如何在Objective-C中进行深拷贝? [英] How can I make a deep copy in Objective-C?

问题描述

我正在学习ios开发，并且对Objective-C中的深层复制感到困惑. 例如，我下面有三个班.现在我想深入复制ClassA，有人可以教我完成复制方法吗?

I'm learning ios development and I'm confused with deep copying in Objective-C. For example,I have three class below. Now I want to deep copy ClassA, can anybody teach me to finish the copy method?

A:

@interface ClassA : NSObject <NSCopying>

@property (nonatomic, assign) int aInt;
@property (nonatomic, retain) ClassB *bClass;

@end

B:

@interface ClassB : NSObject <NSCopying>

@property (nonatomic, assign) int bInt;
@property (nonatomic, retain) ClassC *cClass;

@end

C:

@interface ClassC : NSObject <NSCopying>

@property (nonatomic, assign) int cInt;
@property (nonatomic, copy) NSString *str;

@end

推荐答案

您应该在要复制的每个类中添加copyWithZone:方法.

You should add the copyWithZone: method in each class you want to be copiable.

注意:我是手工写的，要注意打字错误.

NB: I wrote this by hand, watch out for typos.

-(id) copyWithZone:(NSZone *) zone
{
    ClassA *object = [super copyWithZone:zone];
    object.aInt = self.aInt;
    object.bClass = [self.bClass copyWithZone:zone];
    return object;
}

-(id) copyWithZone:(NSZone *) zone
{
    ClassB *object = [super copyWithZone:zone];
    object.bInt = self.bInt;
    object.cClass = [self.cClass copyWithZone:zone];
    return object;
}

-(id) copyWithZone:(NSZone *) zone
{
    ClassC *object = [super copyWithZone:zone];
    object.cInt = self.cInt;
    object.str = [self.str copy];
    return object;
}

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