说明

本例，在登录界面第一版的基础上，增加了主界面的注销功能和退出功能。

注销功能

    # 动作一：注销
    def on_printAction1_triggered(self):
        self.close()
        dialog = logindialog()
        if  dialog.exec_()==QDialog.Accepted:
            the_window = MainWindow()
            self.windowList.append(the_window)    #这句一定要写，不然无法重新登录
            the_window.show()

退出功能

    # 动作二：退出
    def on_printAction2_triggered(self):
        self.close()

还是很简单的吧，好了，下面给出完整代码。

完整代码

【如下代码，完全复制，直接运行，即可使用】

import sys
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtGui import *
################################################
#######创建主窗口
################################################
class MainWindow(QMainWindow):
    windowList = []
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.setWindowTitle('主界面')
        self.showMaximized()

        # 创建菜单栏
        self.createMenus()

    def createMenus(self):
        # 创建动作 注销
        self.printAction1 = QAction(self.tr("注销"), self)
        self.printAction1.triggered.connect(self.on_printAction1_triggered)

        # 创建动作 退出
        self.printAction2 = QAction(self.tr("退出"), self)
        self.printAction2.triggered.connect(self.on_printAction2_triggered)

        # 创建菜单，添加动作
        self.printMenu = self.menuBar().addMenu(self.tr("注销和退出"))
        self.printMenu.addAction(self.printAction1)
        self.printMenu.addAction(self.printAction2)




    # 动作一：注销
    def on_printAction1_triggered(self):
        self.close()
        dialog = logindialog()
        if  dialog.exec_()==QDialog.Accepted:
            the_window = MainWindow()
            self.windowList.append(the_window)    #这句一定要写，不然无法重新登录
            the_window.show()



    # 动作二：退出
    def on_printAction2_triggered(self):
        self.close()



    # 关闭界面触发事件
    def closeEvent(self, event):
        print(999999999)
        pass


################################################
#######对话框
################################################
class logindialog(QDialog):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.setWindowTitle('登录界面')
        self.resize(200, 200)
        self.setFixedSize(self.width(), self.height())
        self.setWindowFlags(Qt.WindowCloseButtonHint)

        ###### 设置界面控件
        self.frame = QFrame(self)
        self.verticalLayout = QVBoxLayout(self.frame)

        self.lineEdit_account = QLineEdit()
        self.lineEdit_account.setPlaceholderText("请输入账号")
        self.verticalLayout.addWidget(self.lineEdit_account)

        self.lineEdit_password = QLineEdit()
        self.lineEdit_password.setPlaceholderText("请输入密码")
        self.verticalLayout.addWidget(self.lineEdit_password)

        self.pushButton_enter = QPushButton()
        self.pushButton_enter.setText("确定")
        self.verticalLayout.addWidget(self.pushButton_enter)

        self.pushButton_quit = QPushButton()
        self.pushButton_quit.setText("取消")
        self.verticalLayout.addWidget(self.pushButton_quit)

        ###### 绑定按钮事件
        self.pushButton_enter.clicked.connect(self.on_pushButton_enter_clicked)
        self.pushButton_quit.clicked.connect(QCoreApplication.instance().quit)





    def on_pushButton_enter_clicked(self):
        # 账号判断
        if self.lineEdit_account.text() == "":
            return

        # 密码判断
        if self.lineEdit_password.text() == "":
            return

        # 通过验证，关闭对话框并返回1
        self.accept()




################################################
#######程序入门
################################################
if __name__ == "__main__":
    app = QApplication(sys.argv)
    dialog = logindialog()
    if  dialog.exec_()==QDialog.Accepted:
        the_window = MainWindow()
        the_window.show()
        sys.exit(app.exec_())

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