单击窗口最大化/最小化按钮时如何自动调整小部件的大小？

如何解决单击窗口最大化/最小化按钮时如何自动调整小部件的大小？

我想根据窗口大小自动调整小部件的大小。

例如：如果窗口大小增加，窗口内的小部件也必须增加。

在哪里可以插入代码？我也可以在 Qt 设计器中编辑吗？

import psycopg2
from PyQt5 import uic,QtWidgets
from PyQt5.QtWidgets import QMessageBox
import sys

try:  # Establishing the connection
    connection = psycopg2.connect(user="postgres",password="admin",host="127.0.0.1",port="5432",dbname="database")
    cursor = connection.cursor()  # create a cursor
    class login(QtWidgets.QMainWindow):
        def __init__(self):  # call the inherited classes
            super(login,self).__init__()
            uic.loadUi('login/login.ui',self)
            self.btnLogin.clicked.connect(self.login)  # login button
            self.btnCancel.clicked.connect(self.cancel)
            self.show()
        def login(self):  # login button
            auser = self.entryUsername.text()  # entry username from postgresql
            apass = self.entryPassword.text()  # entry password from postgresql
            aname = self.entryName.text()  # name from postgresql
            sql_select_admin = """SELECT aid,auser,apass,aname FROM admin WHERE auser = %s and apass = %s """
            cursor.execute(sql_select_admin,(auser,))
            record = cursor.fetchall()
            myid = 0
            self.entryName.setText(" ")
            for row in record:
                myid = row[0]
                self.entryName.setText(row[3])
            if auser == "" and apass == "":  # if username and password are empty
                confirmation = QtWidgets.QMessageBox.warning(self.parent(),"Warning","Please enter Username and Password!",)
                self.entryUsername.setFocus()
            elif auser == "":  # if username is empty
                confirmation = QtWidgets.QMessageBox.warning(self.parent(),"Please enter Username!",)
                self.entryUsername.setFocus()
            elif apass == "":  # if username is empty
                confirmation = QtWidgets.QMessageBox.warning(self.parent(),"Please enter Password!",)
                self.entryPassword.setFocus()
            else:
                if myid == 0:
                    confirmation = QtWidgets.QMessageBox.warning(self.parent(),"Your Username and/or Password was Incorrect!",)
                else:
                    confirmation = QtWidgets.QMessageBox.information(self.parent(),"Information","Your Account is Verified!",)               
        def cancel(self):  # cancel button
            cancelconfirmation = QtWidgets.QMessageBox.question(self.parent(),"Cancel","Are you sure you want to Cancel?",QtWidgets.QMessageBox.Yes,QtWidgets.QMessageBox.No)
            if cancelconfirmation == QMessageBox.Yes:
            self.close()
            sys.exit()
            else:
            return

except (Exception,psycopg2.Error) as error:
    print("Error while connecting to PostgreSQL",error)

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    lw = login()
app.exec_()