如何在 python tkinter mainloop 中定义一个列表而不改变它的值

Question

我试图制作一个 python 使用 PyPDF2 拆分 pdf 的程序。所以我必须定义一个列表来附加元素，但是当循环再次迭代时，列表的值变为空白列表。因此，该程序将制作一个没有任何内容的 pdf。这是我的代码

import tkinter as tk
from PIL import Image, ImageTk
from PyPDF2 import PdfFileReader, PdfFileWriter
from tkinter import filedialog
from tkinter import messagebox
  
elements = []
root7 = tk.Tk()
root7.geometry("600x600")
root7.title("PDF Viewer")
root7.configure(bg="#202020")

    
image7 = Image.open("split.jpg")
new_img7 = image7.resize((600,400))
photo7 = ImageTk.PhotoImage(new_img7)


def open1():
    pdf = filedialog.askopenfilename(initialdir = "/",title = "Select file",filetypes = (("pdf files","*.pdf"),("all files","*.*")))
    elements.append(pdf)

    w = tk.Spinbox(root7, from_=0, to=100, width=3)
    w.place(x=150, y=510)
    elements.append(int(w.get()))

    w1 = tk.Spinbox(root7, from_=0, to=100, width=3)
    w1.place(x=409, y=510)
    elements.append(int(w1.get()))
    
def split():
    pdfs = PdfFileReader(elements[0], "rb")
    pdf_writer = PdfFileWriter()

    for page in range(elements[1], elements[2]):
        pdf_writer.addPage(pdfs.getPage(page))

    output_fname = "splitted.pdf"

    with open(output_fname, 'wb') as out:
        pdf_writer.write(out)

    messagebox.showinfo("Splitted","PDF Saved in Desktop as splitted.pdf")
    

lbl7 = tk.Label(root7,image=photo7)
lbl7.place(x=0, y=0)

button7 = tk.Button(root7, text= 'Open PDF', command=open1, bg="#B8B8B8")
button7.place(width=300, height=50, x=150, y=450)

button8 = tk.Button(root7, text= 'Split PDF', command=split, bg="#B8B8B8")
button8.place(width=300, height=50, x=150, y=540)


root7.update()
root7.mainloop()

有人请帮助。

Answer 1

我终于找到了答案。问题不在于列表，而是在我取spinbox小部件的初始值时引起的，这是修改后的代码。

import tkinter as tk
from PIL import Image, ImageTk
from PyPDF2 import PdfFileReader, PdfFileWriter
from tkinter import filedialog
from tkinter import messagebox
  
w = 0
w1 = 0
root7 = tk.Toplevel()
root7.geometry("600x600")
root7.title("PDF Splitter")
root7.configure(bg="#202020")
elements = []

    
image7 = Image.open("split.jpg")
new_img7 = image7.resize((600,400))
photo7 = ImageTk.PhotoImage(new_img7)


def open1():
    global w, w1
    pdf = filedialog.askopenfilename(initialdir = "/",title = "Select file",filetypes = (("pdf files","*.pdf"),("all files","*.*")))
    elements.append(pdf)

    w = tk.Spinbox(root7, from_=0, to=100, width=3)
    w.place(x=150, y=510)
    

    w1 = tk.Spinbox(root7, from_=0, to=100, width=3)
    w1.place(x=409, y=510)
    elements.append(int(w1.get()))
    
def split():
    global w, w1
    pdfs = PdfFileReader(elements[0], "rb")
    pdf_writer = PdfFileWriter()

    elements.append(int(w.get()))
    elements.append(int(w1.get()))

    w2 = int(w.get())
    w3 = int(w1.get())

    for page in range(45):
        pdf_writer.addPage(pdfs.getPage(w2-1))
        w2+=1
        if (w2-1)==(w3):
            break

    output_fname = "splitted.pdf"

    with open(output_fname, 'wb') as out:
        pdf_writer.write(out)

    messagebox.showinfo("Splitted","PDF Saved in Desktop as splitted.pdf")
    

lbl7 = tk.Label(root7,image=photo7)
lbl7.place(x=0, y=0)

button7 = tk.Button(root7, text= 'Open PDF', command=open1, bg="#B8B8B8")
button7.place(width=300, height=50, x=150, y=450)

button8 = tk.Button(root7, text= 'Split PDF', command=split, bg="#B8B8B8")
button8.place(width=300, height=50, x=150, y=540)


root7.update()
root7.mainloop()

GUI 不是很好，但它仍然有效。

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