Pyqt-线程

1、示例1

#! /usr/bin/env python
# -*- coding: utf-8 -*-

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

class MainWidget(QWidget):
    def __init__(self, parent=None):
        super(MainWidget, self).__init__(parent)
        self.thread = Worker()
        self.listFile = QListWidget()
        self.btnStart = QPushButton('开始')

        layout = QGridLayout(self)
        layout.addWidget(self.listFile, 0, 0, 1, 2)
        layout.addWidget(self.btnStart, 1, 1)

        self.btnStart.clicked.connect(self.slotStart)   # 启动线程
        self.thread.sinOut.connect(self.slotAdd)        # 将信号连接到slotAdd，信号由线程每隔2s发送一次

    def slotAdd(self, file_list):
        self.listFile.addItem(file_list)

    def slotStart(self):
        self.btnStart.setEnabled(False)
        self.thread.start()

# 新的线程：创建一个信号，该信号每隔2s发送一次
# 线程启动后会自动开始执行run()函数
class Worker(QThread):
    sinOut = pyqtSignal(str)    # 创建一个信号，信号必须在类创建时定义，不能在类创建后作为类的属性动态添加进来

    def __init__(self, parent=None):
        super(Worker, self).__init__(parent)
        self.working = True
        self.num = 0
    def __del__(self):
        self.working = False
        self.wait()
    def run(self):
        while self.working == True:
            file_str = 'File index{0}'.format(self.num)
            self.num += 1
            # 发射信号
            self.sinOut.emit(file_str)
            # 线程休眠2秒
            self.sleep(2)

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)

    win = MainWidget()
    win.show()

    sys.exit(app.exec())

运行结果：点下开始按钮，每隔2s添加一个条目

 2、示例2

#! /usr/bin/env python
# -*- coding: utf-8 -*-

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

global sec
sec = 0

class MainWidget(QWidget):
    def __init__(self, parent=None):
        super(MainWidget, self).__init__(parent)
        self.widget = QWidget()
        self.widget.resize(300, 120)

        self.lcdNum = QLCDNumber()
        self.button = QPushButton("测试")
        self.timer = QTimer()

        layout = QVBoxLayout(self)
        layout.addWidget(self.lcdNum)
        layout.addWidget(self.button)

        self.button.clicked.connect(self.work)  #
        self.timer.timeout.connect(self.setTime)  # 定时任务，每隔100ms QLCDNumber值自加

    def setTime(self):
        global sec
        sec += 1
        self.lcdNum.display(sec)

# 定义一个任务，该任务启动一个1000ms的定时器后开始一段非常耗时的操作(用for循环模拟)
    def work(self):
        self.timer.start(1000)
        for i in range(2000000000):  # 模拟一段非常耗时的计算，他会阻塞主线程app.exec()，从而让窗口停止响应
            pass
        self.timer.stop()



if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)

    win = MainWidget()
    win.show()

    sys.exit(app.exec())  # 这是主线程

运行结果：点下测试按钮，程序不响应或者卡斯崩溃

 3、示例3

#! /usr/bin/env python
# -*- coding: utf-8 -*-

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

global sec
sec = 0

class MainWidget(QWidget):
    def __init__(self, parent=None):
        super(MainWidget, self).__init__(parent)
        self.widget = QWidget()
        self.widget.resize(300, 120)
        # 控件
        self.lcdNum = QLCDNumber()
        self.button = QPushButton("测试")
        self.timer = QTimer()
        self.workThread = WorkThread()
        # 布局
        layout = QVBoxLayout(self)
        layout.addWidget(self.lcdNum)
        layout.addWidget(self.button)
        #信号与槽函数
        self.button.clicked.connect(self.work)  # 按钮按下触发: 定时器开启，新线程开启
        self.timer.timeout.connect(self.setTime)  # 每隔1000ms触发: QLCDNumber值自加

    def setTime(self):
        global sec
        sec += 1
        self.lcdNum.display(sec)

    def timeStop(self):
        self.timer.stop()
        print("运行结束用时", self.lcdNum.value())
        global sec
        sec = 0

    # 开启定时器和新线程
    def work(self):
        self.timer.start(1000)
        self.workThread.start()
        self.workThread.trigger.connect(self.timeStop)  # 线程结束时触发timeStop函数

# 新的线程：模拟一段耗时的计算或其他操作(较长时间的死循环)
class WorkThread(QThread):
    trigger = pyqtSignal()

    def __init__(self):
        super(WorkThread,self).__init__()

    def run(self):
        for i in range(400000000):  # 模拟一段非常耗时的计算，他会阻塞主线程app.exec()，从而让窗口停止响应
            pass
        self.trigger.emit()

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)

    win = MainWidget()
    win.show()

    sys.exit(app.exec())  # 这是主线程

运行结果：界面不会出现卡顿情况了，耗时计算完成后计数停止并print所用时间