我试图用一个队列运行多个进程，并使用QProcess获取所有进程的输出，但是我遇到了两个问题。我正在使用QSpinBox来设置要同时运行的最大进程，并且我可以使所有线程在主线程中正常运行，或者如果我在QObject中使用进程运行循环，但是我在无法使其在QThread中正常工作。
我知道不需要与QProcess一起使用线程，但是对于循环，我几乎别无选择。在主线程中运行时，它会暂时冻结，直到进程启动为止，而我希望它运行得更流畅。
除非尝试使用QThread之类的东西，否则尝试运行_process.waitForFinished()中的进程时我什么都不会出错，但是问题是进程一次只能运行一个。
有没有人有任何建议可以使其正常工作？我目前正在使用Pyside2，但是对Pyside2或PyQt5的回答会很好。谢谢。
import queue
import sys
from PySide2.QtCore import QProcess, QTextCodec, QThread, Qt
from PySide2.QtWidgets import QApplication, QWidget, QSpinBox, \
QPushButton, QVBoxLayout
class Window(QWidget):
def __init__(self):
QWidget.__init__(self)
self.setAttribute(Qt.WA_DeleteOnClose, True)
self.queue = queue.Queue()
layout = QVBoxLayout(self)
self.startBtn = QPushButton('Start', clicked=self.addToQueue)
self.spinBox = QSpinBox(value=3)
layout.addWidget(self.spinBox)
layout.addWidget(self.startBtn)
self.taskList = ['my.exe -value','my.exe -value','my.exe -value','my.exe -value',
'my.exe -value','my.exe -value','my.exe -value','my.exe -value']
def addToQueue(self):
for i in self.taskList:
self.queue.put(i)
self.sendToThread()
def sendToThread(self):
vals = {'max': self.spinBox.value()}
self.taskThread = TaskThread(self.queue, vals)
self.taskThread.start()
def closeEvent(self, event):
event.accept()
class TaskThread(QThread):
def __init__(self, queue=None, vals=None, parent=None):
QThread.__init__(self, parent)
self.queue = queue
self.vals = vals
self.maxProcs = self.vals.get('max')
self.procCount = 0
def run(self):
self.start_procs()
def start_procs(self):
while not self.queue.empty() and self.procCount < self.maxProcs:
cmd = self.queue.get()
_process = QProcess(self)
_process.setProcessChannelMode(QProcess.MergedChannels)
self.codec = QTextCodec.codecForLocale()
self._decoder_stdout = self.codec.makeDecoder()
_process.readyReadStandardOutput.connect(lambda process=_process: self._ready_read_standard_output(process))
_process.started.connect(self.procStarted)
_process.finished.connect(self.procFinished)
_process.finished.connect(self.decreaseCount)
_process.finished.connect(self.start_procs)
_process.start(cmd)
self.procCount += 1
def _ready_read_standard_output(self, process):
self.out = process.readAllStandardOutput()
self.text = self._decoder_stdout.toUnicode(self.out)
print(self.text)
def decreaseCount(self):
if self.procCount <= 0:
pass
else:
self.procCount -= 1
def procStarted(self):
print('started')
def procFinished(self):
print('finished')
if __name__ == '__main__':
app = QApplication(sys.argv)
window = Window()
window.resize(200, 100)
window.show()
sys.exit(app.exec_())
答案 0 :(得分：2)
启动进程时，并不表示它已启动，因为它可能存在执行问题，因此，在第一次启动时，最好等待该进程启动或无法启动以下进程，以满足以下要求：正在运行的进程数小于最大值，或者不再执行任务或尚未启动。
另一方面，我还实现了停止任务，这意味着不再添加任何任务，但是停止之前正在执行的任务将继续执行。
如果将最大值更改为较低的值，则在满足条件之前不会抛出更多任务。
考虑到上述情况，没有必要使用线程
import queue
from PySide2 import QtCore, QtGui, QtWidgets
class TaskManager(QtCore.QObject):
messageChanged = QtCore.Signal(str)
numbersTaskRunningChanged = QtCore.Signal(int)
def __init__(self, parent=None):
super(TaskManager, self).__init__(parent)
self._max_task = 1
self._queue = queue.Queue()
self._numbers_task_running = 0
self._running = False
def setMaxTask(self, max_task):
self._max_task = max_task
if self._running:
self.call_task()
def maxTask(self):
return self._max_task
def appendTask(self, task):
self._queue.put(task)
self.call_task()
def start(self):
self._running = True
self.call_task()
def stop(self):
self._running = False
def call_task(self):
if self._numbers_task_running < self.maxTask() and not self._queue.empty() and self._running:
cmd = self._queue.get()
process = QtCore.QProcess(self)
process.setProcessChannelMode(QtCore.QProcess.MergedChannels)
process.readyReadStandardOutput.connect(self.on_readyReadStandardOutput)
process.finished.connect(self.on_finished)
process.started.connect(self.on_started)
process.errorOccurred.connect(self.on_errorOccurred)
process.start(cmd)
def on_readyReadStandardOutput(self):
codec = QtCore.QTextCodec.codecForLocale()
decoder_stdout = codec.makeDecoder()
process = self.sender()
text = decoder_stdout.toUnicode(process.readAllStandardOutput())
self.messageChanged.emit(text)
def on_errorOccurred(self, error):
process = self.sender()
print("error: ", error, "-", " ".join([process.program()] + process.arguments()))
self.call_task()
def on_finished(self):
process = self.sender()
self._numbers_task_running -= 1
self.numbersTaskRunningChanged.emit(self._numbers_task_running)
self.call_task()
def on_started(self):
process = self.sender()
print("started: ", " ".join([process.program()] + process.arguments()))
self._numbers_task_running += 1
self.numbersTaskRunningChanged.emit(self._numbers_task_running)
self.call_task()
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Widget, self).__init__(parent)
self.setAttribute(QtCore.Qt.WA_DeleteOnClose, True)
manager = TaskManager(self)
task_list = # ...
for task in task_list:
manager.appendTask(task)
button_start = QtWidgets.QPushButton("Start", clicked=manager.start)
button_stop = QtWidgets.QPushButton("Stop", clicked=manager.stop)
label = QtWidgets.QLabel("0", alignment=QtCore.Qt.AlignCenter)
manager.numbersTaskRunningChanged.connect(label.setNum)
spinBox = QtWidgets.QSpinBox()
spinBox.valueChanged.connect(manager.setMaxTask)
spinBox.setValue(3)
textEdit = QtWidgets.QTextEdit()
manager.messageChanged.connect(textEdit.append)
lay = QtWidgets.QVBoxLayout(self)
lay.addWidget(spinBox)
lay.addWidget(button_start)
lay.addWidget(button_stop)
lay.addWidget(label)
lay.addWidget(textEdit)
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())