PyQt5，用QTcpSocket做的服务端。提示QIODevice::write (Start): device not open

Question

PyQt5，用QTcpSocket做的服务端。提示QIODevice::write (Start): device not open。
开了一个tcp调试助手已确定连接形成。但就是使用write()提示QIODevice::write (Start): device not open。如上图：
连接tcp代码：
class TcpSocket(QTcpSocket):
sinshow = pyqtSignal(str)
def init(self):
super().__init__()
self.tcpServer = QTcpServer(self)
self.abc = QTcpSocket(self)
self.tcpServer.newConnection.connect(self.link)
self.tcpServer.listen(QHostAddress.Any, PORT)#监听ip
def link(self):
self.abc = self.tcpServer.nextPendingConnection()
self.readyRead.connect(self.showMessage)
print('已连接')
def sendMessage(self,message):
print('发送')
print(self.state())
reply = QByteArray()
stream = QDataStream(reply, QIODevice.WriteOnly)
stream.writeUInt16(0)
stream.writeQString(message)
stream.device().seek(0)
stream.writeUInt16(reply.size() - SIZEOF_UINIT16)
self.write(reply)
print(message)

Answer 1

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在您的代码中，有一个错误的地方。当您尝试调用write()方法时，您没有将设备设置为写入模式（即使用stream.writeUInt16(SIZEOF_UINIT16)）。这会导致device not open错误。以下是修复后的代码：

class TcpSocket(QTcpSocket):
    sinshow = pyqtSignal(str)

    def __init__(self):
        super().__init__()
        self.tcpServer = QTcpServer(self)
        self.abc = QTcpSocket(self)
        self.tcpServer.newConnection.connect(self.link)
        self.tcpServer.listen(QHostAddress.Any, PORT)  # 监听IP地址和端口

    def link(self):
        self.abc = self.tcpServer.nextPendingConnection()
        self.readyRead.connect(self.showMessage)
        print('已连接')

    def sendMessage(self, message):
        print('发送')
        print(self.state())
        reply = QByteArray()
        stream = QDataStream(reply, QIODevice.WriteOnly)
        stream.writeUInt16(0)
        stream.writeQString(message)
        stream.device().seek(0)
        stream.writeUInt16(reply.size() - SIZEOF_UINIT16)
        self.write(reply)
        print(message)

在这个修复版本的代码中，我添加了stream.writeUInt16(SIZEOF_UINIT16)以确保设备已经打开并准备好接收数据。现在，当您尝试发送消息时，应该不再出现device not open错误。