使用 tkinter 的 Python GUI 编程

Question

I have a form which is having multiple rows. By pressing enter it opens up a option window. But every time i hit enter it opens a new option window. How can i control and check if an option window is open then don't open an option window.

import tkinter as tk
from tkinter import ttk
from tkinter import *
from tkinter import messagebox

# Directory/File processing libraries
import os
import configparser
import csv

def callback():
    #messagebox.showinfo("Netezza", Folder_Name_var.get())
    #messagebox.showinfo("Netezza", Table_Name_var.get() )
    config = configparser.ConfigParser()
    config.read('C:\\aa\\config.ini')
    #for value in config['Folder']: print(value)
    for key in config.items('Folder'):
        print (key[1].replace('{Folder_Name}',Folder_Name_var.get()))
        os.makedirs(key[1].replace('{Folder_Name}',Folder_Name_var.get()),exist_ok=True)

def click_tv(event):
    #messagebox.showinfo("Inside")
    selected=trv.focus()
    print(trv.item(selected))

def press_enter(event):
    #messagebox.showinfo("Inside")
    selected=trv.focus()
    print(trv.item(selected))
    print(str((event.keysym)))
    if str((event.keysym))=='Return':
        option_wnd=Toplevel(root)
        option_wnd.geometry('200x200')
        option_wnd.title('Option Window')
        option_wnd.grab_set()
        #option_wnd.pack()
def selection_change(event):
    selected = trv.selection()[0]
    print('You clicked on', trv.item(selected))
    #option_wnd.mainloop()
root = Tk()

Folder_Name_var = tk.StringVar()
Table_Name_var = tk.StringVar()

# This is the section of code which creates the main window
root.geometry('873x498')
root.configure(background='#63B8FF')
root.title('Automation Software - Blue Shield of California')

pic= Canvas(root, height=100, width=100)
#pic= Canvas(root, height=225, width=580)

#picture_file = PhotoImage(file = 'c:\\aa\\bsc.png')
#pic.create_image(0, 0, anchor=NW, image=picture_file)
#pic.place(x=5, y=5)


lbl_Folder_Name = Label(root, text="Folder Name",background='#63B8FF').place(x=600, y=50)
lbl_Table_Name = Label(root, text="Table Name",background='#63B8FF').place(x=600, y=90)

txt_Folder_Name = Entry(root,textvariable = Folder_Name_var).place(x=700, y=50)
txt_Table_Name = Entry(root,textvariable = Table_Name_var).place(x=700, y=90)

Button(root, text="Show", width=10, command=callback).place(x=700,y=120)

tree_frame=Frame(root)
tree_frame.place(x=10,y=260)

tree_scroll=Scrollbar(tree_frame)
tree_scroll.pack(side=RIGHT,fill=Y)

style=ttk.Style()
style.theme_use("default")
style.map("Treeview",background=[('selected','bisque2')],foreground=[('selected','black')])

trv= ttk.Treeview(tree_frame,yscrollcommand=tree_scroll.set, columns=(1,2,3), show="headings", height="10")
trv.heading(1,text="Parameter", anchor=W)
trv.heading(2,text=" Parameter  Description", anchor=W)
trv.heading(3,text=" Specify your value", anchor=W)
trv.tag_configure('even',background="white")
trv.tag_configure('odd',background="steelblue")
trv.bind("<Double-1>",click_tv)
trv.bind("<Return>",press_enter)
trv.bind("<<TreeviewSelect>>",selection_change)
trv.pack()
tree_scroll.config(command=trv.yview)


i=1

with open("c:\\aa\control.txt") as options:
    options_line = csv.reader(options, delimiter='\t')
    for option in options_line:
        #a=1
        if i%2==0:
            trv.insert(parent='', index='end', values=(option), tags=('even',))
            #print("even")
        else:
            trv.insert(parent='', index='end', values=(option), tags=('odd',))
            #print("odd")
        i=i+1
#trv.place(x=100,y=260)


root.mainloop()

Everytime I hit enter on the root window it opens a pop up window. I need to control the it. if the pop up window is open then we should not allow another pop up to open.

Answer 1

The direct way is to use winfo_exists() :

root.option_wnd = None # Init value

def press_enter(event):
    #messagebox.showinfo("Inside")
    selected=trv.focus()
    print(trv.item(selected))
    print(str((event.keysym)))
    if str((event.keysym))=='Return': 
        if root.option_wnd and root.option_wnd.winfo_exists():
            root.option_wnd.lift() # make this window on the top.
        else: # create this window
            root.option_wnd  = tk.Toplevel(root)
            .....

---

But I don't think you need to create this window each time when user type Enter .Create it at the beginning, just show it when user type Enter

For example:

root = tk.Tk()
option_wnd = tk.Toplevel()
option_wnd.wm_protocol("WM_DELETE_WINDOW", option_wnd.withdraw) # when user try to close this window, hide it instead of destroy it
.....


option_wnd.withdraw() # hide this window

def press_enter(event):
    #messagebox.showinfo("Inside")
    selected=trv.focus()
    print(trv.item(selected))
    print(str((event.keysym)))
    if str((event.keysym))=='Return': 
        option_wnd.deiconify() # show it.

Answer 2

If you do not uses classes you could do the following:

options_displayed = False #global

def option_closed(w):
    global options_displayed
    w.destroy() #close the actual window
    options_displayed = False # log the fact it is now close

def press_enter(event):
    global options_displayed # reference global variable
    #messagebox.showinfo("Inside")
    selected=trv.focus()
    print(trv.item(selected))
    print(str((event.keysym)))
    if str((event.keysym))=='Return' and not options_displayed:
        option_wnd=Toplevel(root)
        option_wnd.geometry('200x200')
        option_wnd.title('Option Window')
        option_wnd.grab_set()
        option_wnd.grab_set()
        option_wnd.protocol("WM_DELETE_WINDOW", lambda w= option_wnd :option_closed(w))
        

Answer 3

one option I can think of is binding the option window like this:

option_wnd.bind('<Return>', lambda e: option_wnd.close()) # or withdraw() or quit() ?

binding the option window to when enter is pressed it gets closed (althought I dont know about differences of above functions(there are so you should look up that)) but this can get in the way if you want to enter values using Enter (Return) key because it will close the window. The other option is to bind option window to this event:

option_wnd.bind('<FocusOut>', lambda e: option_wnd.close())

which is when window is not focused on anymore so if you pressed enter it would open a new one still bet the old one should be closed. Also you can try doing some logic programming with sth like when enter is presses 'turn on' a mode when pressing it again wont open window and when you close the existing window it will again allow that.

Answer 4

def press_enter(event):
    #messagebox.showinfo("Inside")
    root.deiconify ()
    selected=trv.focus()
    print(trv.item(selected))
    print(str((event.keysym)))
    if str((event.keysym))=='Return':
        option_wnd=Toplevel(root)
        option_wnd.geometry('200x200')
        option_wnd.title('Option Window')
        option_wnd.grab_set()
        #option_wnd.pack()