如何在PyQt中的QGraphicsView旁邊添加菜單欄（QMainWindow）？

Question

在窗口上顯示帶有滾動條的圖片。 我們可以利用它。 我想將菜單欄添加到同一窗口。 我嘗試了以下操作，但沒有成功。 運行此程序時，窗口上沒有任何顯示。

#!/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些組件的子級，則在窗口中顯示，在您的情況下， self.y不是Example的子級，而只是一個屬性，可能的解決方案是將其設置為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()