Python Pyqt5 Qlabel单击按钮后刷新

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel, QPushButton

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

        self.label = QLabel("Hello World", self)
        self.label.setGeometry(50, 50, 200, 30)

        self.button = QPushButton("刷新", self)
        self.button.setGeometry(50, 100, 100, 30)
        self.button.clicked.connect(self.refresh_label)

    def refresh_label(self):
        self.label.setText("按钮被点击了")

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())