如何在PyQt中添加QGraphicsView旁边的菜单栏（QMainWindow）？

Question

在窗口上用滚动条显示图片。我们可以借鉴。我想在同一个窗口中添加一个菜单栏。我试过以下方法，但没用。运行此程序时，窗口上没有显示任何内容。在

#!/usr/bin/env python

from PyQt5.QtCore import (QLineF, QPointF, QRectF, Qt)
from PyQt5.QtGui import (QIcon, QBrush, QColor, QPainter, QPixmap)
from PyQt5.QtWidgets import (QAction, QMainWindow, QApplication, QGraphicsView, QGraphicsScene, QGraphicsItem,
                             QGridLayout, QVBoxLayout, QHBoxLayout,
                             QLabel, QLineEdit, QPushButton)

class TicTacToe(QGraphicsItem):
    def __init__(self):
        super(TicTacToe, self).__init__()

    def paint(self, painter, option, widget):
        painter.setPen(Qt.black)
        painter.drawLine(0,100,300,100)


    def boundingRect(self):
        return QRectF(0,0,300,300)

    def mousePressEvent(self, event):
        pos = event.pos()
        self.select(int(pos.x()/100), int(pos.y()/100))
        self.update()
        super(TicTacToe, self).mousePressEvent(event)

class MyGraphicsView(QGraphicsView):
    def __init__(self):
        super(MyGraphicsView, self).__init__()
        scene = QGraphicsScene(self)
        self.tic_tac_toe = TicTacToe()
        scene.addItem(self.tic_tac_toe)

        scene.addPixmap(QPixmap("exit.png"))

        self.setScene(scene)
        self.setCacheMode(QGraphicsView.CacheBackground)
        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)


    def keyPressEvent(self, event):
        key = event.key()
        if key == Qt.Key_R:
            self.tic_tac_toe.reset()
        super(MyGraphicsView, self).keyPressEvent(event)

class Example(QMainWindow):

    def __init__(self):
        super(Example, self).__init__()

        self.y = MyGraphicsView()

        self.initUI()


    def initUI(self):               

        menubar = self.menuBar()
        menu = menubar.addMenu('File')
        db_action = menu.addAction("Open file")

        self.setGeometry(30, 30, 30, 20)
        self.setWindowTitle('Menubar')    
        self.show()        


if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    mainWindow = Example()

    mainWindow.showFullScreen()
    sys.exit(app.exec_())

Answer 1

如果窗口小部件是窗口某个组件的子控件，则在您的示例中，self.y不是{}的子控件，而只是一个属性，一个可能的解决方案是将其设置为centralWidget：

class Example(QMainWindow):

    def __init__(self):
        super(Example, self).__init__()

        self.y = MyGraphicsView()
        self.setCentralWidget(self.y)

        self.initUI()


    def initUI(self):               

        menubar = self.menuBar()
        menu = menubar.addMenu('File')
        db_action = menu.addAction("Open file")

        self.setGeometry(30, 30, 30, 20)
        self.setWindowTitle('Menubar')    
        self.show()