更改tkinter文本小部件

# import all functions from the tkinter
from tkinter import *
# Create a GUI window  
root = Tk()
# Create a text area box   
# for filling or typing the information.
text = Text(root)
# insert given string in text area
text.insert(INSERT, "Hello, everyone!\n")
text.insert(END, "This is 2020.\n")
text.insert(END, "Pandemic has resulted 
             in economic slowdown worldwide")
text.pack(expand=1, fill=BOTH)
# add tag using indices for the
# part of text to be highlighted
text.tag_add("start", "2.8", "1.13")
#configuring a tag called start
text.tag_config("start", background="black",
                 foreground="red")
# start the GUI
root.mainloop()


# import all functions from the tkinter   
import tkinter as tk
from tkinter.font import Font
# create a Pad class
class Pad(tk.Frame):
    # constructor to add buttons and text to the window
    def __init__(self, parent, *args, **kwargs):
        tk.Frame.__init__(self, parent, *args, **kwargs)
        self.toolbar = tk.Frame(self, bg="#eee")
        self.toolbar.pack(side="top", fill="x")
        # this will add Highlight button in the window
        self.bold_btn = tk.Button(self.toolbar, text="Highlight",
                                  command=self.highlight_text)
        self.bold_btn.pack(side="left")
        # this will add Clear button in the window
        self.clear_btn = tk.Button(self.toolbar, text="Clear",
                                   command=self.clear)
        self.clear_btn.pack(side="left")
        # adding the text 
        self.text = tk.Text(self)
        self.text.insert("end", "Pandemic has resulted in economic slowdown worldwide")
        self.text.focus()
        self.text.pack(fill="both", expand=True)
        #configuring a tag called start
        self.text.tag_configure("start", background="black", foreground="red")
    # method to highlight the selected text
    def highlight_text(self):
        # if no text is selected then tk.TclError exception occurs
        try:
            self.text.tag_add("start", "sel.first", "sel.last")        
        except tk.TclError:
            pass
    # method to clear all contents from text widget.
    def clear(self):
        self.text.tag_remove("start",  "1.0", 'end')
# function
def demo():
    # Create a GUI window 
    root = tk.Tk()
    # place Pad object in the root window
    Pad(root).pack(expand=1, fill="both")
    # start the GUI
    root.mainloop()
# Driver code
if __name__ == "__main__":
    # function calling
    demo()