qt - PyQt:通过信号中断qthread

Question

我是 pyqt 的新手，所以我希望我尝试做的事情不会有任何奇怪的地方。我试图通过使用 PyQt 信号在 QThreads 之间创建交互。特别是，我想做的是从一个线程发出一个信号，这个信号应该中断线程正在做的事情来运行一个特定的方法。顺便说一下，我在这样做时遇到了一些问题，所以我想知道我尝试做的事情是否合法。

例如，现在我正在尝试做这样的事情:

import sys
import time
from PyQt4 import QtGui as qt
from PyQt4 import QtCore as qtcore
from PyQt4.QtCore import QThread
import threading

app = qt.QApplication(sys.argv)
class widget(qt.QWidget):

    def __init__(self, parent=None):
        qtcore.QObject.__init__(self)


    def appinit(self):
        self.mysignal = qtcore.SIGNAL("mysignal")
        thread = mythread(self)
        thread.start()
        time.sleep(5)
        print "before emit",str(threading.current_thread())
        self.emit(self.mysignal,"hello, I'm thread "+str(threading.current_thread()))
        print "after emit",str(threading.current_thread())



class mythread(QThread):
    def __init__(self,parent):
        qtcore.QThread.__init__(self, parent=app)
        self.parent=parent

    def run(self):
        self.mysignal = qtcore.SIGNAL("mysignal")
        self.connect(self.parent, self.mysignal, self.myfunc)
        for i in range(15):
            print "**",threading.current_thread(),i
            time.sleep(1)

    def myfunc(self, msg):
        print threading.current_thread(), msg, "Enter"
        time.sleep(5)
        print threading.current_thread(), msg, "Exit"


def main():
    mywidget = widget()
    mywidget.show()
    qtcore.QTimer.singleShot(0, mywidget.appinit)
    sys.exit(app.exec_())

main()

我得到的输出是:

** <_DummyThread(Dummy-1, started daemon 1968)> 0
** <_DummyThread(Dummy-1, started daemon 1968)> 1
** <_DummyThread(Dummy-1, started daemon 1968)> 2
** <_DummyThread(Dummy-1, started daemon 1968)> 3
** <_DummyThread(Dummy-1, started daemon 1968)> 4
before emit <_MainThread(MainThread, started 2928)>
<_MainThread(MainThread, started 2928)> hello, I'm thread <_MainThread(MainThread, started 2928)> Enter
** <_DummyThread(Dummy-1, started daemon 1968)> 5
** <_DummyThread(Dummy-1, started daemon 1968)> 6
** <_DummyThread(Dummy-1, started daemon 1968)> 7
** <_DummyThread(Dummy-1, started daemon 1968)> 8
** <_DummyThread(Dummy-1, started daemon 1968)> 9
<_MainThread(MainThread, started 2928)> hello, I'm thread <_MainThread(MainThread, started 2928)> Exit
after emit <_MainThread(MainThread, started 2928)>
** <_DummyThread(Dummy-1, started daemon 1968)> 10
** <_DummyThread(Dummy-1, started daemon 1968)> 11
** <_DummyThread(Dummy-1, started daemon 1968)> 12
** <_DummyThread(Dummy-1, started daemon 1968)> 13
** <_DummyThread(Dummy-1, started daemon 1968)> 14

我实际上希望 mythread 中断它的执行并运行 myfunc。顺便说一句，mythread不会中断它的执行，函数myfunc实际上是由主线程运行的。我尝试执行相反的操作(生成的线程向主线程发送信号)并且成功了。

我想我还没有完全理解信号是如何工作的，以及是否可以做我想做的事情。有什么线索吗？我在网上寻找解决方案，但没有结果。

谢谢

Answer 1

好的，据我所知，您希望线程在进一步迭代之前进入 5 秒 sleep 。

import sys
import time
from PyQt4 import QtGui as qt
from PyQt4 import QtCore as qtcore
from PyQt4.QtCore import QThread
import threading

app = qt.QApplication(sys.argv)
class widget(qt.QWidget):

    def __init__(self, parent=None):
        qtcore.QObject.__init__(self)


    def appinit(self):
        self.mysignal = qtcore.SIGNAL("mysignal")
        thread = mythread(self,self.mysignal)
        thread.start()
        time.sleep(5)
        print "before emit",str(threading.current_thread())
        self.emit(self.mysignal,"hello, I'm thread "+str(threading.current_thread()))
        print "after emit",str(threading.current_thread())



class mythread(QThread):
    def __init__(self,parent,sig):
        qtcore.QThread.__init__(self, parent=app)
        self.parent=parent
        self.mysignal = sig
        self.stop_event=threading.Event()
        self.connect(self.parent, self.mysignal, self.setIt)

    def run(self):

        for i in range(15):
            if self.stop_event.isSet():
                self.myfunc()
            print "**",threading.current_thread(),i
            time.sleep(1)

    def setIt(self,msg):
        self.stop_event.set()
        self.msg = msg

    def myfunc(self):
        print threading.current_thread(),self.msg ,  "Enter"
        time.sleep(5)
        print threading.current_thread(),self.msg ,  "Exit"
        self.stop_event.clear()


def main():
    mywidget = widget()
    mywidget.show()
    qtcore.QTimer.singleShot(0, mywidget.appinit)
    sys.exit(app.exec_())

main()

输出:

** <_DummyThread(Dummy-1, started daemon 7312)> 0
** <_DummyThread(Dummy-1, started daemon 7312)> 1
** <_DummyThread(Dummy-1, started daemon 7312)> 2
** <_DummyThread(Dummy-1, started daemon 7312)> 3
** <_DummyThread(Dummy-1, started daemon 7312)> 4
before emit <_MainThread(MainThread, started 232)>
after emit <_MainThread(MainThread, started 232)>
<_DummyThread(Dummy-1, started daemon 7312)> hello, I'm thread <_MainThread(MainThread,     started 232)> Enter
<_DummyThread(Dummy-1, started daemon 7312)> hello, I'm thread <_MainThread(MainThread,     started 232)> Exit
** <_DummyThread(Dummy-1, started daemon 7312)> 5
** <_DummyThread(Dummy-1, started daemon 7312)> 6
** <_DummyThread(Dummy-1, started daemon 7312)> 7
** <_DummyThread(Dummy-1, started daemon 7312)> 8
** <_DummyThread(Dummy-1, started daemon 7312)> 9
** <_DummyThread(Dummy-1, started daemon 7312)> 10
** <_DummyThread(Dummy-1, started daemon 7312)> 11
** <_DummyThread(Dummy-1, started daemon 7312)> 12
** <_DummyThread(Dummy-1, started daemon 7312)> 13
** <_DummyThread(Dummy-1, started daemon 7312)> 14