python GUI开发: tkinter菜单创建，记事本和画图软件综合项目的实战演练

import tkinter as tk
from tkinter import filedialog, messagebox
 
class SimpleNotepad(tk.Tk):
    def __init__(self):
        super().__init__()
        self.title("Simple Notepad")
        self.filename = None
        self.text_editor = tk.Text(self)
        self.text_editor.pack(expand=True, fill=tk.BOTH)
        self.create_menu()
 
    def create_menu(self):
        menu_bar = tk.Menu(self)
        file_menu = tk.Menu(menu_bar, tearoff=False)
        file_menu.add_command(label="Open", command=self.on_open)
        file_menu.add_command(label="Save", command=self.on_save)
        file_menu.add_separator()
        file_menu.add_command(label="Exit", command=self.on_exit)
        menu_bar.add_cascade(label="File", menu=file_menu)
        self.config(menu=menu_bar)
 
    def on_open(self):
        self.filename = filedialog.askopenfilename(initialdir="./", title="Select a File", filetypes=(("Text Files", "*.txt"), ("All Files", "*.*")))
        if self.filename:
            with open(self.filename, "r") as file:
                self.text_editor.delete("1.0", tk.END)
                self.text_editor.insert(tk.END, file.read())
                self.title(f"{self.filename} - Simple Notepad")
 
    def on_save(self):
        if self.filename:
            with open(self.filename, "w") as file:
                file.write(self.text_editor.get("1.0", tk.END))
        else:
            self.on_save_as()
 
    def on_save_as(self):
        filename = filedialog.asksaveasfilename(initialdir="./", title="Save As", filetypes=(("Text Files", "*.txt"), ("All Files", "*.*")))
        if filename:
            with open(filename, "w") as file:
                file.write(self.text_editor.get("1.0", tk.END))
            self.filename = filename
            self.title(f"{self.filename} - Simple Notepad")
 
    def on_exit(self):
        if messagebox.askokcancel("Quit", "Do you want to quit?"):
            self.destroy()
 
if __name__ == "__main__":
    app = SimpleNotepad()
    app.mainloop()

这段代码实现了一个简单的记事本应用程序，使用了tkinter库来创建GUI界面，并实现了文件的打开、保存和退出功能。代码简洁，注释清晰，是学习GUI编程和文件操作的良好示例。