画布tkinter上的删除方法

Question

尝试通过单击创建的“删除矩形”按钮来删除画布上的随机形状。但我的方法似乎不起作用。我不断收到这个错误，一定很小，但我似乎找不到它。

TypeError: removeRects() 缺少 1 个必需的位置参数：'canvas'

from tkinter import *
import random
root = Tk()


class Recta:
    def __init__(self, height=60, width=80):
        self.height = height
        self.width = width
        self.create_buttons()
        self.canvas = Canvas(root)
        self.canvas.pack()

    def removeRects(self,canvas):
        my_rect = self.canvas.create_rectangle(0,0,w,h,fill = "green")
        self.canvas.delete(my_rect)

    def create_buttons(self):
        self.frame = Frame(root, bg='grey', width=400, height=40)
        self.frame.pack(fill='x')
        self.button1 = Button(self.frame, text='Rect', command=self.randomRects)
        self.button1.pack(side='left', padx=10)
        self.button2 = Button(self.frame, text='Remove Rect', command=self.removeRects)
        self.button2.pack(side='left')

    def randomRects(self):
        w = random.randrange(300)
        h = random.randrange(200)
        self.canvas.create_rectangle(0, 0, w, h, fill= "green")


tes = Recta()
root.mainloop()

Answer 1

您必须跟踪您在集合中创建的矩形；然后从集合中提取id 以移除一个矩形。

在这里，我创建了一个列表来聚合创建的矩形的 id：self.canvas.create_rectangle(0, 0, w, h, fill='green') 返回一个存储在集合中的 id 号。

在调用delete 方法时，从最后创建的矩形中检索id（并从集合中删除）并用于remove 来自canvas 的矩形。

import tkinter as tk
import random
root = tk.Tk()

class Recta:

    def __init__(self, height=60, width=80):
        self.height = height
        self.width = width
        self.create_buttons()
        self.canvas = tk.Canvas(root)
        self.canvas.pack()
        self.rects = []

    def create_buttons(self):
        self.frame = tk.Frame(root, bg='grey', width=400, height=40)
        self.frame.pack(fill='x')

        self.button1 = tk.Button(self.frame, text='Add Rect', command=self.randomRects)
        self.button1.pack(side='left', padx=10)
        self.button2 = tk.Button(self.frame, text='Remove Rect', command=self.removeRects)
        self.button2.pack(side='left')

    def removeRects(self):
        if len(self.rects) > 0:
            self.canvas.delete(self.rects.pop())

    def randomRects(self):
        w = random.randrange(300)
        h = random.randrange(200)
        self.rects.append(self.canvas.create_rectangle(0, 0, w, h, fill='green'))


tes = Recta()
root.mainloop()

这是带有 * 导入的相同代码！

from tkinter import *
import random
root = Tk()

class Recta:

    def __init__(self, height=60, width=80):
        self.height = height
        self.width = width
        self.create_buttons()
        self.canvas = Canvas(root)
        self.canvas.pack()
        self.rects = []

    def create_buttons(self):
        self.frame = Frame(root, bg='grey', width=400, height=40)
        self.frame.pack(fill='x')

        self.button1 = Button(self.frame, text='Add Rect', command=self.randomRects)
        self.button1.pack(side='left', padx=10)
        self.button2 = Button(self.frame, text='Remove Rect', command=self.removeRects)
        self.button2.pack(side='left')

    def removeRects(self):
        if len(self.rects) > 0:
            self.canvas.delete(self.rects.pop())

    def randomRects(self):
        w = random.randrange(300)
        h = random.randrange(200)
        self.rects.append(self.canvas.create_rectangle(0, 0, w, h, fill='green'))


tes = Recta()
root.mainloop()