pyqt 从线程线程发出信号
pyqt emit signal from threading thread
我正在尝试从多个线程更新 pyqt QProgressBar，据我所知，最好的方法是将信号发射回主 GUI 线程（我尝试传递 QProgressBar反对工作线程，尽管它似乎确实有效，但我在解释器中收到了大量警告）。在下面的代码中，我设置了一个 progressSignal 信号并将其连接到一个线程（目前）只打印发出的任何内容。然后我从每个线程发出总百分比。我知道这在线程外起作用，只需在第 47 行中抛出一个随机发射，它确实会通过。然而，第 36 行的发射不会触发任何东西，所以它似乎永远不会通过...
import Queue, threading
from PyQt4 import QtCore
import shutil
import profile
fileQueue = Queue.Queue()
class Communicate(QtCore.QObject):
progressSignal = QtCore.pyqtSignal(int)
class ThreadedCopy:
totalFiles = 0
copyCount = 0
lock = threading.Lock()
def __init__(self, inputList, progressBar="Undefined"):
self.totalFiles = len(inputList)
self.c = Communicate()
self.c.progressSignal.connect(self.updateProgressBar)
print str(self.totalFiles) + " files to copy."
self.threadWorkerCopy(inputList)
def CopyWorker(self):
while True:
self.c.progressSignal.emit(2000)
fileName = fileQueue.get()
shutil.copy(fileName[0], fileName[1])
fileQueue.task_done()
with self.lock:
self.copyCount += 1
percent = (self.copyCount * 100) / self.totalFiles
self.c.progressSignal.emit(percent)
def threadWorkerCopy(self, fileNameList):
for i in range(16):
t = threading.Thread(target=self.CopyWorker)
t.daemon = True
t.start()
for fileName in fileNameList:
fileQueue.put(fileName)
fileQueue.join()
self.c.progressSignal.emit(1000)
def updateProgressBar(self, percent):
print percent
更新：
这是带有图形用户界面的示例。这个运行但非常不稳定，它经常崩溃并且 UI 做了一些奇怪的事情（进度条没有完成，等等）
Main.py:
import sys, os
import MultithreadedCopy_5
from PyQt4 import QtCore, QtGui
def grabFiles(path):
# gets all files (not folders) in a directory
for file in os.listdir(path):
if os.path.isfile(os.path.join(path, file)):
yield os.path.join(path, file)
class MainWin(QtGui.QWidget):
def __init__(self):
super(MainWin, self).__init__()
self.initUI()
def initUI(self):
self.progress = QtGui.QProgressBar()
box = QtGui.QVBoxLayout()
box.addWidget(self.progress)
goBtn = QtGui.QPushButton("Start copy")
box.addWidget(goBtn)
self.setLayout(box)
goBtn.clicked.connect(self.startCopy)
def startCopy(self):
files = grabFiles("folder/with/files")
fileList = []
for file in files:
fileList.append([file,"folder/to/copy/to"])
MultithreadedCopy_5.ThreadedCopy(fileList, self.progress)
def main():
app = QtGui.QApplication(sys.argv)
ex = MainWin()
ex.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()
MultithreadedCopy_5.py:
import Queue, threading
from PyQt4 import QtCore
import shutil
import profile
fileQueue = Queue.Queue()
class Communicate(QtCore.QObject):
progressSignal = QtCore.pyqtSignal(int)
class ThreadedCopy:
totalFiles = 0
copyCount = 0
lock = threading.Lock()
def __init__(self, inputList, progressBar="Undefined"):
self.progressBar = progressBar
self.totalFiles = len(inputList)
self.c = Communicate()
self.c.progressSignal.connect(self.updateProgressBar, QtCore.Qt.DirectConnection)
print str(self.totalFiles) + " files to copy."
self.threadWorkerCopy(inputList)
def CopyWorker(self):
while True:
fileName = fileQueue.get()
shutil.copy(fileName[0], fileName[1])
fileQueue.task_done()
with self.lock:
self.copyCount += 1
percent = (self.copyCount * 100) / self.totalFiles
self.c.progressSignal.emit(percent)
def threadWorkerCopy(self, fileNameList):
for i in range(16):
t = threading.Thread(target=self.CopyWorker)
t.daemon = True
t.start()
for fileName in fileNameList:
fileQueue.put(fileName)
fileQueue.join()
def updateProgressBar(self, percent):
self.progressBar.setValue(percent)
#profile.run('ThreadedCopy()')
主要问题是发送信号和接收信号之间的时间延迟，我们可以使用 processEvents():
来减少时间
You can call this function occasionally when your program is busy
performing a long operation (e.g. copying a file).
def CopyWorker(self):
while True:
fileName = fileQueue.get()
shutil.copy(fileName[0], fileName[1])
fileQueue.task_done()
with self.lock:
self.copyCount += 1
print(self.copyCount)
percent = (self.copyCount * 100) / self.totalFiles
self.c.progressSignal.emit(percent)
QtCore.QCoreApplication.processEvents()
你的例子有两个主要问题。
首先，发出信号的对象是在 main/gui 线程中创建的，因此它发出的任何信号都不是跨线程的，因此不是线程安全的。显而易见的解决方案是在工作线程的目标函数内部创建信号对象——这意味着每个线程必须有一个单独的实例。
其次，目标函数内的 while 循环永远不会终止，这意味着每个 ThreadedCopy 对象将在当前复制操作完成后保持活动状态。由于所有这些对象共享同一个队列，如果试图重复复制操作，行为将变得不可预测。显而易见的解决方案是一旦队列为空就跳出 while 循环。
下面是 MultithreadedCopy_5.py 的重写，应该可以解决这些问题。但是，如评论中所述，我仍然强烈建议在这种情况下使用 QThread 而不是 python 线程，因为它可能会提供更强大且更易于维护的解决方案。
import Queue, threading
from PyQt4 import QtCore
import shutil
import profile
fileQueue = Queue.Queue()
class Communicate(QtCore.QObject):
progressSignal = QtCore.pyqtSignal(int)
class ThreadedCopy:
totalFiles = 0
copyCount = 0
lock = threading.Lock()
def __init__(self, inputList, progressBar="Undefined"):
self.progressBar = progressBar
self.totalFiles = len(inputList)
print str(self.totalFiles) + " files to copy."
self.threadWorkerCopy(inputList)
def CopyWorker(self):
c = Communicate()
c.progressSignal.connect(self.updateProgressBar)
while True:
try:
fileName = fileQueue.get(False)
except Queue.Empty:
break
else:
shutil.copy(fileName[0], fileName[1])
with self.lock:
self.copyCount += 1
percent = (self.copyCount * 100) / self.totalFiles
c.progressSignal.emit(percent)
fileQueue.task_done()
def threadWorkerCopy(self, fileNameList):
if fileQueue.empty():
for i in range(16):
t = threading.Thread(target=self.CopyWorker)
t.daemon = True
t.start()
for fileName in fileNameList:
fileQueue.put(fileName)
fileQueue.join()
def updateProgressBar(self, percent):
self.progressBar.setValue(percent)
我正在尝试从多个线程更新 pyqt QProgressBar，据我所知，最好的方法是将信号发射回主 GUI 线程（我尝试传递 QProgressBar反对工作线程，尽管它似乎确实有效，但我在解释器中收到了大量警告）。在下面的代码中，我设置了一个 progressSignal 信号并将其连接到一个线程（目前）只打印发出的任何内容。然后我从每个线程发出总百分比。我知道这在线程外起作用，只需在第 47 行中抛出一个随机发射，它确实会通过。然而，第 36 行的发射不会触发任何东西，所以它似乎永远不会通过...
import Queue, threading
from PyQt4 import QtCore
import shutil
import profile
fileQueue = Queue.Queue()
class Communicate(QtCore.QObject):
progressSignal = QtCore.pyqtSignal(int)
class ThreadedCopy:
totalFiles = 0
copyCount = 0
lock = threading.Lock()
def __init__(self, inputList, progressBar="Undefined"):
self.totalFiles = len(inputList)
self.c = Communicate()
self.c.progressSignal.connect(self.updateProgressBar)
print str(self.totalFiles) + " files to copy."
self.threadWorkerCopy(inputList)
def CopyWorker(self):
while True:
self.c.progressSignal.emit(2000)
fileName = fileQueue.get()
shutil.copy(fileName[0], fileName[1])
fileQueue.task_done()
with self.lock:
self.copyCount += 1
percent = (self.copyCount * 100) / self.totalFiles
self.c.progressSignal.emit(percent)
def threadWorkerCopy(self, fileNameList):
for i in range(16):
t = threading.Thread(target=self.CopyWorker)
t.daemon = True
t.start()
for fileName in fileNameList:
fileQueue.put(fileName)
fileQueue.join()
self.c.progressSignal.emit(1000)
def updateProgressBar(self, percent):
print percent
更新：
这是带有图形用户界面的示例。这个运行但非常不稳定，它经常崩溃并且 UI 做了一些奇怪的事情（进度条没有完成，等等）
Main.py:
import sys, os
import MultithreadedCopy_5
from PyQt4 import QtCore, QtGui
def grabFiles(path):
# gets all files (not folders) in a directory
for file in os.listdir(path):
if os.path.isfile(os.path.join(path, file)):
yield os.path.join(path, file)
class MainWin(QtGui.QWidget):
def __init__(self):
super(MainWin, self).__init__()
self.initUI()
def initUI(self):
self.progress = QtGui.QProgressBar()
box = QtGui.QVBoxLayout()
box.addWidget(self.progress)
goBtn = QtGui.QPushButton("Start copy")
box.addWidget(goBtn)
self.setLayout(box)
goBtn.clicked.connect(self.startCopy)
def startCopy(self):
files = grabFiles("folder/with/files")
fileList = []
for file in files:
fileList.append([file,"folder/to/copy/to"])
MultithreadedCopy_5.ThreadedCopy(fileList, self.progress)
def main():
app = QtGui.QApplication(sys.argv)
ex = MainWin()
ex.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()
MultithreadedCopy_5.py:
import Queue, threading
from PyQt4 import QtCore
import shutil
import profile
fileQueue = Queue.Queue()
class Communicate(QtCore.QObject):
progressSignal = QtCore.pyqtSignal(int)
class ThreadedCopy:
totalFiles = 0
copyCount = 0
lock = threading.Lock()
def __init__(self, inputList, progressBar="Undefined"):
self.progressBar = progressBar
self.totalFiles = len(inputList)
self.c = Communicate()
self.c.progressSignal.connect(self.updateProgressBar, QtCore.Qt.DirectConnection)
print str(self.totalFiles) + " files to copy."
self.threadWorkerCopy(inputList)
def CopyWorker(self):
while True:
fileName = fileQueue.get()
shutil.copy(fileName[0], fileName[1])
fileQueue.task_done()
with self.lock:
self.copyCount += 1
percent = (self.copyCount * 100) / self.totalFiles
self.c.progressSignal.emit(percent)
def threadWorkerCopy(self, fileNameList):
for i in range(16):
t = threading.Thread(target=self.CopyWorker)
t.daemon = True
t.start()
for fileName in fileNameList:
fileQueue.put(fileName)
fileQueue.join()
def updateProgressBar(self, percent):
self.progressBar.setValue(percent)
#profile.run('ThreadedCopy()')
主要问题是发送信号和接收信号之间的时间延迟，我们可以使用 processEvents():
You can call this function occasionally when your program is busy performing a long operation (e.g. copying a file).
def CopyWorker(self):
while True:
fileName = fileQueue.get()
shutil.copy(fileName[0], fileName[1])
fileQueue.task_done()
with self.lock:
self.copyCount += 1
print(self.copyCount)
percent = (self.copyCount * 100) / self.totalFiles
self.c.progressSignal.emit(percent)
QtCore.QCoreApplication.processEvents()
你的例子有两个主要问题。
首先，发出信号的对象是在 main/gui 线程中创建的，因此它发出的任何信号都不是跨线程的，因此不是线程安全的。显而易见的解决方案是在工作线程的目标函数内部创建信号对象——这意味着每个线程必须有一个单独的实例。
其次，目标函数内的 while 循环永远不会终止，这意味着每个 ThreadedCopy 对象将在当前复制操作完成后保持活动状态。由于所有这些对象共享同一个队列，如果试图重复复制操作，行为将变得不可预测。显而易见的解决方案是一旦队列为空就跳出 while 循环。
下面是 MultithreadedCopy_5.py 的重写，应该可以解决这些问题。但是，如评论中所述，我仍然强烈建议在这种情况下使用 QThread 而不是 python 线程，因为它可能会提供更强大且更易于维护的解决方案。
import Queue, threading
from PyQt4 import QtCore
import shutil
import profile
fileQueue = Queue.Queue()
class Communicate(QtCore.QObject):
progressSignal = QtCore.pyqtSignal(int)
class ThreadedCopy:
totalFiles = 0
copyCount = 0
lock = threading.Lock()
def __init__(self, inputList, progressBar="Undefined"):
self.progressBar = progressBar
self.totalFiles = len(inputList)
print str(self.totalFiles) + " files to copy."
self.threadWorkerCopy(inputList)
def CopyWorker(self):
c = Communicate()
c.progressSignal.connect(self.updateProgressBar)
while True:
try:
fileName = fileQueue.get(False)
except Queue.Empty:
break
else:
shutil.copy(fileName[0], fileName[1])
with self.lock:
self.copyCount += 1
percent = (self.copyCount * 100) / self.totalFiles
c.progressSignal.emit(percent)
fileQueue.task_done()
def threadWorkerCopy(self, fileNameList):
if fileQueue.empty():
for i in range(16):
t = threading.Thread(target=self.CopyWorker)
t.daemon = True
t.start()
for fileName in fileNameList:
fileQueue.put(fileName)
fileQueue.join()
def updateProgressBar(self, percent):
self.progressBar.setValue(percent)