一般情况单线程就可以很好的完成任务,但是对于GUI程序来说,单线程就不能完全满足需求。如果有耗时流程,在单线程的情况下,界面操作就会卡死,直到耗时操作完成,才会响应界面操作。为了解决这个问题,PyQt提供了两个异步操作的对象:QThread和QTimer。

QTimer

功能:定时器,固定时间触发消息

start(milliseconds) 启动定时器,单位是毫秒 stop() 停止定时器

QThread

功能:开辟一个线程,和主线程并行执行

start() sleep(seconds) 线程休眠,单位秒

需求:分别使用QThread和QTimer

import sys
from PyQt5.QtCore import QTimer
from PyQt5.QtWidgets import QApplication, QWidget, QProgressBar
class MyWidget(QWidget):
    def __init__(self):
        super(MyWidget, self).__init__()
        self.currentValue = 0
        self.progessBar = QProgressBar(self)
        self.progessBar.resize(200, 50)
        self.progessBar.move(20, 20)
        self.progessBar.setValue(self.currentValue)
        # 定义一个定时器并启动定时器
        self.time = QTimer()
        self.time.timeout.connect(self.upgradeProgress)
        self.time.start(200)
    def upgradeProgress(self):
        self.currentValue = (self.currentValue + 1) % 101
        self.progessBar.setValue(self.currentValue)
if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = MyWidget()
    w.resize(500, 300)
    w.move(300, 300)
    w.setWindowTitle('Simple')
    w.show()
    sys.exit(app.exec_())
import sys
from PyQt5.QtCore import QThread, pyqtSignal
from PyQt5.QtWidgets import QApplication, QWidget, QProgressBar
class MyWorker(QThread):
    timeout = pyqtSignal()
    def __init__(self):
        super(MyWorker, self).__init__()
    def run(self):
        while True:
            self.timeout.emit()
            self.sleep(1)
class MyWidget(QWidget):
    def __init__(self):
        super(MyWidget, self).__init__()
        self.currentValue = 0
        self.progessBar = QProgressBar(self)
        self.progessBar.resize(200, 50)
        self.progessBar.move(20, 20)
        self.progessBar.setValue(self.currentValue)
        self.worker = MyWorker()
        self.worker.timeout.connect(self.upgradeProgress)
        self.worker.start()
    def upgradeProgress(self):
        self.currentValue = (self.currentValue + 1) % 101
        self.progessBar.setValue(self.currentValue)
if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = MyWidget()
    w.resize(500, 300)
    w.move(300, 300)
    w.setWindowTitle('Simple')
    w.show()
    sys.exit(app.exec_())