class | 易学教程

Vue指令

阅读更多关于 Vue指令

文本指令　 {{ msg }}  原文本   {{ msg }} 斗篷指令 [v-cloak] { display: none; } //放在style中属性指令　　  　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　<div

replacing self->isa because of Xcode 4.6 deprecation

阅读更多关于 replacing self->isa because of Xcode 4.6 deprecation

问题 I just installed Xcode 4.6 and now I'm getting new errors in an ancient code I manage. the compiler now complains about "Direct access to objective-c's isa is deprecated in favor of object_setClass() and object_getClass()" and won't build. so my question is, is this the correct equivalent ? self->isa = [CustomClass class]; replaced with: object_setClass(self, [CustomClass class]); thank you 回答1: Accessing isa has been deprecated for some time, the tools just didn't tell you this. Notably, it

Trigger an event when a function is called in a class

阅读更多关于 Trigger an event when a function is called in a class

问题 Is is possible in PHP to trigger an event whenever a function in a class is called, without adding it to every function in the class? Example: <?php class A { function xxx() { //this function will be called everytime I call another function in this class } public static function b() { return 'Hello Stackoverflow!'; } public static function c() { //I also want this function to trigger the event! } } echo A::b(); ?> 回答1: AFAIK there are no native language constructs for this. If you need it for

Can static methods in javascript call non static

阅读更多关于 Can static methods in javascript call non static

问题 I am curious as I get a "undefined is not a function" error. Consider the following class: var FlareError = require('../flare_error.js'); class Currency { constructor() { this._currencyStore = []; } static store(currency) { for (var key in currency) { if (currency.hasOwnProperty(key) && currency[key] !== "") { if (Object.keys(JSON.parse(currency[key])).length > 0) { var currencyObject = JSON.parse(currency[key]); this.currencyValidator(currencyObject); currencyObject["current_amount"] = 0;

Dynamically instantiate a typed Vector from function argument?

阅读更多关于 Dynamically instantiate a typed Vector from function argument?

问题 For a game I'm attempting to develop, I am writing a resource pool class in order to recycle objects without calling the "new" operator. I would like to be able to specify the size of the pool, and I would like it to be strongly typed. Because of these considerations, I think that a Vector would be my best choice. However, as Vector is a final class, I can't extend it. So, I figured I'd use composition instead of inheritance, in this case. The problem I'm seeing is this - I want to

Creating an abstract class that implements multiple interfaces in c#

阅读更多关于 Creating an abstract class that implements multiple interfaces in c#

问题 I'd like to create an abstract class in c#, that "inherits" from different interfaces, but leaves the concrete implementation to the subclass. The compiler however complains, that the class doesnt implement the methods specified in the interfaces. I'm used to Java where this always worked, so I'm not sure how it is supposed to work in c#. Anyway, this is my code: public abstract class MyClass : IDisposable, IPartImportsSatisfiedNotification { private string name; public MyClass(string name) {

C++ - How do I initialize a constructor of a separate class from the constructor of a class?

阅读更多关于 C++ - How do I initialize a constructor of a separate class from the constructor of a class?

问题 Basically what I am trying to achieve is to create a local (and private) instance of the class deltaKinematics in the class geneticAlgorithm In the geneticAlgorithm.h file I have: class DeltaKinematics; //class is defined in separate linked files class GeneticAlgorithm { //private DeltaKinematics deltaRobot; public: GeneticAlgorithm(); //constructor }; This is all fine, but when I go to declare the GeneticAlgorithm constructor, I can't work out how to construct the instance of DeltaKinematics

Is there standard Option or Nullable class in Java?

阅读更多关于 Is there standard Option or Nullable class in Java?

问题 Nullable (C#) has a bit different meaning, but anyway both Option (Scala) and Nullable can be used to express the notion of "value or nothing". For example in case when you would like to find substring in a string -- instead of obscure -1 as Int, it would be better to return Option[Int] (in Scala it would be None for nothing). Is there such class in standard Java? If yes, what it is? Please note, I am not asking how to write such class. Update As I wrote, Nullable has different meaning.

Python : How to “merge” two class

阅读更多关于 Python : How to “merge” two class

问题 I want to add some attributes and methodes into various class. The methodes and attributes that I have to add are the same but not the class to assign them, so I want to construct a class who assign new methodes and attribute for a class given in argument. I try this but it's not working: (I know that is a very wrong way to try to assign something to self, it's just to show what I want to do) class A: def __init__(self): self.a = 'a' def getatt(self): return self.a class B: def __init__(self,

Sharing global variables between classes in Python

阅读更多关于 Sharing global variables between classes in Python

问题 I'm relatively new to thinking of python in terms of object-oriented programming, and it's coming relatively slowly to me. Is it possible to pass global variables between classes with multiple functions in them? I've read extensively about them here and in other sources, but I'm still a bit confused. My ultimate goal is to define a variable globally, assign it a value in a function of one class, and then USE it in another class's function. Is that possible? I'm building a pythonaddin for