PyQt, QThread, GIL, 图形界面

Question

我有一个用Python写的图形界面和程序逻辑。我经常通过调用 urllib.requests 来请求网络信息，这导致图形界面变得无响应，尽管这些调用是用 QThread 包裹的。我觉得这可能是因为 GIL 的原因。但是，如果我在PyQt应用中使用 QThread，那么它的作用是什么呢？如果我不能让代码异步运行的话。

--代码--

qtthreaddecorator.py:

from PyQt4 import QtCore

class Worker(QtCore.QThread):
    def __init__(self, thread_name, finished_slot, function, *args, **kwargs):
        QtCore.QThread.__init__(self)

        self._thread_name = thread_name
        self._function = function
        self._args = args
        self._kwargs = kwargs

        self._finished_slot = finished_slot

    def run(self):
        self._function(*self._args, **self._kwargs)

        self._finished_slot()

        return

def qt_thread_decorator(slot):
    def decorator(function):
        def wrapper(*args, **kwargs):
            worker = Worker(function.__name__, slot, function, *args, **kwargs)
            worker.start()

            return
        return wrapper
    return decorator

我使用它的地方是：

import qtthreaddecorator

class MainWindow(QtGui.QMainWindow, form_class):

def __init__(self, parent=None):
    QtGui.QMainWindow.__init__(self, parent)
    self.setupUi(self)

    self.init()

def init(self):
    @qtthreaddecorator.qt_thread_decorator(self._fill_servers)
    def _get_servers():
        self._get_my_servers()
    @qtthreaddecorator.qt_thread_decorator(self._fill_user_info)
    def _get_user_info():
        self._get_user_info()

    _get_servers()
    _get_user_info()

在我的情况下，_get_servers() 和 _get_user_info() 是顺序调用的，但我想让它们同时执行。

Answer 1

虽然这个问题的解决方案已经由Fenikso提供，但用装饰器来解决这个问题也很有意思。

我已经把我的qtthreaddecorator.py修改成了以下内容：

from PyQt4 import QtCore


class Worker(QtCore.QThread):
    threads = []

    def __init__(self, thread_name, function, *args, **kwargs):
        QtCore.QThread.__init__(self)

        self._thread_name = thread_name
        self._function = function
        self._args = args
        self._kwargs = kwargs

    def run(self):
        Worker.threads.append(self.currentThreadId())            
        self._function(*self._args, **self._kwargs)
        self.emit(QtCore.SIGNAL('finished()'))
        Worker.threads.remove(self.currentThreadId())


def qt_thread_decorator():
    def decorator(function):
        def wrapper(*args, **kwargs):
            worker = Worker(function.__name__, function, *args, **kwargs)

            def on_finish():
                worker.quit()

            worker.finished.connect(on_finish)
            worker.start()

            return worker
        return wrapper
    return decorator

然后在使用这个装饰器的代码中：

import qtthreaddecorator

class MainWindow(QtGui.QMainWindow, form_class):

    def __init__(self, parent=None):
        QtGui.QMainWindow.__init__(self, parent)
        self.setupUi(self)

        self.init()

    def init(self):
        @qtthreaddecorator.qt_thread_decorator()
        def _get_servers():
            self._get_my_servers()
        @qtthreaddecorator.qt_thread_decorator()
        def _get_user_info():
            self._get_user_info()

        _get_servers().finished.connect(self._fill_servers)
        _get_user_info().finished.connect(self._fill_user_info)

Answer 2

我觉得你在使用装饰器的时候把事情搞得太复杂了。其实你只需要大约3到4行代码，就能轻松地把你的代码放到一个新线程里。而且，我认为你不应该直接从另一个线程里调用你完成的槽函数。你应该使用一个连接的信号来激活它。

import sys
from time import sleep
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *

class Signals(QObject):
    update = pyqtSignal(int)
    enable_button = pyqtSignal(bool)

class Window(QWidget):
    def __init__(self, *args, **kwargs):
        QWidget.__init__(self, *args, **kwargs)

        self.button = QPushButton("Run", self)
        self.button.clicked.connect(self.onButton)

        self.progress = QProgressBar(self)
        self.progress.setTextVisible(False)

        self.layout = QVBoxLayout()
        self.layout.setContentsMargins(5, 5, 5, 5)
        self.layout.addWidget(self.button)
        self.layout.addWidget(self.progress)
        self.layout.addStretch()

        self.worker_thread = QThread()
        self.worker_thread.run = self.worker
        self.worker_thread.should_close = False

        self.signals = Signals()
        self.signals.update.connect(self.progress.setValue)
        self.signals.enable_button.connect(self.button.setEnabled)

        self.setLayout(self.layout)
        self.show()
        self.resize(self.size().width(), 0)

    # Override
    def closeEvent(self, e):
        self.worker_thread.should_close = True
        self.worker_thread.wait()

    @pyqtSlot()
    def onButton(self):
        self.button.setDisabled(True)
        self.worker_thread.start()

    # Worker thread, no direct GUI updates!
    def worker(self):
        for i in range(101):
            if self.worker_thread.should_close:
                break
            self.signals.update.emit(i)
            sleep(0.1)
        self.signals.enable_button.emit(True)

app = QApplication(sys.argv)
win = Window()
sys.exit(app.exec_())