有没有办法在 tkinter 中将以前的打印覆盖为文本？

Question

There's a simple program that have two text and one button widgets.

The first text widget is for writing codes which will be executed after pressing "run" button. And the second text widget is for using as stdout and stderr.

I have been trying to overwrite the previous print statement with using "\\r". But the result is not as i wish.

The after command is activated after all the processes have done.

What should i do to overwrite the previous print statement, is there a way?

Here are the codes:

#!/usr/bin/env python3
# -*- coding: utf -*-

import sys
import tkinter as tk
import time


class StdIORedirector:
    def __init__(self, text):
        self.text = text

    def write(self, string):
        self.text.insert("end", string)

    def flush(self):
        self.text.update_idletasks()


class App(tk.Frame):
    def __init__(self, master=None):
        tk.Frame.__init__(self, master)
        self.grid(row=0, column=0)

        self.WriteIn = tk.Text(master=self)
        self.WriteIn.grid(row=0, column=0)

        self.StdOut = tk.Text(master=self)
        self.StdOut.grid(row=0, column=2)
        sys.stdout = StdIORedirector(self.StdOut)
        sys.stderr = StdIORedirector(self.StdOut)

        self.RunButton = tk.Button(master=self, text="Run")
        self.RunButton.grid(row=0, column=1)
        self.RunButton.configure(command=self.run)

    def run(self):
        self.StdOut.delete("1.0", "end")
        if "\\r" in self.WriteIn.get("1.0", "end"):
            print("Start")
            self.master.after(1, self.overwrite)
            time.sleep(2)
            print("End")
        exec(self.WriteIn.get("1.0", "end"))

    def overwrite(self):
        self.StdOut.delete("1.0", "end")
        self.master.after(1, self.overwrite)


if __name__ == "__main__":
    root = tk.Tk()
    app = App(master=root)
    app.mainloop()

Answer 1

You can't "overwrite" per se , but you can easily delete existing text using the delete method of the text widget.

For example, to delete the current line that has the cursor you can do:

self.StdOut.delete("insert linestart", "insert lineend")

insert represents the location of the insertion cursor. linestart and lineend are modifiers that adjust the index to be either the start or end of the line, respectively.