python - 在python中，子进程调用父进程的方法而不调用父进程的__init__

Question

我有一个程序，在主线程的 PyQt 中有一个 gui。它与光电探测器通信并在另一个线程中获取功率读数，该线程向主线程发送信号以更新 GUI 的功率值。现在我想使用电机自动对齐光纤，从光电探测器获取反馈。

因此，我创建了一个控制电机的类，但我必须以某种方式将光电探测器读数传递给该类。首先，我尝试访问父级的 power 变量，但没有成功。然后我在 GUI 中创建了一个方法来返回变量的值，并尝试从电机类访问它。我遇到一个问题，说如果不先使用它的 __init__ ，我就无法使用父方法。有办法绕过它吗？我无法再次调用 gui __init__，我只想在子类中使用它的方法之一。

如果有其他方法可以做到这一点，我也会很高兴。

PS:我想我不能给子类光电探测器对象，因为它在另一个线程中，对吗？

--编辑--图形用户界面代码是:

class MyApp(QtGui.QMainWindow, Ui_MainWindow):
    self.PDvalue = 0 #initial PD value
    self.PDState = 0 #control the PD state (on-off)
    self.PDport =  self.dialog.pm100d.itemText(self.dialog.pm100d.currentIndex()) #gets pot info

    def __init__(self):
    ... #a lot of other stuff
    self.nano = AlgoNanoMax.NanoMax('COM12') #creates the motor object
    self.nano_maxX.clicked.connect(self.NanoMaximizeX) #connect its fun to a buttom
    self.actionConnect_PM100D.triggered.connect(self.ActionConnect_PM100D) #PD buttom

    def NanoMaximizeX(self): 
        self.nano.maximize_nano_x() #uses motor object function

    def ActionConnect_PM100D(self):
        if self.PDState == 0: #check if PD is on
            self.PD = PDThread(self.PDState, self.PDport) #creates thread
            self.PD.valueupdate.connect(self.PDHandler) #signal connect
            self.PD.dialogSignal.connect(self.PDdialog) #create error dialog
            self.threads = []
            self.threads.append(self.PD)
            self.PD.start() #start thread
        else:
            self.PDState = 0
            self.PD.state = 0 #stop thread
            self.startpd.setText('Start PD') #change buttom name


   def PDHandler(self, value):
       self.PDvalue = value #slot to get pow from thread

   def ReturnPow(self):
       return self.PDvalue #return pow (I tried to use this to pass to the motor class)

   def PDdialog(self):
       self.dialog.set_instrument('PM100D') #I have a dialog that says error and asks you to type the right port
       if self.dialog.exec_() ==  QtGui.QDialog.Accepted: #if Ok buttom try again
           ret = self.dialog.pm100d.itemText(self.dialog.pm100d.currentIndex()) #new port
           self.PD.port = str(ret) 
           self.PD.flagWhile = False #change PD stop loop condition to try again
       else: #pressed cancel, so it gives up
           self.PD.photodetector.__del__() #delete objects
           self.PD.terminate() #stop thread
           self.PD.quit()

现在是 PD 类，它位于另一个线程中，但与 gui 在同一个文件中:

class PDThread(QtCore.QThread):

valueupdate = QtCore.pyqtSignal(float) #creating signals
dialogSignal = QtCore.pyqtSignal() #signal in case of error
state = 1 #used to stop thread

def __init__(self, state, port):
    QtCore.QThread.__init__(self)
    self.photodetector = PM100D() #creates the PD object
    self.port = port

def run(self):
    while True:
        self.flagWhile = True #used to leave while
        try:
            self.photodetector.connect(self.port) #try to connect
        except:
            self.dialogSignal.emit() #emit error signal
            while self.flagWhile == True:
                time.sleep(0.5) #wait here until user press something in the dialog, which is in another thread
        else:
            break #leave loop when connected

    window.PDState = 1 #change state of main gui buttom (change functionality to turn off if pressed again)
    window.startpd.setText('Stop PD')   #change buttom label
    while self.state == 1:
        time.sleep(0.016)
        value = self.photodetector.get_pow() #get PD pow
        self.valueupdate.emit(value) #emit it

AlgoNanoMax 文件:

import gui
from NanoMax import Nano

class NanoMax(gui.MyApp): #inheriting parent

def __init__(self, mcontroller_port):
    self.mcontroller = Nano(mcontroller_port) #mcontroller is the communication to the motor

def maximize_nano_x(self, step=0.001, spiral_number=3):
    ''' Alignment procedure with the nano motor X'''
    print 'Optimizing X'
    power = super(NanoMax, self).ReturnPow() #here I try to read from the photodetector
    xpos = self.mcontroller.initial_position_x
    position = []
    position = [[power, xpos]]
    xsign = 1
    self.mcontroller.move_relative(self.mcontroller.xaxis, (-1) * spiral_number * step)
    print 'X nano move: '+ str((-1) * spiral_number * step * 1000) + ' micrometers'
    time.sleep(4)
    power = super(NanoMax, self).ReturnPow()
    xpos += (-1) * spiral_number * step
    position.append([power, xpos])
    for _ in xrange(2*spiral_number):
        self.mcontroller.move_relative(self.mcontroller.xaxis, xsign * step)
        print 'X nano move: '+ str(xsign * step * 1000) + ' micrometers'
        time.sleep(5)
        power = super(NanoMax, self).ReturnPow()
        xpos += xsign * step
        position.append([power, xpos])
    pospower = [position[i][0] for i in xrange(len(position))]
    optimalpoint = pospower.index(max(pospower))
    x_shift = (-1) * (xpos - position[optimalpoint][1])
    print 'Maximum power: ' + str(max(pospower)) + ' dBm'
    print 'Current power: ' + str(super(NanoMax, self).ReturnPow()) + ' dBm'
    self.mcontroller.move_relative(self.mcontroller.xaxis, x_shift)

Answer 1

__init__对于 NanoMax和MyApp应该打电话super().__init__()确保所有级别都完成初始化(如果这是Python 2，则不能使用 no-arg super ，因此它将分别是 super(NanoMax, self).__init__() 和 super(MyApp, self).__init__() )。这假设 PyQT已正确使用新式类编写，并正确使用 super本身;您正在使用super在其他地方，所以大概至少前者是正确的。使用super在所有类(class)中适本地进行将确保所有级别都是 __init__ -ed 一次，同时手动列出父类(super class)在某些继承模式下不起作用，或者可能调用一些 __init__多次或根本不。

如果许多级别可能需要参数，您还应该接受 *args/**kwargs并将其转发至super().__init__调用以便将参数转发到需要的地方。

将两者结合起来，您的代码应如下所示:

class MyApp(QtGui.QMainWindow, Ui_MainWindow):
    def __init__(self, *args, **kwargs):
        super(MyApp, self).__init__(*args, **kwargs)
        ... rest of __init__ ...

class PDThread(QtCore.QThread):
    def __init__(self, state, port, *args, **kwargs):
        super(PDThread, self).__init__(*args, **kwargs)
        ...

class NanoMax(gui.MyApp): #inheriting parent

    def __init__(self, mcontroller_port, *args, **kwargs):
        super(NanoMax, self).__init__(*args, **kwargs)
        self.mcontroller = Nano(mcontroller_port) #mcontroller is the communication to the motor

注意:如果您重载了父类(super class)可能在其 __init__ 中调用的方法，你的重载取决于你自己设置的状态 __init__ ，您需要在 super().__init__(...) 之前而不是之后设置该状态。称呼。合作多重继承可能会很痛苦。另请注意，对除最低级别类之外的任何内容使用位置参数在多重继承中可能会很丑陋，因此按关键字传递所有参数可能是有意义的，并且仅接受和转发 **kwargs ，不是*args ，因此人们不会以在继承层次结构稍有变化时就会中断的方式传递位置参数。