PyQt:如何更改customContextMenu触发器？

from PyQt5.QtWidgets import QApplication, QMainWindow, QMenu, QAction
from PyQt5.QtCore import Qt

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        # 创建一个动作
        self.context_action = QAction("Context Action", self)
        self.context_action.triggered.connect(self.on_context_action)

        # 创建一个上下文菜单
        self.context_menu = QMenu(self)
        self.context_menu.addAction(self.context_action)

        # 连接键盘事件
        self.setContextMenuPolicy(Qt.CustomContextMenu)
        self.customContextMenuRequested.connect(self.show_context_menu)

    def show_context_menu(self, pos):
        # 这里可以根据pos或其他条件决定是否显示菜单
        self.context_menu.exec_(self.mapToGlobal(pos))

    def on_context_action(self):
        print("Context action triggered!")

    def keyPressEvent(self, event):
        if event.key() == Qt.Key_F1:  # 假设F1键触发上下文菜单
            self.show_context_menu(self.cursor().pos())
        else:
            super().keyPressEvent(event)

app = QApplication([])
window = MainWindow()
window.show()
app.exec_()