2.2 A small lexicon of widgets - Part 2

The next four widgets fall into the non-clickable category. They’re designed to present textual information and don’t have a command property, although you can use bind() to simulate similar behavior.

The Label widget displays some lines of text inside the window:

label = Label(master, option, ...)

The Label widget contains two usable properties, but you need to remember that they are mutually exclusive.

Here you are:

The Label widget has no usable methods – sorry!

The sample in the editor shows how the textvariable accompanied by an observable variable can be used to continuously update the Label’s contents.

import tkinter as tk
 
 
def to_string(x):
    return "Current counter\nvalue is:\n" + str(x)
 
 
def plus():
    global counter
    counter += 1
    text.set(to_string(counter))
 
 
counter = 0
window = tk.Tk()
button = tk.Button(window, text="Go on!", command=plus)
button.pack()
text = tk.StringVar()
label = tk.Label(window, textvariable=text, height=4)
text.set(to_string(counter))
label.pack()
window.mainloop()

The Message widget is very similar to the Label (among other things, it has the same properties) but is able to format the presented text by fitting it automatically to the widget’s size.

message = Message(master, option, ...)

The sample code will tell you more.

import tkinter as tk
 
 
def do_it_again():
    text.set(text.get() + "and again...")
 
 
window = tk.Tk()
button = tk.Button(window, text="Go ahead!", command=do_it_again)
button.pack()
text = tk.StringVar()
message = tk.Message(window, textvariable=text, width=400)
text.set("You did it again... ")
message.pack()
window.mainloop()

Run it and see how the Message widget reacts to the tx variable updates.

The Frame widget is, in fact, a container designed to store other widgets. This means that the Frame can be used to separate a rectangular part of the window and to treat it as a kind of local window. Such a window works as a master widget for all the widgets embedded within it. Moreover, the Frame has its own coordinate system, so when you place a widget inside a Frame, you measure its location relative to the Frame’s upper-left corner, not the window’s one. It also means that if you move the Frame to a new position, all its inner widgets will go with it.

Note: the Frame can grasp virtually any widget – including another Frame.

The Frame has one interesting property:

Take a look at the example in the editor.

import tkinter as tk
 
window = tk.Tk()
 
frame_1 = tk.Frame(window, width=200, height=100, bg='white')
frame_2 = tk.Frame(window, width=200, height=100, bg='yellow')
 
button_1_1 = tk.Button(frame_1, text="Button #1 inside Frame #1")
button_1_2 = tk.Button(frame_1, text="Button #2 inside Frame #1")
button_2_1 = tk.Button(frame_2, text="Button #1 inside Frame #2")
button_2_2 = tk.Button(frame_2, text="Button #2 inside Frame #2")
 
button_1_1.place(x=10, y=10)
button_1_2.place(x=10, y=50)
button_2_1.grid(column=0, row=0)
button_2_2.grid(column=1, row=1)
 
frame_1.pack()
frame_2.pack()
 
window.mainloop()

We’ve defined two separate frames and filled them with two buttons each. Note: we’ve used different geometry managers for both Frames. This is another advantage of the Frame – it helps you arrange the window in the most convenient way.

Pay attention to all four of the Buttons’ constructors – how have we described a master widget there?

The LabelFrame widget is a Frame enriched with a visible border and a title (also visible). The title may be located at one of 12 possible places on the border line.

lfrm = LabelFrame(master, option, ...)

Some of the usable LabelFrame properties are gathered here:

We’ve rebuilt our previous example to employ a LabelFrame instead of a Label – look at the updated code we've provided in the editor.

import tkinter as tk
 
window = tk.Tk()
label_frame_1 = tk.LabelFrame(window, text="Frame #1",
                              width=200, height=100, bg='white')
label_frame_2 = tk.LabelFrame(window, text="Frame #2",
                              labelanchor='se', width=200, height=100, bg='yellow')
 
button_1_1 = tk.Button(label_frame_1, text="Button #1 inside Frame #1")
button_1_2 = tk.Button(label_frame_1, text="Button #2 inside Frame #1")
button_2_1 = tk.Button(label_frame_2, text="Button #1 inside Frame #2")
button_2_2 = tk.Button(label_frame_2, text="Button #2 inside Frame #2")
 
button_1_1.place(x=10, y=10)
button_1_2.place(x=10, y=50)
button_2_1.grid(column=0, row=0)
button_2_2.grid(column=1, row=1)
 
label_frame_1.pack()
label_frame_2.pack()
window.mainloop()

Run it and find the differences.