如何在pyqt5中制作一个由按钮触发的圆圈？

from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton, QGraphicsScene, QGraphicsView
from PyQt5.QtCore import Qt, QRectF
from PyQt5.QtGui import QPainter, QBrush, QColor

class CircleView(QGraphicsView):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.scene = QGraphicsScene(self)
        self.setScene(self.scene)
        self.setRenderHint(QPainter.Antialiasing)
        self.setFixedSize(400, 400)
        self.circle_radius = 50
        self.circle_color = Qt.red
        self.circle_position = QRectF(175, 175, self.circle_radius * 2, self.circle_radius * 2)

    def paintEvent(self, event):
        painter = QPainter(self.viewport())
        painter.setRenderHint(QPainter.Antialiasing)
        brush = QBrush(self.circle_color)
        painter.setBrush(brush)
        painter.drawEllipse(self.circle_position)

    def mousePressEvent(self, event):
        self.circle_color = Qt.blue
        self.update()

    def mouseReleaseEvent(self, event):
        self.circle_color = Qt.red
        self.update()

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("Circle Button")
        self.button = QPushButton("Click Me", self)
        self.button.clicked.connect(self.on_button_clicked)
        self.circle_view = CircleView(self)
        self.setCentralWidget(self.circle_view)

    def on_button_clicked(self):
        self.circle_view.circle_color = Qt.green
        self.circle_view.update()

if __name__ == "__main__":
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()