PyQt: QAbstractSpinBox 首次运行，文本框为空，验证及修复未执行，直接点击步长按钮情况的处理

import sys
from PyQt5.Qt import *


class CAbstractSpinBox(QAbstractSpinBox):
    def __init__(self, parent=None):
        super(CAbstractSpinBox, self).__init__(parent)
        self.flag = False

    def stepEnabled(self):
        # 如果文本框中的内容可以转为整形
        try:
            text = int(self.text())
        # 否则可判断为文本框为空。主要针对首次运行，无输入，验证及修复未执行，直接点击步长按钮的情况
        except:
            self.lineEdit().setText("1")
            self.flag = True
            return QAbstractSpinBox.StepNone
        else:
            if 1 < text < 9:
                return QAbstractSpinBox.StepUpEnabled | QAbstractSpinBox.StepDownEnabled
            elif text == 1:
                return QAbstractSpinBox.StepUpEnabled
            elif text == 9:
                return QAbstractSpinBox.StepDownEnabled
            else:
                return QAbstractSpinBox.StepNone

    def stepBy(self, steps: int) -> None:
        text = int(self.text()) + steps
        self.lineEdit().setText(str(text))

    def validate(self, input: str, pos: int):
        if len(input) == 0:
            return (QValidator.Intermediate, input, pos)
        else:
            try:
                input = int(input)
            except:
                return (QValidator.Invalid, input, pos)
            else:
                if 1 <= input <= 9:
                    return (QValidator.Acceptable, str(input), pos)
                elif input < 1 or input > 9:
                    return (QValidator.Invalid, str(input), pos)

    def fixup(self, input: str) -> str:
        return "1"


class Window(QWidget):
    def __init__(self):
        super().__init__()
        self.setup_ui()

    def setup_ui(self):
        self.setWindowTitle("Qt桌面应用程序")
        self.resize(300, 300)

        self.abstract_spin_box = CAbstractSpinBox(self)
        self.abstract_spin_box.resize(50, 30)
        self.abstract_spin_box.move(50, 50)


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