import sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *


class spindemo(QWidget):
  def __init__(self, parent=None):
    super(spindemo, self).__init__(parent)
    self.setWindowTitle("SpinBox 例子")
    self.resize(300, 100)

    layout = QVBoxLayout()
    self.l1 = QLabel("current value:")
    self.l1.setAlignment(Qt.AlignCenter)
    layout.addWidget(self.l1)
    self.sp = QSpinBox()
    layout.addWidget(self.sp)
    self.sp.valueChanged.connect(self.valuechange)
    self.setLayout(layout)

  def valuechange(self):
    self.l1.setText("current value:" + str(self.sp.value()))


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