Try to set heading of Treeview to 3-line height. Following code to demo this issue.
import tkinter as tk
from tkinter import ttk
from tkinter.font import Font
root = tk.Tk()
font = ('Courier New', 10)
tkfont = Font(family=font[0], size=font[1])
width, height = tkfont.measure('W'), tkfont.metrics("linespace")
headings = ['A1', 'B1\nB2', 'C1\nC2\nC3']
data = [('A', [1,2,3]), ('B', [2,4,6]), ('C', [3,6,9])]
treeview = ttk.Treeview(root, columns=headings, displaycolumns=headings,
show='tree headings', height=4)
for i, heading in enumerate(headings):
treeview.heading(heading, text=heading)
treeview.column(heading, width=width*4, minwidth=10, anchor=tk.CENTER)
for i, (text, value) in enumerate(data):
treeview.insert('', i, text=text, value=value)
treeview.pack()
#treeview.heading('#0', text='\nHello World\n')
def callback():
treeview.heading('#0', text='\nHello World\n')
button = tk.Button(root, text='Change', command=callback)
button.pack()
root.mainloop()
Case 1, use button Change to call #treeview.heading('#0', text='\nHello World\n'), it doesn't work.
Case 2, remove the # from the line treeview.heading('#0', text='\nHello World\n'), it work.
My question here is
- what's the difference for these two cases, and
- How to refresh the Treeview in case 1 to get same result as in case 2.