Tkinter Python中的双滚动条

Question

我无法让x和y滚动条在使用Python的Tkinter中工作，尽管我已经遵循了多个示例：

1. 如何在python 3.4中使用tkinter添加2个滚动条
2. 在tkinter中添加滚动条到一组小部件
3. 如何在tkinter中制作一个合适的双滚动条框架
4. 垂直和水平滚动条上的Tkinter小部件
5. 水平和垂直滚动画布小部件

滚动条会出现，但当窗口小于框架时不会激活。我怎样才能让它工作（见下图）？

下面是产生我的问题的最小代码（Python 3.7）

import tkinter as tk
from tkinter import ttk

big_font = ("Arial", 50)

class DoubleScrollbarFrame(ttk.Frame):

    def __init__(self,
                 parent,
                 *args,
                 **kwargs):
        self.parent = parent

        super().__init__(self.parent,
                         *args,
                         **kwargs)

        #Set widgets to fill main window such that they are
        #all the same size
        self.columnconfigure(0, weight=1)
        self.rowconfigure(0, weight=1)

        self.create_widgets()
        self.position_widgets()

    def create_widgets(self):
        self.canvas = tk.Canvas(self)
        self.frame = ttk.Frame(self.canvas)
        self.scroll_x = ttk.Scrollbar(self,
                                      orient = tk.HORIZONTAL,
                                      command = self.canvas.xview)
        self.scroll_y = ttk.Scrollbar(self,
                                      orient = tk.VERTICAL,
                                      command = self.canvas.yview)
        self.canvas.config(xscrollcommand = self.scroll_x.set,
                           yscrollcommand = self.scroll_y.set)
        self.canvas.create_window((0,0),
                                  window = self.frame,
                                  anchor = 'nw')
        self.frame.bind('<Configure>',
                        self.set_scrollregion)
        self.sizegrip = ttk.Sizegrip(self)

        #Test
        self.test1 = tk.Label(self.frame,
                              text = 'Test 1',
                              font = big_font)
        self.test2 = tk.Label(self.frame,
                              text = 'Test 2',
                              font = big_font)
        self.test3 = tk.Label(self.frame,
                              text = 'Test 3',
                              font = big_font)

    def position_widgets(self,
                         **kwargs):
        self.test1.grid(row = 0,
                        column = 0,
                        sticky = 'w')
        self.test2.grid(row = 1,
                        column = 0,
                        sticky = 'w')
        self.test3.grid(row = 2,
                        column = 0,
                        sticky = 'w')
        
        self.scroll_x.grid(row = 1,
                           column = 0,
                           sticky = 'ew')

        self.scroll_y.grid(row = 0,
                           column = 1,
                           sticky = 'ns')

        self.canvas.grid(row = 0,
                         column = 0,
                         sticky = 'nsew')
        
        self.frame.grid(row = 0,
                        column = 0,
                        sticky = 'nsew')

        self.sizegrip.grid(row = 1,
                           column = 1,
                           sticky = 'se')

    def set_scrollregion(self,
                         event):
        print('Frame Dimensions: {} x {}'.format(self.frame.winfo_width(),
                                                 self.frame.winfo_height()))
        print('Canvas Dimensions: {} x {}'.format(self.canvas.winfo_width(),
                                                  self.canvas.winfo_height()))
        self.canvas.configure(scrollregion = self.canvas.bbox('all'))

class MainApp(tk.Tk):

    def __init__(self,
                 *args,
                 **kwargs):

        super().__init__(*args,
                         **kwargs)

        #Set widgets to fill main window such that they are
        #all the same size
        self.columnconfigure(0, weight=1)
        self.rowconfigure(0, weight=1)

        self.create_widgets()
        self.position_widgets()

    def create_widgets(self):
        self.frame = DoubleScrollbarFrame(self)

    def position_widgets(self):
        self.frame.grid(row = 0,
                        column = 0,
                        sticky = 'nsew')

    def exit(self):
        self.destroy()

if __name__ == '__main__':

    #Create GUI
    root = MainApp()

    #Run program
    root.mainloop()

Answer 1

问题在于DoubleScrollbarFrame中的这些代码行。定位小部件：

self.frame.grid(row = 0,
                column = 0,
                sticky = 'nsew')

这将从画布中删除对小部件的控制，并将控制权授予网格。它不再是画布对象，因此self。帆布bbox（“all”）正在返回（0,0,1,1）。如果滚动区域设置不正确，滚动条不知道滚动多少。

解决方法很简单：不要在self.frame上调用网格。