React native context and deprecated super usage
来源： https://stackoverflow.com/questions/63883401/react-native-context-and-deprecated-super-usage
super
Java - parent class is calling a method from a child class?
来源： https://stackoverflow.com/questions/45047559/java-parent-class-is-calling-a-method-from-a-child-class
clarification/when/where to use super in django/python
来源： https://stackoverflow.com/questions/19197684/clarification-when-where-to-use-super-in-django-python
How does derived class arguments work in Python?
问题 I am having difficulty understanding one thing in Python.I have been coding in Python from a very long time but there's is something that just struck me today which i struggle to understand So the situation goes like this I have a mixin and a view class Mixin: def get_session(self,request,*args,**kwargs): print(self) #should be the instance passed print(request) #should be the request object passed but it's also an instance class View: def get(self,request,*args,**kwargs): self.get_session
How does derived class arguments work in Python?
问题 I am having difficulty understanding one thing in Python.I have been coding in Python from a very long time but there's is something that just struck me today which i struggle to understand So the situation goes like this I have a mixin and a view class Mixin: def get_session(self,request,*args,**kwargs): print(self) #should be the instance passed print(request) #should be the request object passed but it's also an instance class View: def get(self,request,*args,**kwargs): self.get_session
How does derived class arguments work in Python?
问题 I am having difficulty understanding one thing in Python.I have been coding in Python from a very long time but there's is something that just struck me today which i struggle to understand So the situation goes like this I have a mixin and a view class Mixin: def get_session(self,request,*args,**kwargs): print(self) #should be the instance passed print(request) #should be the request object passed but it's also an instance class View: def get(self,request,*args,**kwargs): self.get_session
Why do we not need to include self in super()?
问题 Why in super() keyword, can we omit self ? What if we don't omit it? class A: def __init__(self, var1, var2): """ some code """ class B(A): def __init__(self, varA, varB): super().__init__(varA, varB) """ some code """ 回答1: class Rectangle: def __init__(self, length, width): self.length = length self.width = width def area(self): return self.length * self.width def perimeter(self): return 2 * self.length + 2 * self.width class Square(Rectangle): def __init__(self, length): super(Square, self)
java中super 的两种用法
通过用 static 来定义方法或成员，为我们编程提供了某种便利，从某种程度上可以说它类似于 C 语言中的全局函数和全局变量。但是，并不是说有了这种便利，你便可以随处使用，如果那样的话，你便需要认真考虑一下自己是否在用面向对象的思想编程，自己的程序是否是面向对象的。 好了，现在开始讨论 this&super 这两个关键字的意义和用法。 在 Java 中， this 通常指当前对象， super 则指父类的。当你想要引用当前对象的某种东西，比如当前对象的某个方法，或当前对象的某个成员，你便可以利用 this 来实现这个目的，当然， this 的另一个用途是调用当前对象的另一个构造函数，这些马上就要讨论。如果你想引用父类的某种东西，则非 super 莫属。由于 this 与 super 有如此相似的一些特性和与生俱来的某种关系，所以我们在这一块儿来讨论，希望能帮助你区分和掌握它们两个。 在一般方法中 最普遍的情况就是，在你的方法中的某个形参名与当前对象的某个成员有相同的名字，这时为了不至于混淆，你便需要明确使用 this 关键字来指明你要使用某个成员，使用方法是 “this. 成员名 ” ，而不带 this 的那个便是形参。另外，还可以用 “this. 方法名 ” 来引用当前对象的某个方法，但这时 this 就不是必须的了，你可以直接用方法名来访问那个方法
super respondsToSelector: returns true but actually calling super (selector) gives “unrecognized selector sent to instance”
问题 OK, I am a little confused. I have a subclass of UIScrollView, which is my attempt at a horizontally scrolling "table view" like UI element. UIScrollView itself sets up UIGestureRecognizers it uses internally, and it appears to set itself up as the delegate for those UIGestureRecognizers. I also have my own UIGestureRecognizer setup on my horizontal table elements/cells and my own class set as delegate for my own UIGestureRecognizer. Since my class is a subclass of UIScrollView, at runtime,
super respondsToSelector: returns true but actually calling super (selector) gives “unrecognized selector sent to instance”
问题 OK, I am a little confused. I have a subclass of UIScrollView, which is my attempt at a horizontally scrolling "table view" like UI element. UIScrollView itself sets up UIGestureRecognizers it uses internally, and it appears to set itself up as the delegate for those UIGestureRecognizers. I also have my own UIGestureRecognizer setup on my horizontal table elements/cells and my own class set as delegate for my own UIGestureRecognizer. Since my class is a subclass of UIScrollView, at runtime,