pyqt5 单例模式

在PyQt5中实现单例模式可以通过以下步骤：

1. 导入必要的模块：

from PyQt5.QtWidgets import QApplication
from PyQt5.QtCore import QCoreApplication
from PyQt5.QtGui import QIcon
from PyQt5.QtWidgets import QSystemTrayIcon

2. 创建一个继承自QApplication的子类，并在该子类中实现单例模式：

class SingleApplication(QApplication):
    def __init__(self, argv, app_id):
        super().__init__(argv)
        self.setApplicationName(app_id)
        self.setQuitOnLastWindowClosed(False)
        self.tray_icon = QSystemTrayIcon(QIcon("icon.png"), self)
        self.tray_icon.show()
        self.tray_icon.setToolTip(app_id)
        self.tray_icon.activated.connect(self.handle_tray_icon_activated)
        self.instance = QSingleInstance(app_id)

    def handle_tray_icon_activated(self, reason):
        if reason == QSystemTrayIcon.Trigger:
            # 处理托盘图标被点击的事件
            pass

    def is_running(self):
        return self.instance.is_running()

    def message_received(self, message):
        # 处理接收到的消息
        pass

3. 创建一个QSingleInstance类，用于检测是否已经有实例在运行：

from PyQt5.QtNetwork import QLocalServer, QLocalSocket

class QSingleInstance:
    def __init__(self, app_id):
        self.app_id = app_id
        self.server = QLocalServer()
        self.server.newConnection.connect(self.handle_new_connection)
        self.server.listen(self.app_id)

    def is_running(self):
        socket = QLocalSocket()
        socket.connectToServer(self.app_id)
        if socket.waitForConnected(500):
            return True
        return False

    def handle_new_connection(self):
        socket = self.server.nextPendingConnection()
        if socket.waitForReadyRead(500):
            message = socket.readAll().data().decode()
            # 处理接收到的消息
            pass
        socket.disconnectFromServer()

4. 在主程序中使用单例模式：

if __name__ == "__main__":
    app_id = "MyApp"
    app = SingleApplication(sys.argv, app_id)
    if app.is_running():
        # 如果已经有实例在运行，则发送消息给已经运行的实例
        app.message_received("Hello from another instance!")
        sys.exit(0)
    else:
        # 如果没有实例在运行，则正常启动应用程序
        window = MainWindow()
        window.show()
        sys.exit(app.exec_())

这样就可以在PyQt5中实现单例模式了。