使用 moveToThread 在 PyQt5 中启动 QThreads。一个线程无法正常启动

Question

我在下面的（半）工作示例中有 4 个工作线程。我只能让前三个工作线程工作。如何让第 4 个线程到达运行？

print(QThread.idealThreadCount()) returns '8' 在我的笔记本电脑上。

我可以对代码重新排序以组成 3 个工人的任意组合运行。

from PyQt5.QtCore import QThread, QObject
from PyQt5.QtWidgets import QWidget
import sys
from PyQt5.QtWidgets import QApplication
import time

class A(QObject):
    def run(self):
        while 1:
            print('A', time.ctime())
            time.sleep(1)
class B(QObject):
    def run(self):
        while 1:
            print('B', time.ctime())
            time.sleep(1)
class C(QObject):
    def run(self):
        while 1:
            print('C', time.ctime())
            time.sleep(1)
class D(QObject):
    def run(self):
        while 1:
            print('D', time.ctime())
            time.sleep(1)

class window1(QWidget):
    def __init__ (self, parent = None):
        super().__init__ () #parent widget
        print(QThread.idealThreadCount())

        self.thread1 = QThread()
        obj1 = A()
        obj1.moveToThread(self.thread1)
        self.thread1.started.connect(obj1.run)
        self.thread1.start()

        self.thread2 = QThread()
        obj2 = B()
        obj2.moveToThread(self.thread2)
        self.thread2.started.connect(obj2.run) 
        self.thread2.start()

        self.thread3 = QThread()
        obj3 = C()
        obj3.moveToThread(self.thread3)
        self.thread3.started.connect(obj3.run)
        self.thread3.start()

        self.thread4 = QThread()
        obj4 = D()
        obj4.moveToThread(self.thread4)
        self.thread4.started.connect(obj4.run)
        self.thread4.start()

app = QApplication(sys.argv) 
w = window1()
w.show()
sys.exit(app.exec_())

Answer 1

我发现如果我在 __init__ 方法的最后添加一个 time.sleep(1) 延迟，所有线程现在都可以工作....

不过我想明白为什么。更好的答案将不胜感激。

from PyQt5.QtCore import QThread, QObject
from PyQt5.QtWidgets import QWidget, QApplication
import sys
import time

class A(QObject):
    def run(self):
        while 1:
            print('A', time.ctime())
            time.sleep(1)
class B(QObject):
    def run(self):
        while 1:
            print('B', time.ctime())
            time.sleep(1)
class C(QObject):
    def run(self):
        while 1:
            print('C', time.ctime())
            time.sleep(1)
class D(QObject):
    def run(self):
        while 1:
            print('D', time.ctime())
            time.sleep(1)

class window1(QWidget):
    def __init__ (self, parent = None):
        super().__init__ () #parent widget

        self.thread1 = QThread()
        obj1 = A()
        obj1.moveToThread(self.thread1)
        self.thread1.started.connect(obj1.run)
        self.thread1.start()

        self.thread2 = QThread()
        obj2 = B()
        obj2.moveToThread(self.thread2)
        self.thread2.started.connect(obj2.run) #this sets up a signal in the other direction??
        self.thread2.start()

        self.thread3 = QThread()
        obj3 = C()
        obj3.moveToThread(self.thread3)
        self.thread3.started.connect(obj3.run) #this sets up a signal in the other direction??
        self.thread3.start()

        self.thread4 = QThread()
        obj4 = D()
        obj4.moveToThread(self.thread4)
        self.thread4.started.connect(obj4.run)
        self.thread4.start()

        time.sleep(1)

app = QApplication(sys.argv) #every pyqt application must create an application object
w = window1()
w.show()
sys.exit(app.exec_())

Answer 2

您没有存储对 obj1、obj2 等的引用。因为它们没有父级（使用 moveToThread 需要父级），它们最终会被垃圾回收__init__ 方法。您添加的 time.sleep(1) 只是延迟了 __init__ 方法和垃圾收集的结束。

如果您存储对对象的引用（例如 self.obj1 = ...），那么您的所有线程都应该运行正确。

使用 moveToThread 在 PyQt5 中启动 QThreads。一个线程无法正常启动

Launching QThreads in PyQt5 using moveToThread. One thread fails to launch properly

python

multithreading

pyqt

qthread

pyqt5