解法:
https://stackoverflow.com/questions/61691042/how-can-i-change-tab-with-button-in-tkinter

範例:

Choose a ttk.Notebook instance to use select(tab_id). In your code,Use

Tabs.select(tab2)

要讓輸入的元件focus 設使用 .focus_set():
https://stackoverflow.com/questions/70191953/is-there-a-function-to-switch-tab-and-enter-button-in-tkinter

You can bind the <Return> key event on the Entry widget. Then in the bind callback, get the next widget in the focus order by .tk_focusNext() and move focus to this widget:

import tkinter as tk

root = tk.Tk()

for i in range(10):
    e = tk.Entry(root)
    e.grid(row=0, column=i)
    e.bind('<Return>', lambda e: e.widget.tk_focusNext().focus_set())

root.mainloop()

Combobox has a width attribute which lets you control its size. The width is in terms of the number of characters. So for example, if you know that your combobox entries are single digit numbers, you can set the width attribute as, say 1. Here is an example.

import tkinter as tk
import tkinter.ttk as ttk

root = tk.Tk()
tList = ttk.Combobox(root, values=[1, 2, 3, 4, 5], state="readonly", width=1)
tList.current(0)
tList.grid(row=0, column=1, padx=10, pady=10)
root.mainloop()

解法2: 只調整彈出的視窗
https://stackoverflow.com/questions/39915275/change-width-of-dropdown-listbox-of-a-ttk-combobox

import tkinter as tk
import tkinter.ttk as ttk
import tkinter.font as tkfont

def on_combo_configure(event):
    global fruit
    font = tkfont.nametofont(str(event.widget.cget('font')))
    width = font.measure(fruit[0] + "0") - event.width
    style = ttk.Style()
    style.configure('TCombobox', postoffset=(0,0,width,0))

root = tk.Tk()
root.title("testing the combobox")
root.geometry('300x300+50+50')
fruit = ['apples are the best', 'bananas are better']

c = ttk.Combobox(root, values=fruit, width=10)
c.bind('<Configure>', on_combo_configure)
c.pack()

root.mainloop()

We do this using the event binding as this ensures we can get the actual size of the widget on screen to remove that width from the offset.

import tkinter as tk
from tkinter import filedialog

root = tk.Tk()
root.withdraw()
file_path = filedialog.askopenfilename()
print(file_path)

實用的簡易範例：

import tkinter as tk
from tkinter import ttk
from tkinter import filedialog as fd
from tkinter.messagebox import showinfo

# create the root window
root = tk.Tk()
root.title('Tkinter Open File Dialog')
root.resizable(False, False)
root.geometry('300x150')


def select_file():
    filetypes = (
        ('text files', '*.txt'),
        ('All files', '*.*')
    )

    filename = fd.askopenfilename(
        title='Open a file',
        initialdir='/',
        filetypes=filetypes)

    showinfo(
        title='Selected File',
        message=filename
    )


# open button
open_button = ttk.Button(
    root,
    text='Open a File',
    command=select_file
)

open_button.pack(expand=True)


# run the application
root.mainloop()

多選範例：

import tkinter as tk
from tkinter import ttk
from tkinter import filedialog as fd
from tkinter.messagebox import showinfo

# create the root window
root = tk.Tk()
root.title('Tkinter File Dialog')
root.resizable(False, False)
root.geometry('300x150')


def select_files():
    filetypes = (
        ('text files', '*.txt'),
        ('All files', '*.*')
    )

    filenames = fd.askopenfilenames(
        title='Open files',
        initialdir='/',
        filetypes=filetypes)

    showinfo(
        title='Selected Files',
        message=filenames
    )


# open button
open_button = ttk.Button(
    root,
    text='Open Files',
    command=select_files
)

open_button.pack(expand=True)

root.mainloop()

the askopenfiles() function shows a file dialog and returns file objects of the selected files:

f = fd.askopenfiles()

from tkinter import *
from tkinter.filedialog import asksaveasfile

win= Tk()
win.geometry("750x250")
def save_file():
   f = asksaveasfile(initialfile = 'Untitled.txt',
defaultextension=".txt",filetypes=[("All Files","*.*"),("Text Documents","*.txt")])

btn= Button(win, text= "Save", command= lambda:save_file())
btn.pack(pady=10)

win.mainloop()

使用起來還滿簡單的。

範例2:

from tkinter import *
from tkinter import filedialog
#setting up parent window
root = Tk()

#function definition for opening file dialog
def savef():
    myFile = filedialog.asksaveasfile(mode='w', defaultextension='.txt')
    if myFile is None:
        return
    data = teditor.get(1.0,'end')
    myFile.write(data)
    myFile.close()

說明：asksaveasfile 會取得 file, asksaveasfilename 才是取得 string.

範例3:

from tkinter.filedialog import asksaveasfile
from tkinter import *

base = Tk()

def SaveFile():
   data = [('All tyes(*.*)', '*.*'),("csv file(*.csv)","*.csv")]
   file = asksaveasfilename(filetypes = data, defaultextension = data)
   # file will have file name provided by user.
   # Now we can use this file name to save file.
   with open(file,"w") as f:
      f.write(<data you want to save>)

save_btn = Button(base, text = 'Click to save file ', command = SaveFile)
save_btn.pack(side = TOP, pady = 20,padx = 50)

base.mainloop()

from tkinter import * 
window = Tk() 
window.mainloop()

error message:

macOS 11 or later required

runtime screen:

網傳解法：

This is an issue in the way brew installs Python (source). If you install Python directly via the official installer here then tkinter should work as expected.

重新下載官方的Python，下載用網址：
https://www.python.org/downloads/

會下載檔案：python-3.x.x-macosx1x.x.pkg, 點2下即可開始安裝 python為新的版本。

相關網頁

Interpreter crashes trying to use tkinter library
https://stackoverflow.com/questions/65315077/interpreter-crashes-trying-to-use-tkinter-library

Python Tkinter crashes on macOS 11.1 beta
https://bugs.python.org/issue42480

這題的解法，開新的 thread 就解決了。

如果題目換成，按下按鈕A，中斷一個在其他地方執行的無窮迴圈。
https://stackoverflow.com/questions/27050492/how-do-you-create-a-tkinter-gui-stop-button-to-break-an-infinite-loop

解法1：使用 .after()

You cannot start a while True: loop in the same thread that the Tkinter event loop is operating in. Doing so will block Tkinter’s loop and cause the program to freeze.

For a simple solution, you could use Tk.after to run a process in the background every second or so. Below is a script to demonstrate:

from Tkinter import *

running = True  # Global flag

def scanning():
    if running:  # Only do this if the Stop button has not been clicked
        print "hello"

    # After 1 second, call scanning again (create a recursive loop)
    root.after(1000, scanning)

def start():
    """Enable scanning by setting the global flag to True."""
    global running
    running = True

def stop():
    """Stop scanning by setting the global flag to False."""
    global running
    running = False

root = Tk()
root.title("Title")
root.geometry("500x500")

app = Frame(root)
app.grid()

start = Button(app, text="Start Scan", command=start)
stop = Button(app, text="Stop", command=stop)

start.grid()
stop.grid()

root.after(1000, scanning)  # After 1 second, call scanning
root.mainloop()

Of course, you may want to refactor this code into a class and have running be an attribute of it. Also, if your program becomes anything complex, it would be beneficial to look into Python’s threading module so that your scanning function can be executed in a separate thread.

解法2：global

Here is a different solution, with the following advantages:

1. Does not require manually creating separate threads
2. Does not use Tk.after calls. Instead, the original style of code with a continuous loop is preserved. The main advantage of this is that you do not have to manually specify a number of milliseconds that determines how often your code inside the loop runs, it simply gets to run as often as your hardware allows.

Note: I’ve only tried this with python 3, not with python 2. I suppose the same should work in python 2 too, I just don’t know 100% for sure.

For the UI code and start/stopping logic, I’ll use mostly the same code as in iCodez’ answer. An important difference is that I assume we’ll always have a loop running, but decide within that loop what to do based on which buttons have been pressed recently:

from tkinter import *

running = True  # Global flag
idx = 0  # loop index

def start():
    """Enable scanning by setting the global flag to True."""
    global running
    running = True

def stop():
    """Stop scanning by setting the global flag to False."""
    global running
    running = False

root = Tk()
root.title("Title")
root.geometry("500x500")

app = Frame(root)
app.grid()

start = Button(app, text="Start Scan", command=start)
stop = Button(app, text="Stop", command=stop)

start.grid()
stop.grid()

while True:
    if idx % 500 == 0:
        root.update()

    if running:
        print("hello")
        idx += 1

In this code, we do not call root.mainloop() to have the tkinter GUI continually updating. Instead, we manually update it every so often (in this case, every 500 loop iterations).

Theoretically, this means we may not instantly stop the loop as soon as we hit the Stop button. For example, if at the exact moment where we hit the Stop button, we’re at iteration 501, this code will continue looping until iteration 1000 has been hit. So, the disadvantage of this code is that we have a slighlty less responsive GUI in theory (but it will be unnoticeable if the code within your loop is fast). In return, we get the code inside the loop to run almost as fast as possible (only with sometimes overhead from a GUI update() call), and have it running inside the main thread.

Above sentence make labelText to reference ‘change the value’, but not change depositLabel’s text.

To change depositLabel’s text, use one of following setences:

self.depositLabel['text'] = 'change the value'

OR

self.depositLabel.config(text='change the value')

You can set the state to "readonly"

cb = ttk.Combobox(root, state="readonly", 
                  values=("one", "two", "three"))

From the python 3.6 documentation:

state: One of “normal”, “readonly”, or “disabled”. In the “readonly” state, the value may not be edited directly, and the user can only selection of the values from the dropdown list. In the “normal” state, the text field is directly editable. In the “disabled” state, no interaction is possible.

bind <> to a method…

import tkinter as tk
from tkinter import ttk

class Main(tk.Tk):

  def __init__(self, *args, **kwargs):
    tk.Tk.__init__(self, *args, **kwargs)
    self.container = tk.Frame(self)
    self.container.pack(side="top", fill = "both", expand=True)
    self.container.grid_rowconfigure(0, weight=1)
    self.container.grid_columnconfigure(0, weight=1)
    self.cb=ttk.Combobox(self.container, values=[0,1, 2, 3] , state='readonly')
    self.cb.bind('<<ComboboxSelected>>', self.modified)    
    self.cb.pack()

  def modified (self, event) :
      print(self.cb.get())

main = Main()
main.mainloop()

範例2號：

import tkinter as tk
from tkinter import ttk

def callbackFunc(event):
     print("New Element Selected")
     
app = tk.Tk() 
app.geometry('200x100')

labelTop = tk.Label(app,
                    text = "Choose your favourite month")
labelTop.grid(column=0, row=0)

comboExample = ttk.Combobox(app, 
                            values=[
                                    "January", 
                                    "February",
                                    "March",
                                    "April"])


comboExample.grid(column=0, row=1)
comboExample.current(1)

comboExample.bind("<<ComboboxSelected>>", callbackFunc)


app.mainloop()

範例2號的資料來源：
https://github.com/DelftStack/DelftStack/blob/master/Tutorial/Tkinter/Tkinter%20Combobox_Virtual%20Event%20Binding.py

• W = LEFT,
• E = RIGHT
• N = Center, default 值是 N.

Normally to accomplish what you are after you would simply put sticky = W in the grid options for the Entry widget to left-justify the contents of the cell. However, this will only work for each individual Frame, leaving the contents of each separate LabeledFrame out of alignment.

Easiest way to fix this without changing much code:

You’ll want to add a line to your for loop. If you specify a large minimum-width of the column that self.field’s Frame is inserted into, you can be sure that things will align how you want them to. I’ve also added config options to the grid calls within the LabeledEntry class: sticky = W for the Label & sticky = E for the Entry.

使用 .grid() 可以把元件加入到 layout 裡, 使用 .grid_forget() 可以 hide。

Tkinter: how to show and hide Frame class:

f will be a class, not an instance. Since self.frames is a dictionary with the actual frames being the values, you want to loop over the values:

for f in self.frames.values():
    f.grid_forget()

在套用 UI 時，還有一些參數可以使用，例如：padx、pady

config(**options)
Modifies one or more widget options. If no options are given, the method returns a dictionary containing all current option values.
**options
Widget options.
background=
The background color to use in this frame. This defaults to the application background color. To prevent updates, set the color to an empty string. (the option database name is background, the class is Background)
bg=
Same as background.
borderwidth=
Border width. Defaults to 0 (no border). (borderWidth/BorderWidth)
bd=
Same as borderwidth.
class=
Default is Frame. (class/Class)
colormap=
Some displays support only 256 colors (some use even less). Such displays usually provide a color map to specify which 256 colors to use. This option allows you to specify which color map to use for this frame, and its child widgets. 
By default, a new frame uses the same color map as its parent. Using this option, you can reuse the color map of another window instead (this window must be on the same screen and have the same visual characteristics). You can also use the value “new” to allocate a new color map for this frame. 
You cannot change this option once you’ve created the frame. (colormap/Colormap)
container=
Default is 0. (container/Container)
cursor=
The cursor to show when the mouse pointer is placed over this widget. Default is a system specific arrow cursor. (cursor/Cursor)
height=
Default is 0. (height/Height)
highlightbackground=
Default is system specific. (highlightBackground/HighlightBackground)
highlightcolor=
Default value is system specific. (highlightColor/HighlightColor)
highlightthickness=
Default is 0. (highlightThickness/HighlightThickness)
padx=
Horizontal padding. Default is 0. (padX/Pad)
pady=
Vertical padding. Default is 0. (padY/Pad)
relief=
Border decoration. The default is FLAT. Other possible values are SUNKEN, RAISED, GROOVE, and RIDGE. 
Note that to show the border, you need to change theborderwidth from its default value of 0. (relief/Relief)
takefocus=
If true, the user can use the Tab key to move to this widget. The default value is 0. (takeFocus/TakeFocus)
visual=
No default value. (visual/Visual)
width=
Default value is 0. (width/Width)