动态生成 Tkinter 按钮

问题描述

我想生成 n 数量的 Tkinter Button 来做不同的事情.我有这个代码:

I want to generate n amount of Tkinter Buttons which do different things. I have this code:

import Tkinter as tk

for i in range(boardWidth):
    newButton = tk.Button(root, text=str(i+1),
                    command=lambda: Board.playColumn(i+1, Board.getCurrentPlayer()))
    Board.boardButtons.append(newButton)

如果 boardWidth 是 5，虽然我得到了标记为 1 到 5 的按钮，但当点击它们时，它们都会执行 Board.playColumn(5、Board.getCurrentPlayer()).

If boardWidth is 5, though I get buttons labelled 1 to 5, when clicked they all do Board.playColumn(5, Board.getCurrentPlayer()).

我需要第一个按钮做Board.playColumn(1, Board.getCurrentPlayer())，第二个按钮做Board.playColumn(2, Board.getCurrentPlayer()) 等等.

I need the first button to do Board.playColumn(1, Board.getCurrentPlayer()), the second to do Board.playColumn(2, Board.getCurrentPlayer()) and so on.

推荐答案

我认为问题在于 lambda 在 i 之后拾取了最终值code>for 循环结束.这应该可以解决这个问题(未经测试):

I think the problem is that the lambda is picking up the final value of i after the for loop ends. This should fix that (untested):

import Tkinter as tk

for i in range(boardWidth):
    newButton = tk.Button(root, text=str(i+1),
                    command=lambda j=i+1: Board.playColumn(j, Board.getCurrentPlayer()))
    Board.boardButtons.append(newButton)

更新

顺便说一句，这是通过向 lambda 函数添加一个参数来实现的，默认值是根据 i 在循环中创建每个函数时的值计算得出的与 i 中的表达式稍后执行时通过闭包返回的最终值相比.

BTW, this worked by adding an argument to the lambda function with a default value calculated from the value of i at the time each one is created in the loop rather than referring back to the final value of i through a closure when the expression within it executes later.

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