我有一个类MainScreen,它在启动时被实例化。如何从另一个类获取MainScreen对象的字段,而不重新实例化该类?public class MainScreen { public String getUser() { } public void getTheUser() {
MainScreen.this.getUser(); // Here
错误:NameError: name 'mainScreen' is not defined 代码: import tkinter as tkfrommultiprocessing import Process
global mainScreen root = tk.Tk()
mainScreen = tk.Frame