首页 / 问题 / 正文

从PyQt线程内部启动多个线程

2 投票
1 回答
5490 浏览
提问于 2025-04-18 04:52

我现在有一个脚本，可以读取一个文件夹里的文件（有成千上万个文件），然后把这些文件放到一个列表里，再分成4个小列表。接着，我为每个小列表运行一个线程。这在Python脚本中实现起来非常简单。

thread1fileList, thread2fileList, thread3fileList, thread4fileList = load.sortFiles(fileList)
threads = [threading.Thread(target=load.threadLoad, args=(fileList, ))
for fileList in (thread1fileList, thread2fileList, thread3fileList, thread4fileList)]
for thread in threads:
    thread.start()
for thread in threads:
    thread.join()

不过，我现在把这段代码移到一个图形用户界面（GUI）上，使用的是Pyside。

我已经能够创建一个线程来读取文件夹里的文件（这样可以确保GUI在运行时不会卡住），但是我无法在Qt.Thread里面启动4个新线程来处理文件列表。

这是我的核心代码

self.unzipThread = UnzipThread()
self.unzipThread.start()
self.unzipThread.finished.connect(self.finishUp()) #finsihUp provides the final page of the wizard


class UnzipThread(QtCore.QThread):
    def __init__(self):
        QtCore.QThread.__init__(self)

    def run(self):
        for dirname, dirnames, filenames in os.walk(directorypath):
            for filename in filenames:
                if filename.endswith(".zip"):
                   fileList.append(filename)
                   count = count +1

如果我尝试在运行函数中添加启动线程的代码，就会出现一个错误，提示这是不被允许的。

那我该怎么做才能实现这个功能呢？

谢谢

编辑##

完整示例

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

import sys
from PySide import QtGui, QtCore
import os

class Example(QtGui.QWidget):

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

    self.initUI()

def initUI(self):

    runButton = QtGui.QPushButton("Run")
    runButton.clicked.connect(self.unzip)
    exitButton = QtGui.QPushButton("Exit")
    exitButton.clicked.connect(QtCore.QCoreApplication.instance().quit)
    hbox = QtGui.QHBoxLayout()
    hbox.addWidget(runButton)
    hbox.addStretch(1)
    hbox.addWidget(exitButton)
    titleBox = QtGui.QVBoxLayout()
    titleLabel = QtGui.QLabel(self.tr("Find Zip File"))

    searchBox = QtGui.QHBoxLayout()
    self.fileLabel = QtGui.QLabel(self.tr("Location: "))
    self.fileLineEdit = QtGui.QLineEdit()
    self.fileDialogBtn =  QtGui.QPushButton("Browse")
    self.fileDialogBtn.clicked.connect(self.openDirectoryDialog)
    searchBox.addWidget(self.fileLabel)
    searchBox.addWidget(self.fileLineEdit)
    searchBox.addWidget(self.fileDialogBtn)

    titleBox.addWidget(titleLabel)
    titleBox.addStretch(1)
    titleBox.addLayout(searchBox)
    titleBox.addStretch(1)
    titleBox.addLayout(hbox)

    self.setLayout(titleBox)

    self.resize(500, 300)
    self.center()
    self.setWindowTitle('Example')
    self.show()

def unzip(self):
    self.unzipThread = UnzipThread(self.filePath)
    self.unzipThread.start()
    self.unzipThread.finished.connect(self.finishUp)

def openDirectoryDialog(self):
    flags = QtGui.QFileDialog.DontResolveSymlinks | QtGui.QFileDialog.ShowDirsOnly
    directory = QtGui.QFileDialog.getExistingDirectory(self, "Open Directory", os.getcwd(),flags)
    self.fileLineEdit.setText(directory)
    self.filePath = self.fileLineEdit.text()

def center(self):
    qr = self.frameGeometry()
    cp = QtGui.QDesktopWidget().availableGeometry().center()
    qr.moveCenter(cp)
    self.move(qr.topLeft())

def closeEvent(self, event):
    reply = QtGui.QMessageBox.question(self, 'Message',
        "Are you sure to quit?", QtGui.QMessageBox.Yes |
        QtGui.QMessageBox.No, QtGui.QMessageBox.No)

    if reply == QtGui.QMessageBox.Yes:
        event.accept()
    else:
        event.ignore()

def finishUp(self):#yet to code up to GUI log windows
    print "finished"

class UnzipThread(QtCore.QThread):
def __init__(self, filepath):
    QtCore.QThread.__init__(self)

    self.filePath = filepath

def run(self):
    fileList = []
    count = 0
    for dirname, dirnames, filenames in os.walk(self.filePath):
        for filename in filenames:
            if filename.endswith(".shp"):
                fileList.append(filename)
                count += 1
    print count

    list1 = []
    list2 = []

    for shpfile in fileList:
        if "line" in shpfile:
            list1.append(shpfile)
        elif "point" in shpfile:
            list2.append(shpfile)
        else:
            pass

    self.processThread1 = ProcessThread1(list1)
    self.processThread1.start()
    self.processThread1.finished.connect(self.threadCount)

    self.processThread2 = ProcessThread2(list2)
    self.processThread2.start()
    self.processThread2.finished.connect(self.threadCount)

    return

def threadCount(self):
    print "got here"

class ProcessThread1(QtCore.QThread):
def __init__(self, filelist):
    QtCore.QThread.__init__(self)

    self.filelist = filelist

def run(self):
    count = 0
    for textfile in self.filelist:
        count +=1

    print "thread 1 count %s" %(count)

    return

class ProcessThread2(QtCore.QThread):
def __init__(self, filelist):
    QtCore.QThread.__init__(self)

    self.filelist = filelist

def run(self):
    count = 0
    for textfile in self.filelist:
        count +=1

    print "thread 2 count %s" %(count)

    return

def main():

app = QtGui.QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())


if __name__ == '__main__':
    main()

在我删掉很多代码以提供这个示例后，发现从我的QT.Thread内部运行线程是可以的，但初始线程在其他线程还没完成之前就认为自己已经结束了。

所以我得到的结果是这样的：

5635

finishedthread 1 count 2858

thread 2 count 2777here

here

你可以看到“finished”这个评论出现在其他代码“thread count 1”等之前，这证明它认为自己已经完成了。

那么，有什么办法让它们之间进行沟通吗？

谢谢

编辑 2

现在我已经把代码改成使用QObjects和movetoThread，但我该如何正确判断两个子线程是否都已经完成呢？这是我现在的代码。我不得不使用一个线程计数器和一个While循环来判断两个子线程是否都完成了。难道没有更好的方法吗？

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

import sys
from PySide import QtGui, QtCore
import os
from PySide.QtCore import Signal as pyqtSignal
import time

class Example(QtGui.QWidget):

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

        self.initUI()

    def initUI(self):

        runButton = QtGui.QPushButton("Run")
        runButton.clicked.connect(self.unzip)
        exitButton = QtGui.QPushButton("Exit")
        exitButton.clicked.connect(QtCore.QCoreApplication.instance().quit)
        hbox = QtGui.QHBoxLayout()
        hbox.addWidget(runButton)
        hbox.addStretch(1)
        hbox.addWidget(exitButton)
        titleBox = QtGui.QVBoxLayout()
        titleLabel = QtGui.QLabel(self.tr("Find Zip File"))

        searchBox = QtGui.QHBoxLayout()
        self.fileLabel = QtGui.QLabel(self.tr("Location: "))
        self.fileLineEdit = QtGui.QLineEdit()
        self.fileDialogBtn =  QtGui.QPushButton("Browse")
        self.fileDialogBtn.clicked.connect(self.openDirectoryDialog)
        searchBox.addWidget(self.fileLabel)
        searchBox.addWidget(self.fileLineEdit)
        searchBox.addWidget(self.fileDialogBtn)

        titleBox.addWidget(titleLabel)
        titleBox.addStretch(1)
        titleBox.addLayout(searchBox)
        titleBox.addStretch(1)
        titleBox.addLayout(hbox)

        self.setLayout(titleBox)

        self.resize(500, 300)
        self.center()
        self.setWindowTitle('Example')
        self.show()

    def unzip(self):
        thread = self.thread = QtCore.QThread()
        worker = self.worker = Worker(self.filePath)
        worker.moveToThread(thread)
        worker.finished.connect(worker.deleteLater)
        worker.finished.connect(thread.quit)
        thread.started.connect(worker.run)
        thread.finished.connect(self.finishUp)
        thread.start()

    def openDirectoryDialog(self):
        flags = QtGui.QFileDialog.DontResolveSymlinks | QtGui.QFileDialog.ShowDirsOnly
        directory = QtGui.QFileDialog.getExistingDirectory(self, "Open Directory", os.getcwd(),flags)
        self.fileLineEdit.setText(directory)
        self.filePath = self.fileLineEdit.text()

    def center(self):
        qr = self.frameGeometry()
        cp = QtGui.QDesktopWidget().availableGeometry().center()
        qr.moveCenter(cp)
        self.move(qr.topLeft())

    def closeEvent(self, event):
        reply = QtGui.QMessageBox.question(self, 'Message',
            "Are you sure to quit?", QtGui.QMessageBox.Yes |
            QtGui.QMessageBox.No, QtGui.QMessageBox.No)

        if reply == QtGui.QMessageBox.Yes:
            event.accept()
        else:
            event.ignore()

    def finishUp(self):#yet to code up to GUI log windows
        print "unzip thread finished"

class Worker(QtCore.QObject):
    finished = pyqtSignal()

    def __init__(self, filepath):
        QtCore.QObject.__init__(self)

        self.filePath = filepath

    def run(self):
        self.threadcount = 0
        print "finding files"
        fileList = []
        count = 0
        for dirname, dirnames, filenames in os.walk(self.filePath):
            for filename in filenames:
                if filename.endswith(".shp"):
                    fileList.append(filename)
                    count += 1
        print count

        self.list1 = []
        self.list2 = []

        for shpfile in fileList:
            if "line" in shpfile:
                self.list1.append(shpfile)
            elif "point" in shpfile:
                self.list2.append(shpfile)
            else:
                pass

        thread1 = self.thread1 = QtCore.QThread()
        worker1 = self.worker1 = Process1(self.list1)
        worker1.moveToThread(thread1)
        worker1.finished.connect(worker1.deleteLater)
        worker1.finished.connect(thread1.quit)
        thread1.started.connect(worker1.run)
        thread1.finished.connect(self.finishUp)
        thread1.start()


        thread2 = self.thread2 = QtCore.QThread()
        worker2 = self.worker2 = Process2(self.list2)
        worker2.moveToThread(thread2)
        worker2.finished.connect(worker2.deleteLater)
        worker2.finished.connect(thread2.quit)
        thread2.started.connect(worker2.run)
        thread2.finished.connect(self.finishUp)
        thread2.start()

    def finishUp(self):
        self.threadcount += 1
        while True:
            if self.threadcount != 2:
                break
            else:
                print "extra threads finished"
                self.finished.emit()
                break


class Process1(QtCore.QObject):
    finished = pyqtSignal()
    def __init__(self, filelist):
        QtCore.QObject.__init__(self)

        self.filelist = filelist

    def run(self):
        count = 0
        for textfile in self.filelist:
            count +=1

        print "thread 1 count %s" %(count)

        self.finished.emit()


class Process2(QtCore.QObject):
    finished = pyqtSignal()
    def __init__(self, filelist):
        QtCore.QObject.__init__(self)

        self.filelist = filelist

    def run(self):
        count = 0
        for textfile in self.filelist:
            count +=1

        time.sleep(15)

        print "thread 2 count %s" %(count)

        self.finished.emit()

def main():

    app = QtGui.QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()
多线程 gui 线程管理 qt pyside 线程通信 QObject 线程计数器

1 个回答

1

首先，"finished"这个提示出现在"thread count x"之前，是因为UnzipThread确实在ProcessingThreads之前就完成了。这是正常的情况。

其次，我不能确定是否存在通信问题，但你最好了解一下QThreads的正确使用方法。不推荐直接继承QThread，因为这样会导致信号传递的问题。更好的做法是使用工作对象，并通过QObject:movetoThread()把它们移动到线程中。

如果你还有疑问，可以在所有可能的地方打印QThread.currentThread()，看看实际是哪个线程在运行什么代码。

回答于 2025-04-18 由 Python大师
分享 举报

撰写回答