当我试图覆盖一个getter时，这个语法是什么？ [英] What is this syntax when I was attempting to override a getter?

问题描述

当我试图覆盖一个getter时，这个语法是什么？

What is this syntax when I was attempting to override a getter??

我只是想弄清楚如何在Objective-C中了解属性的工作原理。这是我的财产：

I'm just messing around trying to learn more about how properties work in Objective-C. Here is my property:

@property (nonatomic, strong) UIView *myView;

当我尝试覆盖getter时，我得到了这个帮助：

When I try to override the getter I get this help:

-(void)getMyView:(<object-type> **)buffer range:(NSRange)inRange
{

}

我知道我可以使用这个：

I know I can use this:

-(UIView *)myView
{

}

但我很好奇以前的方法做了什么，为什么它在那里，等等。感谢您的帮助！

But I am just curious as to what the previous method does, why it's there, etc. Thanks for any help!

推荐答案

它被称为Getter索引访问器，如键值编码编程指南

It's called "Getter Indexed Accessors" as explained in the Key-Value Coding Programming Guide

来自文档：

为了支持对有序多对多关系的只读访问，请实现以下方法：

In order to support read-only access to an ordered to-many relationship, implement the following methods:

-countOf<钥匙及GT; 必需。这类似于NSArray原始方法计数。

-countOf<Key> Required. This is the analogous to the NSArray primitive method count.

-objectIn< Key> AtIndex：或 - < key> AtIndexes：必须实现其中一种方法。它们对应于NSArray方法 objectAtIndex：和 objectsAtIndexes：

-objectIn<Key>AtIndex: or -<key>AtIndexes: One of these methods must be implemented. They correspond to the NSArray methods objectAtIndex: and objectsAtIndexes:

-get< Key>：range：实现此方法是可选的，但可以提供额外的性能提升。此方法对应于 NSArray 方法 getObjects：range：。

-get<Key>:range: Implementing this method is optional, but offers additional performance gains. This method corresponds to the NSArray method getObjects:range:.

您可以出于性能原因实施此类方法，如指南中所述

You can implement such methods for performance reasons, as explained in the guide

如果基准测试表明要求性能改进，您还可以实现 -get< Key>：range：。这个访问器的实现应该在缓冲区中返回，作为第一个参数给出的对象落在第二个参数指定的范围内。

If benchmarking indicates that performance improvements are required, you can also implement -get<Key>:range:. Your implementation of this accessor should return in the buffer given as the first parameter the objects that fall within the range specified by the second parameter.

例如

- (void)getEmployees:(Employee * __unsafe_unretained *)buffer range:(NSRange)inRange {
    // Return the objects in the specified range in the provided buffer.
    // For example, if the employees were stored in an underlying NSArray
    [self.employees getObjects:buffer range:inRange];
}

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