Python-将包含tkinter小部件的框架传递给类

Question

I'm tring to build a scrollable GUI window containing ttk.Entry and ttk.Label .

The only way doing so (as noted in many questions here )- is by creating a Canvas , with a frame that contains all that widgets.

So- my goal is to make such class- that gets as a parameter a frame containing all needed widgets, and display it in a window with horizontal and vertical scroll bars ( since I need it in many displays inside my code ).

After coding successfully - I tried to make a class, but it shows only empty green canvas.

Any ideas what am I doing wrong?

import tkinter as tk
from tkinter import ttk


class CanvasWidgets(ttk.Frame):
    def __init__(self, master, frame_in, width=100, height=100):
        ttk.Frame.__init__(self, master)

        self.master = master
        self.frame = frame_in
        self.width, self.height = width, height

        self.build_gui()

    def build_gui(self):
        self.canvas = tk.Canvas(self.master, self.width, self.height, bg='light green')
        # self.frame = ttk.Frame(self.frame_in)

        self.frame.bind("<Configure>", self.onFrameConfigure)
        self.vsb = tk.Scrollbar(self.frame, orient="vertical", command=self.canvas.yview)
        self.hsb = tk.Scrollbar(self.frame, orient="horizontal", command=self.canvas.xview)
        self.canvas.configure(yscrollcommand=self.vsb.set, xscrollcommand=self.hsb.set)
        self.vsb.grid(row=0, column=1, sticky=tk.N + tk.S + tk.W)
        self.hsb.grid(row=1, column=0, sticky=tk.W + tk.N + tk.E)
        self.canvas.create_window((4, 4), window=self.frame, anchor="nw")

        self.canvas.grid(row=0, column=0)

    def onFrameConfigure(self, event):
        self.canvas.configure(scrollregion=self.canvas.bbox("all"))


root = tk.Tk()
frame = ttk.Frame(root)

rows, cols = 5, 5
for row in range(rows):
    for col in range(cols):
        ttk.Label(frame, text=[row, col], relief=tk.SUNKEN, width=5).grid(row=row, column=col, sticky=tk.E)

a = CanvasWidgets(root, frame)
a.grid()
root.mainloop()

Answer 1

The first problem is that you are placing the canvas in master when it needs to be in self . Think of the instance of CanvasWindow as a box in which you are going to put everything else.

The second problem is that, because the frame was created before the canvas, the frame has a lower stacking order than the canvas. You need to call lift on the frame to get it to be above the canvas.

The third problem is that you're putting the scrollbars in frame . You can't put them in the inner frame because they control the inner frame. Instead, they also need to be in self . Both the scrollbar and the canvas need to share a common parent.

The fourth problem is that the frame isn't a child of the canvas, so it won't be clipped by the borders of the canvas. It would be better if the CanvasWidgets created the frame, and then the caller can get the frame and add widgets to it.

For example:

a = CanvasWidgets(root)

rows, cols = 5, 5
for row in range(rows):
    for col in range(cols):
        label = ttk.Label(a.frame, text=[row, col], relief=tk.SUNKEN, width=5)
        label.grid(row=row, column=col, sticky=tk.E)