QWidgetAction在使用setDefaultWidget到QCheckBox时检查状态不更改

Question

我想要创建一个带有可检查列表的菜单。为了防止菜单在单击操作时关闭，我将DefaultWidget设置为QCheckBox。问题是，当我试图从操作中获得isClicked时，它似乎没有被同步到复选框。单击复选框时，如何获得要更改的操作的值？

tool_button = QtWidgets.QToolButton()
menu = QtWidgets.QMenu()

check_box = QtWidgets.QCheckBox(menu)
check_box.setText("abc")
check_box.setChecked(True)
action_button = QtWidgets.QWidgetAction(menu)
action_button.setDefaultWidget(check_box)

menu.addAction(action_button)
tool_button.setMenu(menu)

print(check_box.text()) # returns abc
print(check_box.isChecked()) # returns True
print(action_button.isChecked()) # returns False - it's not picking up the values from check_box

Answer 1

由于QWidgetAction充当任何类型小部件的某种容器，因此它无法知道它的defaultWidget是否能够支持像"isChecked“这样的bool状态，所以您必须提供它。

最简单的方法是为该操作子类一个特定的QWidgetAction类，并重写它的isChecked()方法，以便它根据其默认小部件返回选中的值。

from PyQt5 import QtWidgets

class CheckableWidgetAction(QtWidgets.QWidgetAction):
    def setDefaultWidget(self, widget):
        super().setDefaultWidget(widget)
        try:
            # if the widget has the toggled signal, connect that signal to the
            # triggered signal
            widget.toggled.connect(self.triggered)
        except:
            pass

    def isChecked(self):
        try:
            return self.defaultWidget().isChecked()
        except:
            # failsafe, in case no default widget has been set or the provided
            # widget doesn't have a "checked" property
            return super().isChecked()


class Test(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        layout = QtWidgets.QVBoxLayout(self)
        tool_button = QtWidgets.QToolButton()
        layout.addWidget(tool_button)
        menu = QtWidgets.QMenu()

        check_box = QtWidgets.QCheckBox(menu)
        check_box.setText("abc")
        check_box.setChecked(True)
        self.action_button = CheckableWidgetAction(menu)
        self.action_button.setDefaultWidget(check_box)
        self.action_button.triggered.connect(self.action_triggered)

        menu.addAction(self.action_button)
        tool_button.setMenu(menu)

        controlButton = QtWidgets.QPushButton('is checked?')
        layout.addWidget(controlButton)
        controlButton.clicked.connect(self.is_checked)

    def is_checked(self):
        print('checked is {}'.format(self.action_button.isChecked()))

    def action_triggered(self, state):
        print('triggered {}'.format(state))

if __name__ == '__main__':
    import sys
    a = QtWidgets.QApplication(sys.argv)
    test = Test()
    test.show()
    sys.exit(a.exec_())