Question

在这个简单的PyQt演示程序中，我从主线程发出信号。在工作线程中，我连接到它们，但信号处理程序在主线程中运行：

from PyQt4 import QtGui, QtCore
import threading
from time import sleep
import sys


class Data():
    def __init__(self, a, b):
        self.a = a
        self.b = b

    def __str__(self):
        return "Data having %d and %d" % (self.a, self.b)

class Worker(QtCore.QThread):
    def __init__(self, parent):
        QtCore.QThread.__init__(self)
        self.p = parent

    def run(self):
        self.connect(self.p, QtCore.SIGNAL("newTask"), self.task)
        print "[%s] running exec_()" % threading.currentThread()
        self.exec_()

    def task(self, dataobj):
        print "[%s] Processing" % threading.currentThread(), dataobj
        sleep(3)
        print "Done with", dataobj
        self.emit(QtCore.SIGNAL("taskDone"), str(dataobj))

class App(QtCore.QObject):
    def __init__(self):
        QtCore.QObject.__init__(self)
        self.w = Worker(self)
        self.connect(self.w, QtCore.SIGNAL("taskDone"), self.on_task_done)
        self.w.start()

    def assign_tasks(self):
        self.emit(QtCore.SIGNAL("newTask"), Data(3, 4))
        self.emit(QtCore.SIGNAL("newTask"), Data(5, 6))
        print "[%s] Tasks sent" % threading.currentThread()

    @staticmethod
    def on_task_done(objstr):
        print "[%s] App: Worker finished with" % threading.currentThread(), objstr

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    a = App()
    sleep(1)
    a.assign_tasks()
    sleep(20)
    sys.exit(app.exec_())

但结果显示回调是在主线程中运行的：

[<_DummyThread(Dummy-1, started daemon 105564)>] running exec_()
[<_MainThread(MainThread, started 105612)>] Processing Data having 3 and 4
Done with Data having 3 and 4
[<_MainThread(MainThread, started 105612)>] App: Worker finished with Data having 3 and 4
[<_MainThread(MainThread, started 105612)>] Processing Data having 5 and 6
Done with Data having 5 and 6
[<_MainThread(MainThread, started 105612)>] App: Worker finished with Data having 5 and 6
[<_MainThread(MainThread, started 105612)>] Tasks sent

我做错了什么？不幸的是，关于这个的PyQt文档是非常不完整和矛盾的。

如果我使用moveToThread技术，我会得到类似的结果：

from PyQt4 import QtGui, QtCore
import threading
from time import sleep
import sys

class Data():
    def __init__(self, a, b):
        self.a = a
        self.b = b

    def __str__(self):
        return "Data having %d and %d" % (self.a, self.b)

class Worker(QtCore.QObject):
    def __init__(self, parent):
        QtCore.QObject.__init__(self)
        self.connect(parent, QtCore.SIGNAL("newTask"), self.task)

    def task(self, dataobj):
        print "[%s] Processing" % threading.currentThread(), dataobj
        sleep(3)
        print "Done with", dataobj
        self.emit(QtCore.SIGNAL("taskDone"), str(dataobj))

    def start(self):
        print "[%s] start()" % threading.currentThread()

class App(QtCore.QObject):
    def __init__(self):
        QtCore.QObject.__init__(self)

        self.w = Worker(self)
        self.t = QtCore.QThread(self)
        self.w.moveToThread(self.t)
        self.connect(self.w, QtCore.SIGNAL("taskDone"), self.on_task_done)
        self.connect(self.t, QtCore.SIGNAL("started()"), self.w.start)
        self.t.start()

    def assign_tasks(self):
        self.emit(QtCore.SIGNAL("newTask"), Data(3, 4))
        self.emit(QtCore.SIGNAL("newTask"), Data(5, 6))
        print "[%s] Tasks sent" % threading.currentThread()

    @staticmethod
    def on_task_done(objstr):
        print "[%s] App: Worker finished with" % threading.currentThread(), objstr

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    a = App()
    sleep(1)
    a.assign_tasks()
    sleep(20)
    sys.exit(app.exec_())

结果是：

[<_DummyThread(Dummy-1, started daemon 108992)>] start()
[<_MainThread(MainThread, started 107004)>] Processing Data having 3 and 4
Done with Data having 3 and 4
[<_MainThread(MainThread, started 107004)>] App: Worker finished with Data having 3 and 4
[<_MainThread(MainThread, started 107004)>] Processing Data having 5 and 6
Done with Data having 5 and 6
[<_MainThread(MainThread, started 107004)>] App: Worker finished with Data having 5 and 6
[<_MainThread(MainThread, started 107004)>] Tasks sent

Answer 1

您的Worker个对象＆＃39;直播＆＃39;在主线程中，这意味着它们的所有信号都将由主线程的事件循环处理。这些对象QThread s的事实并没有改变它。

如果您希望信号由不同的线程处理，您首先需要使用它的moveToThread方法将worker对象移动到该线程。

因此，在您的情况下，只有run方法在另一个线程中执行，task方法仍在主线程中执行。改变这种情况的方法是：

让您的Worker成为常规QObject，而不是QThread
在QThread中创建App，启动它并将工作人员移至该线程
然后将信号发送给工人，使其开始处理

你应该查看这些参考资料：

编辑：

我在代码中注意到的其他一些事情：

你正在混合python线程和qt线程。 threading.currentThread将不正确反映当前的qt线程。请使用QThread.currentThread()。
装饰您正在调用pyqtSlots的广告位，不这样做可能会导致此类问题。
使用new style signals。 PyQt5不再支持旧式信号，新风格的信号更容易使用。

所以这是一个应该有效的代码版本：

from PyQt4 import QtGui, QtCore
import threading
from time import sleep
import sys

class Data():
    def __init__(self, a, b):
        self.a = a
        self.b = b

    def __str__(self):
        return "Data having %d and %d" % (self.a, self.b)

class Worker(QtCore.QObject):

    taskDone = QtCore.pyqtSignal(str)

    def __init__(self, parent):
        QtCore.QObject.__init__(self)
        parent.newTask.connect(self.task)

    @QtCore.pyqtSlot(object)
    def task(self, dataobj):
        print "[%s] Processing" % QtCore.QThread.currentThread().objectName(), dataobj
        sleep(3)
        print "Done with", dataobj
        self.taskDone.emit(str(dataobj))

    @QtCore.pyqtSlot()
    def start(self):
        print "[%s] start()" % QtCore.QThread.currentThread().objectName()

class App(QtCore.QObject):

    newTask = QtCore.pyqtSignal(object)

    def __init__(self):
        QtCore.QObject.__init__(self)
        self.w = Worker(self)
        self.t = QtCore.QThread(self, objectName='workerThread')
        self.w.moveToThread(self.t)
        self.w.taskDone.connect(self.on_task_done)
        self.t.started.connect(self.w.start)
        self.t.start()

    def assign_tasks(self):
        self.newTask.emit(Data(3, 4))
        self.newTask.emit(Data(5, 6))
        print "[%s] Tasks sent" % QtCore.QThread.currentThread().objectName()

    @staticmethod
    def on_task_done(objstr):
        print "[%s] App: Worker finished with" % QtCore.QThread.currentThread().objectName(), objstr

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    QtCore.QThread.currentThread().setObjectName('main')
    a = App()
    sleep(1)
    a.assign_tasks()
    from utils import sigint
    sys.exit(app.exec_())

我已经设置了线程objectName以使输出更易读：

[workerThread] start()
[main] Tasks sent
[workerThread] Processing Data having 3 and 4
Done with Data having 3 and 4
[workerThread] Processing Data having 5 and 6
[main] App: Worker finished with Data having 3 and 4
Done with Data having 5 and 6
[main] App: Worker finished with Data having 5 and 6

PyQt |信号未在QThread中处理，但在主线程中处理

1 个答案: