[英]PyQt4_ How to return from MainWindow to LoginWindow?
在以下示例中,如何在按下logOutButton
后关闭MainWindow
并返回LoginWindow
?
import sys
from PyQt4.QtCore import Qt
from PyQt4.QtGui import QDialog, QPushButton, QVBoxLayout, QLineEdit, QMainWindow, QApplication, QMessageBox
class LoginWindow(QDialog):
def __init__(self):
super().__init__()
self.build_UI()
def build_UI(self):
self.username = QLineEdit(self)
self.username.setPlaceholderText("Username: ")
self.password = QLineEdit(self)
self.password.setPlaceholderText("Password: ")
self.password.setEchoMode(QLineEdit.Normal)
self.logInButton = QPushButton("Log In")
self.logInButton.clicked.connect(self.handleLogin)
layout = QVBoxLayout()
layout.addWidget(self.username)
layout.addWidget(self.password)
layout.addWidget(self.logInButton)
self.setLayout(layout)
self.setWindowFlags(Qt.WindowSystemMenuHint)
self.show()
def handleLogin(self):
if self.username.text() == "abc" and self.password.text() == "123": # check credentials
self.accept()
else:
QMessageBox.warning(self, "Error", "Wrong username or password!")
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.logOutButton = QPushButton("Log Out", self)
self.logOutButton.pressed.connect(self.logOut)
self.show()
def logOut(self):
print("log Out")
def run():
app = QApplication(sys.argv)
login = LoginWindow()
if login.exec_() == QDialog.Accepted:
win = MainWindow()
sys.exit(app.exec_())
run()
在这种情况下,您希望主 window 先启动,但在登录期间保持隐藏。 对于注销事件,只需隐藏主 window 并再次显示登录。 我在登录表单中添加了一个退出按钮,以便用户可以退出应用程序。
请注意,我测试的是 Qt5。
class LoginWindow(QDialog):
def __init__(self):
super().__init__()
self.build_UI()
def build_UI(self):
self.username = QLineEdit(self)
self.username.setPlaceholderText("Username: ")
self.password = QLineEdit(self)
self.password.setPlaceholderText("Password: ")
self.password.setEchoMode(QLineEdit.Normal)
self.logInButton = QPushButton("Log In")
self.logInButton.clicked.connect(self.handleLogin)
self.ExitButton = QPushButton("Exit") # add exit button to exit app
self.ExitButton.clicked.connect(self.handleExit)
layout = QVBoxLayout()
layout.addWidget(self.username)
layout.addWidget(self.password)
layout.addWidget(self.logInButton)
layout.addWidget(self.ExitButton)
self.setLayout(layout)
self.setWindowFlags(Qt.WindowSystemMenuHint)
self.show()
def handleLogin(self):
self.accept()
def handleExit(self):
sys.exit() # close app
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.doLogin() # show login button before showing main window
self.logOutButton = QPushButton("Log Out", self)
self.logOutButton.pressed.connect(self.logOut)
self.show()
def logOut(self):
self.hide() # hide main window
self.doLogin() # show login
self.show()
def doLogin(self):
login = LoginWindow()
if login.exec_() != QDialog.Accepted:
self.close() # exit app
def run():
app = QApplication(sys.argv)
win = MainWindow()
sys.exit(app.exec_())
run()
如果要为每次登录重新创建主 window,可以在运行 function 中使用循环。 如果您不想返回登录表单,则需要向主 window 添加退出按钮。
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.logOutButton = QPushButton("Log Out", self)
self.logOutButton.pressed.connect(self.logOut)
self.show()
def logOut(self):
self.close() # goes back to loop
def run():
app = QApplication(sys.argv)
while True: # need exit button to exit app
login = LoginWindow()
login.exec_() # will exit app if no login
win = MainWindow() # recreate main window
app.exec_()
run()
检查登录凭据:
def run():
app = QApplication(sys.argv)
while True: # need exit button to exit app
loginWindow = LoginWindow()
if loginWindow.exec_() == QDialog.Accepted: # user clicked login
usr = loginWindow.username.text()
pwd = loginWindow.password.text()
if usr == "abc" and pwd == "123": # check credentials
win = MainWindow() # recreate main window
app.exec_()
许多解决方案之一(也是最适合我的目的):
import sys
from PyQt4.QtCore import Qt
from PyQt4.QtGui import QDialog, QPushButton, QVBoxLayout, QLineEdit, QMainWindow, QApplication, QMessageBox
class LoginWindow(QDialog):
def __init__(self):
super().__init__()
self.build_UI()
def build_UI(self):
self.username = QLineEdit(self)
self.username.setPlaceholderText("Username: ")
self.password = QLineEdit(self)
self.password.setPlaceholderText("Password: ")
self.password.setEchoMode(QLineEdit.Normal)
self.logInButton = QPushButton("Log In")
self.logInButton.clicked.connect(self.handleLogin)
layout = QVBoxLayout()
layout.addWidget(self.username)
layout.addWidget(self.password)
layout.addWidget(self.logInButton)
self.setLayout(layout)
self.setWindowFlags(Qt.WindowSystemMenuHint)
self.show()
def handleLogin(self):
if self.username.text() == "a" and self.password.text() == "a":
self.accept()
else:
QMessageBox.warning(self, "Error", "Wrong username or password!")
def closeEvent(self, event):
sys.exit()
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.return_to_login = False
self.logOutButton = QPushButton("Log Out", self)
self.logOutButton.pressed.connect(self.logOut)
self.show()
def logOut(self):
self.return_to_login = True
self.close()
def closeEvent(self, event):
if not self.return_to_login:
sys.exit()
def run():
app = QApplication(sys.argv)
while True:
loginWindow = LoginWindow()
if loginWindow.exec_() == QDialog.Accepted:
win = MainWindow()
app.exec_()
run()
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