PyQt: 计时器

import sys
from PyQt5.Qt import *


class Window(QWidget):
    def __init__(self):
        super().__init__()
        self.label = None
        self.button = None
        self.setWindowTitle("计时器")
        self.resize(300, 300)
        self.timer_id = None
        self.second_number = 10
        self.timer_interval = 1000
        self.setup_ui()
        self.custom_action()

    def setup_ui(self):
        self.label = QLabel(self)
        self.label.setText(str(self.second_number))
        self.label.move(100, 100)
        self.button = QPushButton(self)
        self.button.setText("开始计时")
        self.button.move(100, 200)

    def custom_action(self):
        self.button.clicked.connect(self.timer_start)

    def timerEvent(self, a0) -> None:
        self.second_number -= 1
        self.label.setText(str(self.second_number))
        self.resize(self.width()+10,self.height()+10)
        if self.second_number == 0:
            self.killTimer(self.timer_id)

    def timer_start(self):
        if self.second_number != 0:
            self.timer_id = self.startTimer(self.timer_interval)


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