How to make the tkinter Treeview row entries icon appear as default?-CodePudding

I have a strange Treeview behaviour that I can't resolve.

I created a widget using a ttk.Frame widget and grid a ttk.Treeview in it as its child. The #0 column shows a directory tree. For each row entry, i.e. tree node, an icon would appear. The option open=True in the .insert() method was used.

When this script is executed, all the icons appear in the Treeview as a default.

However, when this same widget is imported into another script and added into a ttk.PanedWindow widget, the icons in the Treeview does not appear immediately. The icons would only appear when the Treeview row entry is opened by clicking on it. A second click would close the Treeview row entry and the icons would disappear.

I would like the icons in the ttk.Treeview to appear as a default. How do I do this?

CodePudding user response：

I found the cause of this phenomenon. When I customised the style of the ttk.Treeview widget in the other script, I discovered the value of the background option was missing a # symbol. The phenomenon of the ttk.Treeview icon not appearing as a default is caused by an incorrect syntax in the value of the background option.

OS: Linux

Test code reproducing the phenomenon caused by incorrect syntax.

#!/usr/bin/python3
# -*- coding: utf-8 -*-

import tkinter as tk
import tkinter.ttk as ttk


class App(ttk.Frame):

    def __init__(self, parent=None, *args, **kwargs):
        super().__init__(parent)
        self.parent = parent

        # Create Treeview
        self.tree = ttk.Treeview(self, column=('A', 'B'), selectmode='none', height=7)
        self.tree.grid(row=0, column=0, sticky='nsew')

        # Setup column heading
        self.tree.heading('#0', text=' Pic directory', anchor='center')
        self.tree.heading('#1', text=' A', anchor='center')
        self.tree.heading('#2', text=' B', anchor='center')
        # #0, #01, #02 denotes the 0, 1st, 2nd columns

        # Setup column
        self.tree.column('A', anchor='center', width=100)
        self.tree.column('B', anchor='center', width=100)

        # Insert image to #0
        # change to your file path
        self._img = tk.PhotoImage(file="./imagename.png")
        self.tree.insert('', 'end', text="#0's text", image=self._img,
                         value=("A's value", "B's value"))


if __name__ == '__main__':
    # Works
    root = tk.Tk()
    root.geometry('400x180 300 300')
    app = App(root)
    app.grid(row=0, column=0, sticky='nsew')
    root.rowconfigure(0, weight=1)
    root.columnconfigure(0, weight=1)
    root.mainloop()

    # Don't Works - syntax error in value of background causing missing icon
    # in Treeview.
    root = tk.Tk()
    root.geometry('400x180 300 300')
    style = ttk.Style()
    style.configure('Treeview', background='303495')  # should be '#303495'
    app = App(root)
    app.grid(row=0, column=0, sticky='nsew')
    root.rowconfigure(0, weight=1)
    root.columnconfigure(0, weight=1)
    root.mainloop()