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

################################################
#######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_())