pyqt5多线程更新UI小例子

import sys
from PyQt5.QtWidgets import QApplication,QWidget,QPushButton,QHBoxLayout,QLabel
from PyQt5.QtCore import pyqtSignal, QThread
import time

class ui(QWidget):

    def __init__(self):
        super().__init__()
        wind=QWidget(self)
        wind.setWindowTitle('小例子')
        wind.resize(300,200)
        layou=QHBoxLayout(self)
        self.btn = QPushButton('开始线程',self)
        self.btn2 = QPushButton('结束线程',self)
        self.label=QLabel(self)
        layou.addWidget(self.btn)
        layou.addWidget(self.btn2)
        layou.addWidget(self.label)
        wind.setLayout(layou)
        self.btn.clicked.connect(self.A)
        self.btn2.clicked.connect(self.B)
        self.btn2.setEnabled(False)
        self.my_thread=thread()
        self.my_thread.testsing.connect(self.labelsetText)
        # self.my_thread.sing.connect(self.B)
        self.my_thread.sing2.connect(self.B)

    def labelsetText(self,text):
        self.label.setText(text)
    def A(self):
        self.btn.setEnabled(False)
        self.btn.setText('已被禁用')
        self.my_thread.start()
        self.btn2.setEnabled(True)
        self.btn2.setText('结束线程')
    def B(self):
        self.my_thread.terminate()
        self.btn.setEnabled(True)
        self.btn.setText('开始线程')
        self.btn2.setEnabled(False)
        self.btn2.setText('已被禁用')

class thread(QThread):
    testsing=pyqtSignal(str)
    sing2 = pyqtSignal()
    def __init__(self):
        super().__init__()
    def run(self):
        for i in range(10):
            time.sleep(1)
            self.testsing.emit(str(i))
            print(i)
        self.sing2.emit()

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