Tkinter 消息框运行两次

Question

I'm making an app which finds the time and Google description of the user's input, and if the input is invalid an error messagebox pops up. However, if I enter a valid input and run it, and then enter an invalid input and try to run it, the messagebox will open up again after I close it. Otherwise it works fine, and I'm not sure what the problem is. Any help would be great, thanks.

import tkinter as tk
from tkinter import *
from tkinter import messagebox
from datetime import datetime
import pytz
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC
from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait


root=tk.Tk()
root.title('Time app')

p_names=['London, Europe','Paris, Europe','Stockholm, Europe','Tokyo, Asia','Arizona, US','Pacific, US','Samoa, Pacific','Galapagos, Pacific','General, Mexico','Mauritius, Indian','Johannesburg, Africa','Barbados, America','Detroit, America','Addis Ababa, Africa','El Salvador, America','Bangkok, Asia']

def place_names():
    p_names.sort()
    li=''
    for pl in p_names:
        li+=pl
        li+='\n'
    return li+'\n'+'+ more'


def value():
    global a
    a = entry_1.get()
    try:
        a.index(',')
        if a.index(' ')<a.index(','):
            a=a.replace(' ','_')
    except:
        a=a
    
    return a


def times():

    try:
        b = a.index(',')
        c = a[b + 2:] + '/' + a[:b]
    
        if c in pytz.all_timezones:
            home = pytz.timezone(c)
            local_time = datetime.now(home)
            current_time = local_time.strftime('%H:%M:%S')
    
            d= a
    
            try:
                e=d.index('_')
                if e<d.index(','):
                    d=d.replace('_',' ')
            except:
                d=a
    
            place_lbl = Label(root, text=d, bg='grey',width=15, font=('bold', 25))
            place_lbl.place(relx=0.33, rely=0.45)
    
            time_lbl = Label(root, text=current_time, bg='grey', font=('bold', 30))
            time_lbl.place(relx=0.41, rely=0.6)
            time_lbl.after(1000,times)
        else:
            messagebox.showerror('Error',"Cannot find '{}'. Please enter in form city, continent (e.g. Arizona, US) or try another location.".format(a))
    except:
        messagebox.showerror('Error',"I Cannot find '{}'. Please enter in form city, continent (e.g. Arizona, US) or try another location.".format(a))
    
    return


def scraped():

    try:
        b = a.index(',')
        c = a[b + 2:] + '/' + a[:b]
    
        if c in pytz.all_timezones:
            PATH = '/Users/BenMcNally/Desktop/chromedriver'
            option = webdriver.ChromeOptions()
            option.add_argument('headless')
            driver = webdriver.Chrome(PATH, options=option)
            driver.implicitly_wait(10)
            driver.get('https://www.google.com/webhp?hl=en&sa=X&ved=0ahUKEwjhj7PUqL_sAhXcURUIHZfmA4oQPAgI')
    
            try:
                search = driver.find_element_by_xpath('//*[@id="tsf"]/div[2]/div[1]/div[1]/div/div[2]/input')
                search.send_keys(a)
                search.send_keys(Keys.RETURN)
    
                desc = WebDriverWait(driver, 10).until(EC.element_to_be_clickable((By.XPATH, '//*[@id="kp-wp-tab-overview"]/div[1]/div/div/div/div[1]')))
    
                side_info_lbl.config(text=desc.text)
            except:
                side_info_lbl.update_idletasks()
                side_info_lbl.config(text='No description available')
    
    
            driver.quit()
    except:
        return


canvas=tk.Canvas(root,height=400,width=700,bg='grey')
canvas.grid()

header_lbl=Label(root,text='Enter a location: ',bg='grey',fg='black',font=('bold',25))
header_lbl.place(relx=0.38,rely=0.1)

entry_1=Entry(root)
entry_1.place(relx=0.37,rely=0.2)

search_btn = Button(root,text='Search',command=lambda:[value(),times(),entry_1.delete(0, 
END),scraped()])
search_btn.place(relx=0.47,rely=0.3)

show_lbl=Label(root,text='Locations',bg='grey',fg='black',font=('bold',20))
show_lbl.place(relx=0.12,rely=0.1)

side_list_lbl=Label(root,text=place_names(),bg='grey',fg='black')
side_list_lbl.place(relx=0.1,rely=0.2)

side_info_lbl = Label(root, text='', wraplength=200, bg='grey', 
fg='black',height=20,width=22)
side_info_lbl.place(relx=0.68, rely=0.1)


root.mainloop()

Answer 1

That's because you called .after firstly.And when you enter a incorrect area, Both of them will raise exception.

So the solution is to stop .after method(use .after_cancel() ) each time you pressed the button:

import tkinter as tk
from tkinter import *
from tkinter import messagebox
from datetime import datetime
import pytz
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC
from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait


root=tk.Tk()
root.title('Time app')

p_names=['London, Europe','Paris, Europe','Stockholm, Europe','Tokyo, Asia','Arizona, US','Pacific, US','Samoa, Pacific','Galapagos, Pacific','General, Mexico','Mauritius, Indian','Johannesburg, Africa','Barbados, America','Detroit, America','Addis Ababa, Africa','El Salvador, America','Bangkok, Asia']

def place_names():
    p_names.sort()
    li=''
    for pl in p_names:
        li+=pl
        li+='\n'
    return li+'\n'+'+ more'


def value():
    global a
    if root.get_time: # if you have run it. root.get_time wouldn't be None
        root.after_cancel(root.get_time) # cancel it
    a = entry_1.get()
    if root.get_time:
        root.after_cancel(root.get_time)
    try:
        a.index(',')
        if a.index(' ')<a.index(','):
            a=a.replace(' ','_')
    except:
        a=a
    return a


def times():
    try:
        b = a.index(',')
        c = a[b + 2:] + '/' + a[:b]

        if c in pytz.all_timezones:
            home = pytz.timezone(c)
            local_time = datetime.now(home)
            current_time = local_time.strftime('%H:%M:%S')

            d= a

            try:
                e=d.index('_')
                if e<d.index(','):
                    d=d.replace('_',' ')
            except:
                d=a

            place_lbl = Label(root, text=d, bg='grey',width=15, font=('bold', 25))
            place_lbl.place(relx=0.33, rely=0.45)

            time_lbl = Label(root, text=current_time, bg='grey', font=('bold', 30))
            time_lbl.place(relx=0.41, rely=0.6)
            root.get_time = root.after(1000, times)
        else:
            messagebox.showerror('Error',"Cannot find '{}'. Please enter in form city, continent (e.g. Arizona, US) or try another location.".format(a))
    except:
        messagebox.showerror('Error',"I Cannot find '{}'. Please enter in form city, continent (e.g. Arizona, US) or try another location.".format(a))

    return


def scraped():
    try:
        b = a.index(',')
        c = a[b + 2:] + '/' + a[:b]

        if c in pytz.all_timezones:
            PATH = '/Users/BenMcNally/Desktop/chromedriver'
            option = webdriver.ChromeOptions()
            option.add_argument('headless')
            driver = webdriver.Chrome(PATH, options=option)
            driver.implicitly_wait(10)
            driver.get('https://www.google.com/webhp?hl=en&sa=X&ved=0ahUKEwjhj7PUqL_sAhXcURUIHZfmA4oQPAgI')

            try:
                search = driver.find_element_by_xpath('//*[@id="tsf"]/div[2]/div[1]/div[1]/div/div[2]/input')
                search.send_keys(a)
                search.send_keys(Keys.RETURN)

                desc = WebDriverWait(driver, 10).until(EC.element_to_be_clickable((By.XPATH, '//*[@id="kp-wp-tab-overview"]/div[1]/div/div/div/div[1]')))

                side_info_lbl.config(text=desc.text)
            except:
                side_info_lbl.update_idletasks()
                side_info_lbl.config(text='No description available')


            driver.quit()
    except:
        return


canvas=tk.Canvas(root,height=400,width=700,bg='grey')
canvas.grid()

header_lbl=Label(root,text='Enter a location: ',bg='grey',fg='black',font=('bold',25))
header_lbl.place(relx=0.38,rely=0.1)

entry_1=Entry(root)
entry_1.place(relx=0.37,rely=0.2)

root.get_time = None # init value
search_btn = Button(root,text='Search',command=lambda: [value(),times(),entry_1.delete(0, END),scraped()])
search_btn.place(relx=0.47,rely=0.3)

show_lbl=Label(root,text='Locations',bg='grey',fg='black',font=('bold',20))
show_lbl.place(relx=0.12,rely=0.1)

side_list_lbl=Label(root,text=place_names(),bg='grey',fg='black')
side_list_lbl.place(relx=0.1,rely=0.2)

side_info_lbl = Label(root, text='', wraplength=200, bg='grey',
fg='black',height=20,width=22)
side_info_lbl.place(relx=0.68, rely=0.1)


root.mainloop()