Python：RuntimeError：从未调用％S的超类__init __（） [英] Python: RuntimeError: super-class __init__() of %S was never called
问题描述
我试图对Python中的对象（继承自不同类的类的实例，具体来说，<$ c）进行某些操作（ setParent ） $ c> QtGui.QLabel ），但在运行时出现了上述错误。对象本身具有一些具有实际内容的字段（已在调试中验证），但是由于某种原因，我无法使用它。错误是什么意思，我该如何解决？有关其他信息，我将说该对象是在尝试对该对象进行操作之前从静态方法返回的。
I tried to do some operation (setParent) on an object in Python (an instance of a class which inherits from a different class - to be specific, QtGui.QLabel), but during runtime the above error was raised. The object itself has had some fields with actual content (verified on debug), but from some reason I couldn't "use" it. What does the error mean and how can I fix it? For some additional information, I shall say that the object was returned from a static method before I tried to do this operation on it.
子类的 __ init __（）本身的功能：
def __init__(self, image, father):
super(AtomicFactory.Image, self).__init__(father)
self.raw_attributes = image.attributes
self.attributes = {}
father.addChild(self)
self.update()
现在我写了一个类似的代码，一个简单的，窗口移动时，在 widget.setParent（mw）行上出现相同的错误。
Now I wrote a similar code, a simple one, that had the same error on the line widget.setParent(mw) when the window was moved.
#!/usr/bin/env python
import sys
import copy
from PyQt4 import QtCore, QtGui
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
main_widget=QtGui.QWidget()
widget = QtGui.QPushButton('Test')
widget.resize(640, 480)
widget.setParent(main_widget)
widget.move(0, 0)
widget2=QtGui.QPushButton('Test2')
widget2.i=0
widget2.resize(600, 200)
widget2.setParent(main_widget)
widget2.move(640, 0)
def onResize(event):
print event
mw=copy.deepcopy(main_widget)
widget.setParent(mw)
widget2.setParent(mw)
widget.move(0, 0)
widget2.move(640, 480)
main_widget_width=main_widget.width()
widget_width=widget.width()
width2=main_widget_width-widget_width
height2=widget2.height()
widget2.resize(width2, height2)
widget2.move(640, 0)
main_widget.resizeEvent=onResize
def onClick():
size=(widget2.width(), widget2.height())
if(widget2.i%2==0):
widget2.resize(int(size[0]/2), int(size[1]/2))
else:
widget2.resize(size[0]*2, size[1]*2)
widget2.i+=1
QtCore.QObject.connect(widget, QtCore.SIGNAL('clicked()'), onClick)
main_widget.show()
sys.exit(app.exec_())
出了什么问题？
推荐答案
如果要继承 QObject （或 QWidget ），则必须始终调用超类 __ init __ ：
If you want to inherit QObject (or QWidget), you must always call the super-class __init__:
class MyObject(QObject):
def __init__(self, *args, **kwargs):
super(MyObject, self).__init__(arguments to parent class)
#other stuff here
您也可以在之后叫家长的班级的 __ init __ 一些说明，但是除非您这样做，否则您不能调用 QObject 方法或使用 QObject 属性。
You may also call the parent's class's __init__ after some instructions, but you can't call QObject methods or use QObject attributes until you did so.
编辑：
在您的情况下，您尝试 QWidget ，但这不可能。
Python也许可以复制 QWidget 的包装器，但是 QWidget 本身是python无法使用默认实现 copy.deepcopy 处理的C ++对象，因此，每当调用复制实例的方法时，都会得到 RuntimeError ，因为底层C ++对象未正确初始化。
Edit:
In your case you are trying to deepcopy a QWidget, but this is not possible.
Python may be able to copy the wrapper of the QWidget, but the QWidget itself is a C++ object that python cannot handle with the default implementation of copy.deepcopy, hence whenever you call a method of the copied instance you get the RuntimeError because the underlying C++ object wasn't initialized properly.
对这些对象进行腌制也是如此。 Python能够腌制包装器，而不是C ++对象本身，因此取消腌制实例时，结果是损坏的实例。
The same is true for pickling these objects. Python is able to pickle the wrapper, not the C++ object itself, hence when unpickling the instance the result is a corrupted instance.
为了支持 deepcopy（） QWidget 类应实现 __ deepcopy __ 方法，但不是做到这一点。
In order to support deepcopy() the QWidget class should implement the __deepcopy__ method, but it does not do that.
如果要复制小部件，则必须自己通过以下方式实现所有机制：手。
If you want to copy widgets you'll have to implement by yourself all the mechanism by hand.
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