# 文本编辑器

from tkinter import *
import tkinter.messagebox
from tkinter.filedialog import askopenfilename
from tkinter.filedialog import asksaveasfilename


class FileEditor:
    def __init__(self):
        window = Tk()
        window.title("Simple Text Editor")

        menubar = Menu(window)
        window.config(menu=menubar)

        operationMenu = Menu(menubar, tearoff=0)
        menubar.add_cascade(label="File", menu=operationMenu)
        operationMenu.add_command(label="Open", command=self.openFile)
        operationMenu.add_command(label="Save", command=self.saveFile)

        frame0 = Frame(window)
        frame0.grid(row=1, column=1, sticky=W)

        Button(frame0, text="Open", command=self.openFile).grid(row=1, column=1, sticky=W)
        Button(frame0, text="Save", command=self.saveFile).grid(row=1, column=2)

        frame1 = Frame(window)
        frame1.grid(row=2, column=1)

        scrollbar = Scrollbar(frame1)
        scrollbar.pack(side=RIGHT, fill=Y)
        self.text = Text(frame1, width=80, height=40, wrap=WORD, yscrollcommand=scrollbar.set)
        self.text.pack()
        scrollbar.config(command=self.text.yview)

        window.mainloop()

    def openFile(self):
        self.text.delete("1.0", "end")
        try:
            filenameforReading = askopenfilename()
            infile = open(filenameforReading, "r", encoding="utf-8")
            self.text.insert(END, infile.read())
        except UnicodeDecodeError:
            tkinter.messagebox.showerror("error", "打开文件失败！")
        finally:
            infile.close()

    def saveFile(self):
        try:
            filenameforWriting = asksaveasfilename()
            outfile = open(filenameforWriting, "w", encoding="utf-8")
            outfile.write(self.text.get(1.0, END))
        except PermissionError:
            tkinter.messagebox.showerror("error", "保存文件失败！")
        finally:
            outfile.close()


FileEditor()