如何使用按钮在 PyQt5 中的两个菜单栏之间切换？菜单栏消失

Question

我有两个自定义 QMenuBar 类 MyMenuBar0 和 MyMenuBar1，我想在按下按钮时从一个菜单栏切换到另一个。下面说明的问题是按下按钮会导致菜单消失。我应该如何设置以允许按钮在菜单之间切换？

示例 1（工作示例，不使用按钮）

当菜单栏作为主窗口的__init__ 方法的一部分进行更改时，一切正常。

class MyMainWindow(QtWidgets.QMainWindow):
    def __init__(self, *args):
        super().__init__(*args)
        self.setMenuBar( MyMenuBar0(self) ) #first menu bar set
        self.change_menu_bar()    #successful change to the second menu bar

    def change_menu_bar(self):
        self.setMenuBar( MyMenuBar1(self) )

示例 2（问题示例，尝试使用按钮）

当使用按钮重复上述操作时，按下按钮会导致菜单消失。

class MyMainWindow(QtWidgets.QMainWindow):
    def __init__(self, *args):
        super().__init__(*args)
        self.setMenuBar( MyMenuBar0(self) )
        button  = QtWidgets.QPushButton(self)
        button.clicked.connect( self.button_change_menu_bar )

    def button_change_menu_bar(self, a):
        self.setMenuBar( MyMenuBar1(self) ) #causes the menu bar to disappear

---

这里是重现问题的完整代码：

示例 1

import sys
from PyQt5 import QtWidgets


class MyMenuBar0(QtWidgets.QMenuBar):
    def __init__(self, parent):
        super().__init__(parent)
        menu        = self.addMenu('Menu 0')
        action0     = QtWidgets.QAction('Action 0', self)
        action1     = QtWidgets.QAction('Action 1', self)
        menu.addAction(action0)
        menu.addAction(action1)


class MyMenuBar1(QtWidgets.QMenuBar):
    def __init__(self, parent):
        super().__init__(parent)
        menu        = self.addMenu('Menu 1')
        action0     = QtWidgets.QAction('Action 2', self)
        action1     = QtWidgets.QAction('Action 3', self)
        menu.addAction(action0)
        menu.addAction(action1)


class MyMainWindow(QtWidgets.QMainWindow):
    def __init__(self, *args):
        super().__init__(*args)
        self.setMenuBar( MyMenuBar0(self) ) #first menu bar set
        self.change_menu_bar()    #successful change to the second menu bar

    def change_menu_bar(self):
        self.setMenuBar( MyMenuBar1(self) )


if __name__ == '__main__':
    app    = QtWidgets.QApplication(sys.argv)
    window = MyMainWindow()
    window.show()
    sys.exit(app.exec_())

---

示例 2

import sys
from PyQt5 import QtWidgets


class MyMenuBar0(QtWidgets.QMenuBar):
    def __init__(self, parent):
        super().__init__(parent)
        menu        = self.addMenu('Menu 0')
        action0     = QtWidgets.QAction('Action 0', self)
        action1     = QtWidgets.QAction('Action 1', self)
        menu.addAction(action0)
        menu.addAction(action1)


class MyMenuBar1(QtWidgets.QMenuBar):
    def __init__(self, parent):
        super().__init__(parent)
        menu        = self.addMenu('Menu 1')
        action0     = QtWidgets.QAction('Action 2', self)
        action1     = QtWidgets.QAction('Action 3', self)
        menu.addAction(action0)
        menu.addAction(action1)



class MyMainWindow(QtWidgets.QMainWindow):
    def __init__(self, *args):
        super().__init__(*args)
        self.setMenuBar( MyMenuBar0(self) )
        button  = QtWidgets.QPushButton(self)
        button.clicked.connect( self.button_change_menu_bar )

    def button_change_menu_bar(self, a):
        self.setMenuBar( MyMenuBar1(self) )  #causes the menu bar to disappear


if __name__ == '__main__':
    app    = QtWidgets.QApplication(sys.argv)
    window = MyMainWindow()
    window.show()
    sys.exit(app.exec_())

Answer 1

您希望将两个菜单栏都放入 setUI 方法并简化您的代码。这可能对你有用。

class MyMainWindow(QtWidgets.QMainWindow):
    def __init__(self, *args):
        super().__init__(*args)
        self.setUI()

    def setUI(self):
        self.MenuBar0 = QMenuBar()
        # ...
        self.menuBar1 = QMenuBar()
        # ...
        button  = QPushButton('Toggle')
        button.clicked.connect( self.button_change_menu_bar )

    def button_change_menu_bar(self):
        state = self.menuBar0.isVisible()
        self.menuBar0.setVisible(not state)
        self.menuBar1.setVisible(state)