Tkinter 按钮命令与 Entry 内容获取的正确实践

# 错误示范：函数立即执行
# save_button = tk.Button(root, command=save_key_to_file(), text="Save Key")

# 正确做法：传递函数引用
save_button = tk.Button(root, command=save_key_to_file, text="Save Key")

# 假设 save_key_to_file 需要一个文件名参数
# def save_key_to_file(filename):
#     print(f"Saving key to {filename}")

# 使用 lambda 传递参数
save_button = tk.Button(root, command=lambda: save_key_to_file('custom_file.key'), text="Save Key")

def save_key_to_file():
    key_string = key_entry.get()  # 获取字符串
    print(f"获取到的字符串: {key_string}")

    # 将字符串编码为字节序列（二进制数据）
    key_binary = key_string.encode('utf-8')
    print(f"编码后的二进制数据: {key_binary}")

    try:
        with open("file.key", "wb") as file:
            file.write(key_binary)
        print("密钥已成功保存到 file.key")
    except Exception as e:
        print(f"保存文件时发生错误: {e}")

from tkinter import filedialog
import tkinter as tk
from tkinter import *
from cryptography.fernet import Fernet
import pyperclip
import os

root = Tk()
root.title("Tkinter 密钥管理示例")
root.geometry("500x250")
root.config(bg="#333333") # 设置背景色

key_entry = tk.Entry(root, bg="grey", fg="green", width="50")
key_entry.place(x=35, y=100)

def select_key():
    # 此函数原代码有误，应从文件读取内容并显示在Entry中
    # 修正：打开文件并读取内容，然后更新key_entry
    file_path = filedialog.askopenfilename(defaultextension=".key",
                                           filetypes=[("Key Files", "*.key"), ("All Files", "*.*")])
    if file_path:
        try:
            with open(file_path, "rb") as file:
                key_data = file.read()
                key_entry.delete(0, "end")
                # 假设密钥是UTF-8可解码的，否则可能需要其他处理
                key_entry.insert(0, key_data.decode('utf-8'))
            print(f"密钥已从 {file_path} 加载。")
        except Exception as e:
            print(f"加载密钥时发生错误: {e}")

def generate_key():
    key = Fernet.generate_key() # key 是 bytes 类型
    key_entry.delete(0, "end")
    key_entry.insert(0, key.decode('utf-8')) # 将 bytes 解码为 str 以便在 Entry 中显示
    print("新密钥已生成并显示。")

def save_key_to_file():
    key_string = key_entry.get()
    if not key_string:
        print("Entry 中没有内容可保存。")
        return

    # 将字符串编码回 bytes 类型，以便写入二进制文件
    key_binary = key_string.encode('utf-8') 

    try:
        # 使用 filedialog 让用户选择保存路径
        file_path = filedialog.asksaveasfilename(defaultextension=".key",
                                                 filetypes=[("Key Files", "*.key"), ("All Files", "*.*")])
        if file_path:
            with open(file_path, "wb") as file:
                file.write(key_binary)
            print(f"密钥已成功保存到 {file_path}")
    except Exception as e:
        print(f"保存文件时发生错误: {e}")


# 按钮定义及命令绑定
# 注意：command 参数直接传递函数引用，不带括号
load_button = tk.Button(root, text="Load Key", command=select_key, 
                        state="normal", borderwidth=0, bg="black", fg="green", 
                        activebackground='#2e2e2e', activeforeground="green")
load_button.place(x=359, y=130)

save_button = tk.Button(root, text="Save Key", command=save_key_to_file, 
                        state="normal", borderwidth=0, bg="black", fg="green", 
                        activebackground='#2e2e2e', activeforeground="green")
save_button.place(x=270, y=130)

generate_button = tk.Button(root, text="Generate key", command=generate_key, 
                           borderwidth=0, bg="black", fg="green", 
                           activebackground='#2e2e2e', activeforeground="green")
generate_button.place(x=35, y=130)

root.mainloop()