tkinter复选框选择影响形状

Question

我正在从一本书开始工作，并且有一个练习，用户从单选按钮中选择一个图形，并通过选择一个复选按钮来指定它是否被填充。在最初看起来像一个简单的练习的日子里奋斗了几天，我完全疲惫不堪。如何使用名为“填充”的复选框来更改矩形和椭圆形的填充？ 任何帮助表示赞赏。

from tkinter import * 

class SelectShapes: 
    def __init__(self): 
     window = Tk() 
     window.title("Select Shapes") 

     self.canvas = Canvas(window, width = 500, height = 400, bg = "white") 
     self.canvas.pack() 

     frame1 = Frame(window) 
     frame1.pack() 

     self.v1 = IntVar() 
     btRectangle = Radiobutton(frame1, text = "Rectangle", variable = self.v1, value = 1, command = self.processRadiobutton) 
     btOval = Radiobutton(frame1, text = "Oval", variable = self.v1, value = 2, command = self.processRadiobutton) 
     btRectangle.grid(row = 2, column = 1) 
     btOval.grid(row = 2, column = 2) 

     self.v2 = IntVar() 
     cbtFill = Checkbutton(frame1, text = "Fill", variable = self.v2, command = self.processCheckbutton) 
     cbtFill.grid(row = 2, column = 3) 


     window.mainloop() 

    def processCheckbutton(self): 
     if self.v2.get() == 1: 
      self.v1["fill"] = "red" 
     else: 
      return False 

    def processRadiobutton(self): 
     if self.v1.get() == 1: 
      self.canvas.delete("rect", "oval") 
      self.canvas.create_rectangle(10, 10, 250, 200, tags = "rect") 
      self.canvas.update() 
     elif self.v1.get() == 2: 
      self.canvas.delete("rect", "oval") 
      self.canvas.create_oval(10, 10, 250, 200, tags = "oval") 
      self.canvas.update() 


SelectShapes() # Create GUI 

Answer 1

问题在于你的processCheckbutton函数。它看起来像是以某种方式将self.v1作为画布对象，但它不是 - 它只是IntVar存储Checkbutton的状态。你需要在那里添加一行改变画布对象的fill属性。要做到这一点，首先需要保存当前画布对象的ID：

在processRadioButton功能：

 self.shapeID = self.canvas.create_rectangle(10, 10, 250, 200, tags = "rect") 
#  ^^^^^^^^^^^^ save the ID of the object you create 

和

 self.shapeID = self.canvas.create_oval(10, 10, 250, 200, tags = "oval") 
#  ^^^^^^^^^^^^ save the ID of the object you create 

终于在processCheckbutton功能：

def processCheckbutton(self): 
    if self.shapeID is not None: 
     if self.v2.get() == 1: 
      self.canvas.itemconfig(self.shapeID, fill="red") 
#         ^^^^^^^^^^^^ use the saved ID to access and modify the canvas object. 
     else: 
      self.canvas.itemconfig(self.shapeID, fill="") 
#              ^^ Change the fill back to transparent if you uncheck the checkbox