如何在PyQt中添加菜单栏（QMainWindow）和QGraphicsView？

Question

在窗口上显示带有滚动条的图片。我们可以借鉴它。我想在同一个窗口添加一个菜单栏。我试过以下，它没有用。运行时，窗口上没有显示任何内容。

#!/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窗口，则窗口显示窗口小部件，在您的情况下interface Data { public function details(string $name); } class Company { private $title; public function getTitle():Data { return $this->title; } public function setTitle(Data $title) { $this->title=$title } } ..... ..... 不是self.y的子窗口，但只有属性，可能的解决方案是将其设为Example：

centralWidget