pyqt5-多线程QThread类

要实现多线程，我们要先继承QThread类并重新实现其中的run()函数，也就是说把耗时的操作放入run()函数中

 1 import sys
 2 from PyQt5.QtCore import Qt, QThread,pyqtSignal
 3 from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QLabel, QVBoxLayout,QHBoxLayout
 4 
 5 
 6 class Demo(QWidget):
 7     def __init__(self):
 8         super(Demo, self).__init__()
 9 
10         self.button = QPushButton('开始', self)
11         self.button.clicked.connect(self.count_func)
12         self.button_2 = QPushButton('停止', self)
13         self.button_2.clicked.connect(self.stop_count_func)
14 
15         self.label = QLabel('0', self)
16         self.label.setAlignment(Qt.AlignCenter)
17 
18         self.my_thread = MyThread()#实例化线程对象
19         self.my_thread.my_signal.connect(self.set_label_func)
20         #线程自定义信号连接的槽函数
21 
22         self.h_layout = QHBoxLayout()
23         self.v_layout = QVBoxLayout()
24         self.h_layout.addWidget(self.button)
25         self.h_layout.addWidget(self.button_2)
26         self.v_layout.addWidget(self.label)
27         self.v_layout.addLayout(self.h_layout)
28         self.setLayout(self.v_layout)
29 
30 
31     def stop_count_func(self):
32         self.my_thread.is_on = False
33         self.my_thread.count = 0
34 
35     def count_func(self):
36         self.my_thread.is_on = True
37         self.my_thread.start()#启动线程
38 
39     def set_label_func(self, num):
40         self.label.setText(num)
41         #由于自定义信号时自动传递一个字符串参数，所以在这个槽函数中要接受一个参数
42 
43 
44 class MyThread(QThread):#线程类
45     my_signal = pyqtSignal(str)  #自定义信号对象。参数str就代表这个信号可以传一个字符串
46     def __init__(self):
47         super(MyThread, self).__init__()
48         self.count = 0
49         self.is_on = True
50 
51 
52     def run(self): #线程执行函数
53         while self.is_on :
54             print(self.count)
55             self.count += 1
56             self.my_signal.emit(str(self.count))  #释放自定义的信号
57             #通过自定义信号把str(self.count)传递给槽函数
58 
59             self.sleep(1)  #本线程睡眠n秒【是QThread函数】
60 
61 
62 if __name__ == '__main__':
63     app = QApplication(sys.argv)
64     demo = Demo()
65     demo.show()
66     sys.exit(app.exec_())