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

class spindemo(QWidget):
  def __init__(self,parent=None):
    super(spindemo, self).__init__(parent)
    #设置标题与初始大小
    self.setWindowTitle('SpinBox 例子')
    self.resize(300,100)

    #垂直布局
    layout=QVBoxLayout()

    #创建按钮并设置居中
    self.l1=QLabel('current value')
    self.l1.setAlignment(Qt.AlignCenter)

    layout.addWidget(self.l1)

    #创建计数器，并添加控件，数值改变时发射信号触发绑定事件
    self.sp=QSpinBox()
    layout.addWidget(self.sp)
    self.sp.valueChanged.connect(self.Valuechange)


    self.setLayout(layout)

  def Valuechange(self):
    #显示当前计数器地数值
    self.l1.setText('current value:'+str(self.sp.value()))
if __name__ == '__main__':
  app=QApplication(sys.argv)
  ex=spindemo()
  ex.show()
  sys.exit(app.exec_())

self.sp.valueChanged.connect(self.Valuechange)

self.l1.setText('current value:'+str(self.sp.value()))