如何使用鼠标动态调整QHBoxLayout和QGraphicsView大小？(Python，Pyqt4)

import sys
from PyQt4 import QtGui

class CustomGraphicsView(QtGui.QGraphicsView):
    def __init__(self, parent=None):
        super(CustomGraphicsView, self).__init__(parent)
        self.setRenderHint(QtGui.QPainter.Antialiasing)
        self.setViewportUpdateMode(QtGui.QGraphicsView.FullViewportUpdate)

        # 用于存储鼠标按下时的位置
        self.drag_start_position = None
        self.resize_start_size = None

    def mousePressEvent(self, event):
        if event.button() == QtCore.Qt.LeftButton:
            # 记录鼠标按下时的位置和视图的大小
            self.drag_start_position = event.pos()
            self.resize_start_size = self.size()

        super(CustomGraphicsView, self).mousePressEvent(event)

    def mouseMoveEvent(self, event):
        if event.buttons() == QtCore.Qt.LeftButton:
            # 计算鼠标移动的距离
            delta = event.pos() - self.drag_start_position

            # 更新视图的大小
            new_width = self.resize_start_size.width() + delta.x()
            new_height = self.resize_start_size.height() + delta.y()
            self.resize(new_width, new_height)

        super(CustomGraphicsView, self).mouseMoveEvent(event)

class MainWindow(QtGui.QMainWindow):
    def __init__(self):
        super(MainWindow, self).__init__()

        main_widget = QtGui.QWidget(self)
        self.setCentralWidget(main_widget)

        # 创建QHBoxLayout并添加CustomGraphicsView
        layout = QtGui.QHBoxLayout(main_widget)
        graphics_view = CustomGraphicsView()
        layout.addWidget(graphics_view)

        # 设置CustomGraphicsView的场景
        scene = QtGui.QGraphicsScene(self)
        graphics_view.setScene(scene)

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    main_win = MainWindow()
    main_win.show()
    sys.exit(app.exec_())