案: