Python Tk显示和编辑文件

Question

我正在尝试在Tkinter中编写Python GUI程序。我有基本的模板，但我需要它来打开一个文件，当你点击File > Open。

如何添加这个函数?菜单栏和标签已经在那里了。

#!/usr/bin/python
# -*- coding: utf-8 -*-
from ScrolledText import *
import tkFileDialog
import tkMessageBox
from Tkinter import Tk, Text, BOTH, W, N, E, S, Menu
from ttk import Frame, Button, Label, Style
def main():
    root = Tk()
    root.geometry("350x300+300+300")
    app = Example(root)
    root.mainloop()
class Example(Frame):
    def __init__(self, parent):
        Frame.__init__(self, parent)   
        self.parent = parent
        self.initUI()
    def initUI(self):
        self.parent.title("Grades")
        self.style = Style()
        self.style.theme_use("default")
        self.pack(fill=BOTH, expand=1)
        self.columnconfigure(1, weight=1)
        self.columnconfigure(3, pad=7)
        self.rowconfigure(3, weight=1)
        self.rowconfigure(5, pad=7)
        lbl = Label(self, text="Grades:")
        lbl.grid(sticky=W, pady=4, padx=5)
        lbl = Label(self, text="Averagen Grade:")
        lbl.grid(row=3, column=3, pady=5)
        textPad = ScrolledText(self)
        textPad.grid(row=1, column=0, columnspan=2, rowspan=4, padx=5, sticky=E+W+S+N)
        abtn = Button(self, text="Save",command=save_command )
        abtn.grid(row=1, column=3)
        cbtn = Button(self, text="Close")
        cbtn.grid(row=2, column=3, pady=4)
        hbtn = Button(self, text="Help", command=about_command)
        hbtn.grid(row=5, column=0, padx=5)
        obtn = Button(self, text="OK")
        obtn.grid(row=5, column=3)        
        menubar = Menu(self.parent)
        self.parent.config(menu=menubar)
        fileMenu = Menu(menubar)       
        submenu = Menu(fileMenu)
        submenu.add_command(label="Student")
        submenu.add_command(label="New Student")
        fileMenu.add_cascade(label='Import', menu=submenu, underline=0)
        fileMenu.add_command(label="Open...", command=open_command)
        fileMenu.add_separator()
        fileMenu.add_command(label="Exit", underline=0, command=self.onExit)
        menubar.add_cascade(label="File", underline=0, menu=fileMenu)        

    def onExit(self):
        self.quit()
def about_command():
    label = tkMessageBox.showinfo("About", "Grade keepingn program by Starwarsfan2099")
def save_command(self):
    file = tkFileDialog.asksaveasfile(mode='w')
    if file != None:
    # slice off the last character from get, as an extra return is added
        data = self.textPad.get('1.0', END+'-1c')
        file.write(data)
        file.close()
def open_command():
        file = tkFileDialog.askopenfile(mode='rb',title='Select a file')
        if file != None:
            contents = file.read()
            textPad.insert('1.0',contents)
            file.close()

if __name__ == '__main__':
    main()  

Answer 1

textPad是initUI方法的局部变量，因此在该方法终止后，对该对象的引用将丢失。换句话说，您不能从initUI函数之外访问textPad。

在initUI方法中，更改以下两行:

textPad = ScrolledText(self)
textPad.grid(row=1, column=0, columnspan=2, rowspan=4, padx=5, sticky=E+W+S+N)

to(使textPad成为Example类的字段):

self.textPad = ScrolledText(self)
self.textPad.grid(row=1, column=0, columnspan=2, rowspan=4, padx=5, sticky=E+W+S+N)

我已经改变了你的代码的其他东西，以提高它。具体来说，我已经把那些全局函数的方法变成了Example等类。

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from ScrolledText import *
import tkFileDialog
import tkMessageBox
from Tkinter import Tk, Text, BOTH, W, N, E, S, Menu
from ttk import Frame, Button, Label, Style

class Example(Frame):
    def __init__(self, parent):
        Frame.__init__(self, parent)
        self.parent = parent
        self.initUI()
    def initUI(self):
        self.parent.title("Grades")
        self.style = Style()
        self.style.theme_use("default")
        self.pack(fill=BOTH, expand=1)
        self.columnconfigure(1, weight=1)
        self.columnconfigure(3, pad=7)
        self.rowconfigure(3, weight=1)
        self.rowconfigure(5, pad=7)
        lbl = Label(self, text="Grades:")
        lbl.grid(sticky=W, pady=4, padx=5)
        lbl = Label(self, text="Averagen Grade:")
        lbl.grid(row=3, column=3, pady=5)
        self.textPad = ScrolledText(self)
        self.textPad.grid(row=1, column=0, columnspan=2, rowspan=4, padx=5, sticky=E+W+S+N)
        abtn = Button(self, text="Save",command=self.save_command)
        abtn.grid(row=1, column=3)
        cbtn = Button(self, text="Close", command=self.onExit)
        cbtn.grid(row=2, column=3, pady=4)
        hbtn = Button(self, text="Help", command=self.about_command)
        hbtn.grid(row=5, column=0, padx=5)
        obtn = Button(self, text="OK")
        obtn.grid(row=5, column=3)        
        menubar = Menu(self.parent)
        self.parent.config(menu=menubar)
        fileMenu = Menu(menubar)       
        submenu = Menu(fileMenu)
        submenu.add_command(label="Student")
        submenu.add_command(label="New Student")
        fileMenu.add_cascade(label='Import', menu=submenu, underline=0)
        fileMenu.add_command(label="Open...", command=self.open_command)
        fileMenu.add_separator()
        fileMenu.add_command(label="Exit", underline=0, command=self.onExit)
        menubar.add_cascade(label="File", underline=0, menu=fileMenu)        
    def onExit(self):
        self.parent.destroy()
    def about_command(self):
        label = tkMessageBox.showinfo("About", "Grade keepingn program by Starwarsfan2099")
    def save_command(self):
        file = tkFileDialog.asksaveasfile(mode='w')
        if file != None:
        # slice off the last character from get, as an extra return is added
            data = self.textPad.get('1.0', 'end-1c')
            file.write(data)
            file.close()
    def open_command(self):
            file = tkFileDialog.askopenfile(mode='rb',title='Select a file')
            if file != None:
                contents = file.read()
                self.textPad.insert('1.0', contents)
                file.close()

def main():
    root = Tk()
    root.geometry("350x300+300+300")
    app = Example(root)
    root.mainloop()

if __name__ == '__main__':
    main()  

无论如何，我鼓励你看看这些变化，这样你就会明白你做得不好的地方。老实说，我还没有完全看完，但我所做的改变在我看来是一个进步。