python - 如何在 tkinter 中按下按钮时调用函数？

Question

我已经编写了代码，以便当按下“登录”按钮时它会调用“登录”函数。但是，每次我运行代码并按下按钮时，都会显示错误消息“_tkinter.TclError:图像“pyimage2”不存在”，并且我似乎找不到修复我的代码的解决方案。

import tkinter


def Login():
    window = tkinter.Tk()
    window.title("Eat Well")
    window.geometry("295x400")
    UsernameLbl = tkinter.Label(window, text = "Username", fg= "white", bg= "black")
    Utext = tkinter.Entry(window)

    PasswordLbl = tkinter.Label(window, text = "Password", fg = "white", bg= "black")
    Ptext = tkinter.Entry(window, show="*")

    Login = tkinter.Button(window, text = "Login", fg = "black", bg = "honeydew", command = window.destroy  )
    window.configure(background= "#008bb5")
    Photo = tkinter.PhotoImage(file = "Eating.gif")
    w = tkinter.Label(window, image = Photo)




    w.pack()
    UsernameLbl.pack()
    Utext.pack()
    PasswordLbl.pack()
    Ptext.pack()
    Login.pack()
    window.mainloop()

def Mainscreen():
    window = tkinter.Tk()
    window.title("Eat Well")
    window.geometry("295x400")
    Question = tkinter.Label(window, text = "Would you like to create an account or login?", fg = "black", bg = "white")
    Create = tkinter.Button(window, text = "Create an account", fg = "white", bg = "black")
    SignIn = tkinter.Button(window, text =  "Login", fg = "white", bg = "black", command = Login)
    Quit = tkinter.Button(window, text = "Quit", fg = "white", bg = "black", command = window.destroy)
    window.configure(background = "#008bb5")
    Photo = tkinter.PhotoImage(file = "Eating.gif")
    w = tkinter.Label(window, image = Photo)
    w.pack()
    Question.pack()
    Create.pack()
    SignIn.pack()
    Quit.pack()
    window.mainloop()




Mainscreen()

按下“登录”按钮时，应销毁主屏幕并打开“登录”屏幕。但是，目前每当在主屏幕上按下登录按钮时，主屏幕都会保持打开状态，并且登录屏幕将显示为空白屏幕。

Answer 1

这应该有效。注意

的使用

`tkinter.Toplevel()

和Image.open。这是因为调用该函数的按钮本身位于事件窗口中。

import tkinter
from PIL import Image, ImageTk


def Login():
    window = tkinter.Toplevel()
    window.title("Eat Well")
    window.geometry("295x400")
    UsernameLbl = tkinter.Label(window, text = "Username", fg= "white", bg= "black")
    Utext = tkinter.Entry(window)

    PasswordLbl = tkinter.Label(window, text = "Password", fg = "white", bg= "black")
    Ptext = tkinter.Entry(window, show="*")

    Login = tkinter.Button(window, text = "Login", fg = "black", bg = "honeydew", command = window.destroy  )
    window.configure(background= "#008bb5")
    im = Image.open("Eating.gif")
    Photo = ImageTk.PhotoImage(im)
    w = tkinter.Label(window)
    w.pack()
    UsernameLbl.pack()
    Utext.pack()
    PasswordLbl.pack()
    Ptext.pack()
    Login.pack()
    window.mainloop()

def Mainscreen():
    window = tkinter.Tk()
    window.title("Eat Well")
    window.geometry("295x400")
    Question = tkinter.Label(window, text = "Would you like to create an account or login?", fg = "black", bg = "white")
    Create = tkinter.Button(window, text = "Create an account", fg = "white", bg = "black")
    SignIn = tkinter.Button(window, text =  "Login", fg = "white", bg = "black", command = Login)
    Quit = tkinter.Button(window, text = "Quit", fg = "white", bg = "black", command = window.destroy)
    window.configure(background = "#008bb5")
    im = Image.open("Eating.gif")
    Photo = ImageTk.PhotoImage(im)
    w = tkinter.Label(window)
    w.pack()
    Question.pack()
    Create.pack()
    SignIn.pack()
    Quit.pack()
    window.mainloop()