在Cocoa / Objective-C中有一个类似的列表吗？ [英] Is there anything like a generic list in Cocoa / Objective-C?

问题描述

我在C＃中真正喜欢的是通用列表。可以只包含一种类型的对象的列表。
在Cocoa / Objective-C中有一个类似的列表吗？到目前为止我只知道 NSArray 谁将指向任何对象的指针。

What I really like in C# are generic lists. A list that can contain only one type of objects. Is there something like a generic list in Cocoa/Objective-C? As far I only know NSArray who will take a pointer to any object.

推荐答案

想在Cocoa应用程式中使用这个程式通常是设计薄弱的标志。

Wanting this in a Cocoa app is often a sign of a weak design.

NSArray 是不可变的，所以它不会指向任何对象，并且可能已经包含正确的对象，当交给你。我认为你更担心的是一个 NSMutableArray ，你认为你的代码的其他部分可能会添加错误的对象排序。但是看看Cocoa本身;

NSArray is immutable, so it will not "take a pointer to any object" and presumably already contains the correct objects when handed to you. What I assume you're more worried about is an NSMutableArray where you think other parts of your code might add the wrong sort of object. But have a look at Cocoa itself; it's incredibly rare to expose a mutable array as part of a class's design.

相反，你通常会暴露一个 NSArray 以及用于修改该阵列的几种方法。

Instead, you generally expose an NSArray and a couple of methods for modifying that array. Something along the lines of:

@class Foo : NSObject
- (NSArray *)bars;
- (void)addBar:(Bar *)bar;
- (void)removeBar:(Bar *)bar;
@end

这通常通过编译器警告来停止错误的对象，那么当然你可以在 -addBar：和 -removeBar：中添加断言。

This generally stops wrong objects being inserted simply by having a compiler warning, and then of course you can add assertions within -addBar: and -removeBar: if you wish too.

这篇关于在Cocoa / Objective-C中有一个类似的列表吗？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！