PyQt5的简单登录界面切换

这个Demo中的界面切换通过PyQt5中按键槽函数响应界面close()，show()函数实现

import sys
from PyQt5.QtWidgets import *
#登录界面类
class  Login (QWidget):
    def __init__(self,parent=None):
        super(Login, self).__init__(parent)
        self.setWindowTitle('登录')
        self.setFixedSize(300,150)
        #全局控件
        allwidget=QWidget(self)
        #allwidget.setFrameStyle(QFrame.Box | QFrame.Raised)
        allwidget.move(50,20)

        #登录界面全局布局
        allayout=QVBoxLayout(allwidget)
        #登录界面局部布局
        login_formlayout=QFormLayout()
        login_hlayout = QHBoxLayout()

        #表单布局控件
        self.account =QLineEdit()
        self.password=QLineEdit()
        self.password.setEchoMode(QLineEdit.Password)
        #水平布局控件
        self.affirm=QPushButton('登录')
        self.affirm.clicked.connect(self.checklogin)
        self.register = QPushButton('注册')
        self.register.clicked.connect(self.putmessage)
        #控件添加到表单布局
        login_formlayout.addRow(QLabel('账号'),self.account)
        login_formlayout.addRow(QLabel('密码'),self.password)

        #控件添加到水平布局
        login_hlayout.addWidget(self.affirm)
        login_hlayout.addWidget(self.register)

        #局部布局添加到全局布局
        allayout.addLayout(login_formlayout)
        allayout.addLayout(login_hlayout)


    #登录响应槽函数
    def checklogin(self):
        #账号信息字典
        account_dict={
     'adc123abc':'123456'}
        account1=self.account.text()
        print(account1)
        password1=self.password.text()
        account_keys=list(account_dict.keys())
        print(account_keys)
        if account1 not in account_keys:
            reply1 = QMessageBox.information(self, '登录出错', '用户不存在',QMessageBox.Yes|QMessageBox.No,QMessageBox.Yes)

        elif password1 == account_dict[account1]:
            login.close()
            demo.show()
        else:
            reply2 = QMessageBox.information(self, '登录出错', '密码错误',QMessageBox.Yes|QMessageBox.No,QMessageBox.Yes)

    #注册响应槽函数
    def putmessage(self):
        reply3 = QMessageBox.information(self, '消息', '暂时未开放注册', QMessageBox.Yes | QMessageBox.No, QMessageBox.Yes)
#主界面
class MenuDemo(QMainWindow):
    def __init__(self, parent=None):
        super(MenuDemo, self).__init__(parent)
        self.setWindowTitle('Demo')
        self.resize(1400, 900)  # 宽×高

if __name__ == '__main__':
    app = QApplication(sys.argv)
    demo = MenuDemo()
    login = Login()
    login.show()

    sys.exit(app.exec_())

运行结果：