我正在尝试使用QtNetwork
艰难地检查网络连接,但无法弄清楚如何正确执行此操作。这是我正在处理的代码,似乎既没有调用finished
信号,也没有调用error
信号。我在这里错过了什么?
import sys
from PyQt5 import QtCore, QtNetwork, QtWidgets
class CheckConnectivity:
def __init__(self):
url = QtCore.QUrl("https://www.google.com/")
req = QtNetwork.QNetworkRequest(url)
net_manager = QtNetwork.QNetworkAccessManager()
self.res = net_manager.get(req)
self.res.finished.connect(self.processRes)
self.res.error.connect(self.processErr)
self.msg = QtWidgets.QMessageBox()
def processRes(self):
if self.res.bytesAvailable():
self.msg.information(self, "Info", "You are connected to the Internet.")
else:
self.msg.critical(self, "Info", "You are not connected to the Internet.")
self.msg.show()
self.res.close()
def processErr(self, *args):
print(*args)
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
ic = CheckConnectivity()
sys.exit(app.exec_())
问题
是由于删除net_manager
引起的,请记住,变量仅存在于创建它的上下文中,在您的情况下net_manager
是一个局部变量,将在__init__
方法结束时删除。
class CheckConnectivity(QtCore.QObject):
def __init__(self, *args, **kwargs):
QtCore.QObject.__init__(self, *args, **kwargs)
url = QtCore.QUrl("https://www.google.com/")
req = QtNetwork.QNetworkRequest(url)
self.net_manager = QtNetwork.QNetworkAccessManager()
self.res = self.net_manager.get(req)
self.res.finished.connect(self.processRes)
self.res.error.connect(self.processErr)
self.msg = QtWidgets.QMessageBox()
@QtCore.pyqtSlot()
def processRes(self):
if self.res.bytesAvailable():
self.msg.information(None, "Info", "You are connected to the Internet.")
self.res.deleteLater()
@QtCore.pyqtSlot(QtNetwork.QNetworkReply.NetworkError)
def processErr(self, code):
self.msg.critical(None, "Info", "You are not connected to the Internet.")
print(code)
建议使用 pyqtSlot()
装饰器,因为它的使用有助于应用程序更快一点并消耗更少的内存,但为此,该类必须继承自 QObject
.