如何在 PyQt 中正确使用 QThread
QThread 背景
QThread 允许您创建并在单独的线程中执行任务,并行化可能会冻结用户界面的操作。然而,博客文章 https://mayaposch.wordpress.com/2011/11/01/how-to-really-truly-use-qthreads-the-full-explanation/ 建议不要重新实现 run 方法来利用 QThreads .
正确的 QThread 用法
不要操作 run 方法,而是考虑以下 PyQt 中 QThread 使用的最佳实践:
示例用法
下面的代码提供了一个使用信号与 GUI 进行通信的单独工作线程的示例:
<code class="python">from PyQt4 import QtGui, QtCore import sys import random class Example(QtCore.QObject): signalStatus = QtCore.pyqtSignal(str) def __init__(self, parent=None): super(self.__class__, self).__init__(parent) # Create a gui object. self.gui = Window() # Create a new worker thread. self.createWorkerThread() # Make any cross object connections. self._connectSignals() self.gui.show() def _connectSignals(self): self.gui.button_cancel.clicked.connect(self.forceWorkerReset) self.signalStatus.connect(self.gui.updateStatus) self.parent().aboutToQuit.connect(self.forceWorkerQuit) def createWorkerThread(self): # Setup the worker object and the worker_thread. self.worker = WorkerObject() self.worker_thread = QtCore.QThread() self.worker.moveToThread(self.worker_thread) self.worker_thread.start() # Connect any worker signals self.worker.signalStatus.connect(self.gui.updateStatus) self.gui.button_start.clicked.connect(self.worker.startWork) def forceWorkerReset(self): if self.worker_thread.isRunning(): print('Terminating thread.') self.worker_thread.terminate() print('Waiting for thread termination.') self.worker_thread.wait() self.signalStatus.emit('Idle.') print('building new working object.') self.createWorkerThread() def forceWorkerQuit(self): if self.worker_thread.isRunning(): self.worker_thread.terminate() self.worker_thread.wait() class WorkerObject(QtCore.QObject): signalStatus = QtCore.pyqtSignal(str) def __init__(self, parent=None): super(self.__class__, self).__init__(parent) @QtCore.pyqtSlot() def startWork(self): for ii in range(7): number = random.randint(0,5000**ii) self.signalStatus.emit('Iteration: {}, Factoring: {}'.format(ii, number)) factors = self.primeFactors(number) print('Number: ', number, 'Factors: ', factors) self.signalStatus.emit('Idle.') def primeFactors(self, n): i = 2 factors = [] while i * i <= n: if n % i: i += 1 else: n //= i factors.append(i) if n > 1: factors.append(n) return factors class Window(QtGui.QWidget): def __init__(self): QtGui.QWidget.__init__(self) self.button_start = QtGui.QPushButton('Start', self) self.button_cancel = QtGui.QPushButton('Cancel', self) self.label_status = QtGui.QLabel('', self) layout = QtGui.QVBoxLayout(self) layout.addWidget(self.button_start) layout.addWidget(self.button_cancel) layout.addWidget(self.label_status) self.setFixedSize(400, 200) @QtCore.pyqtSlot(str) def updateStatus(self, status): self.label_status.setText(status) if __name__=='__main__': app = QtGui.QApplication(sys.argv) example = Example(app) sys.exit(app.exec_())</code>
在此示例中,GUI 和工作线程是单独的对象通过信号进行通信。 GUI 监听状态更新,而工作线程执行计算并发回进度。
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