QT-如何在QThread中使用QWidget？

from PyQt5.QtWidgets import QWidget, QApplication, QVBoxLayout
from PyQt5.QtCore import QThread
import sys

class CustomWidget(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        layout = QVBoxLayout()
        self.setLayout(layout)
    
    def paintEvent(self, event):
        # 在此处编写绘制界面的逻辑
        pass

class CustomThread(QThread):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.widget = CustomWidget()
        self.app = QApplication(sys.argv)
    
    def run(self):
        self.widget.setParent(self.app)
        self.widget.show()
        sys.exit(self.app.exec_())

# 在主线程中创建并启动自定义线程
thread = CustomThread()
thread.start()