multithreading - 循环时更新PyQt4 GUI

Question

我想在我的GUI中显示计算进度。为此，我希望每次进行计算时都更新我的PyQt4标签。我知道我应该使用线程来执行此操作，但这是行不通的。没有任何变化，并且while循环完成后，标签将更新为“100％”。即使线程正在工作，该值仍然不会平滑更新。我的代码中有注释，说明什么是什么。请帮我 :)

from PyQt4 import QtGui, QtCore
import time

class MyThread(QtCore.QThread):
    trigger = QtCore.pyqtSignal(int)
    def __init__(self, progress, parent=None):
        super(MyThread, self).__init__(parent)
        self.progress = progress #progress is a PyQt4 label object

    def update_progress(self, value):
        self.progress.setText(QtGui.QApplication.translate("Dialog", "Progress: %s " % value, None))
        print "I was called", value
        print self.progress #prints <PyQt4.QtGui.QLabel object at 0x0000000008151708>
        #as you can see the object is passed all right
    def run(self, value):
        self.trigger.emit(value)

class Calculus:
    def __init__(self):
        print "object created"

    @staticmethod
    def euler(b,h,progress):    
        #progress is a PyQt4 label object, b and h are some integers
        actions_done = 0
        actions_number = b / h

        thread = MyThread(progress)#create a thread
        thread.trigger.connect(thread.update_progress)#connect it with a update function
        thread.start()#start the thread


        while t <= b:
            actions_done+=1
            progress_value = (actions_done/actions_number)*100

            thread.run(progress_value)#emit signal?
            t += h

        thread.terminate()

@EDIT，这是我的解决方案，但存在内存泄漏问题

from PyQt4 import QtGui

class Calculus:
    def __init__(self):
        print "object created"

    @staticmethod
    def update_progress(self,value,ui_object): 
        ui_object.setText(QtGui.QApplication.translate("Dialog", "Progress: %s %%" % value, None))

        #MEMORY LEAK WHEN UPDATING TOO MUCH (H=0.0001 AND B=1000)
        QtGui.QApplication.processEvents() #update gui for pyqt



    @staticmethod
    def euler(b,h,progress):
        actions_done = 0
        actions_number = b * (1./h) #t = t+h. When h = 0.01 we need to perform t=t+h 100(1/h) times to get 1. 
                                    #when t varies from 0 to b, then we need to multiply this 1 * b(end time)
                                    #so we get b * (1/h) as a number of actions to perform

        scale = actions_number * 0.01

        while t <= b:
            actions_done+=1
            progress_value = (actions_done/actions_number)*100

            if (actions_done % scale == 0):
                Calculus.update_progress(None,progress_value, progress)         

            t += h

Answer 1

以您自己的方式调用thread.run()并不会像您认为的那样进行。当前，它只是在主线程中执行thread.run()方法。

调用thread.start()会启动线程，并自动调用thread.run()方法。这样，您需要在thread.run()方法的内的while循环。

这是因为您希望将完整的控制权传递给线程，并完成euler方法，以便可以将控制权返回到GUI事件循环(以便它可以处理重绘，以及更新进度条的方法)。 。您不应该尝试从主线程管理线程的执行。