Ios 如何在Objective-C中复制自定义对象？

我有两个数组。第一个包含自定义对象。现在我想将第一个数组的所有对象复制到另一个数组中。为此，我使用下面的代码

Arays.

arr_post=[[NSMutableArray alloc]init];
copy_arr_user_post=[[NSMutableArray alloc]init];

我像这样将对象添加到它们中

for(i=0;i<[arr_main count];i++)
{
    Post *obj=[[Post alloc]init];
    obj.name=@"abc";
    obj.category=@"social";
   [arr_post addObject:obj];


}

在Post.h中

@interface Post : NSObject<NSCopying>

但它不复制对象，我得到空值。为什么？

试试看

NSMutableArray *  arr_post=[[NSMutableArray alloc]init];
NSMutableArray * copy_arr_user_post=[[NSMutableArray alloc]init];
for(int i=0;i<3;i++)
{
    Post *obj=[[Post alloc]init];
    obj.name=@"abc";
    obj.category=@"social";
    [arr_post addObject:obj];
}

[arr_post enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
    [copy_arr_user_post addObject:[obj copy]];
}];
Post * temp = [arr_post objectAtIndex:0];
temp.name = @"123";
NSLog(@"%@",arr_post);
NSLog(@"%@",copy_arr_user_post);

我为调试添加了

说明

-(NSString *)description{
    return [NSString stringWithFormat:@"%@ %@",self.name,self.category];
}

---

我发现一种比NSCopyng更快的方法

-使用这两种方法创建NSObject类别

#import <objc/runtime.h>
-(id)deepCopy
{
NSArray *tmpArray = @[self];
NSData *buffer = [NSKeyedArchiver archivedDataWithRootObject:tmpArray];
return [NSKeyedUnarchiver unarchiveObjectWithData:buffer][0];
}

- (NSMutableArray *)allProperties
{
    NSMutableArray *props = [NSMutableArray array];
    unsigned int outCount, i;
    objc_property_t *properties = class_copyPropertyList([self class], &outCount);
    for (i = 0; i < outCount; i++) {
        objc_property_t property = properties[i];

        //Excluding all readOnly properties
        unsigned int numOfAttributes;
        objc_property_attribute_t *propertyAttributes = property_copyAttributeList(property, &numOfAttributes);

        BOOL foundReadonly = NO;

        for ( unsigned int ai = 0; ai < numOfAttributes; ai++ )
        {
            switch (propertyAttributes[ai].name[0]) {
                case 'T': // type
                    break;
                case 'R': // readonly
                    foundReadonly = YES;
                    break;
                case 'C': // copy
                    break;
                case '&': // retain
                    break;
                case 'N': // nonatomic
                    break;
                case 'G': // custom getter
                    break;
                case 'S': // custom setter
                    break;
                case 'D': // dynamic
                    break;
                default:
                    break;
            }
        }
        free(propertyAttributes);

        if (!foundReadonly)
        {
            NSString *propertyName = [[NSString alloc] initWithCString:property_getName(property) encoding:NSASCIIStringEncoding];
            [props addObject:propertyName];
        }
    }
    free(properties);
    return props;
}

-导入类别

现在您可以复制任何类型的对象

MYObject *copy = [originalObject deepCopy];
NSArray *arrayWithCopiedObjects = [originalArray deepCopy];

---

等等……

澄清您的问题，在发布的代码中，您在哪里获得了

nil

值？哪些代码没有按预期工作？我认为这是研究深度复制集合的一个非常有用的链接：当我从第二个数组中获取对象时，我得到的值为零。你不能在数组中存储

nil

对象，因此数组本身必须是

nil

“现在你可以复制任何类型的对象了”-否。现在您可以复制任何对象及其属性。这仅适用于只需要复制特性的简单对象。我有很多类不适合这样做。这也不会递归地进行深度复制。

-(NSString *)description{
    return [NSString stringWithFormat:@"%@ %@",self.name,self.category];
}

#import <objc/runtime.h>
-(id)deepCopy
{
NSArray *tmpArray = @[self];
NSData *buffer = [NSKeyedArchiver archivedDataWithRootObject:tmpArray];
return [NSKeyedUnarchiver unarchiveObjectWithData:buffer][0];
}

- (NSMutableArray *)allProperties
{
    NSMutableArray *props = [NSMutableArray array];
    unsigned int outCount, i;
    objc_property_t *properties = class_copyPropertyList([self class], &outCount);
    for (i = 0; i < outCount; i++) {
        objc_property_t property = properties[i];

        //Excluding all readOnly properties
        unsigned int numOfAttributes;
        objc_property_attribute_t *propertyAttributes = property_copyAttributeList(property, &numOfAttributes);

        BOOL foundReadonly = NO;

        for ( unsigned int ai = 0; ai < numOfAttributes; ai++ )
        {
            switch (propertyAttributes[ai].name[0]) {
                case 'T': // type
                    break;
                case 'R': // readonly
                    foundReadonly = YES;
                    break;
                case 'C': // copy
                    break;
                case '&': // retain
                    break;
                case 'N': // nonatomic
                    break;
                case 'G': // custom getter
                    break;
                case 'S': // custom setter
                    break;
                case 'D': // dynamic
                    break;
                default:
                    break;
            }
        }
        free(propertyAttributes);

        if (!foundReadonly)
        {
            NSString *propertyName = [[NSString alloc] initWithCString:property_getName(property) encoding:NSASCIIStringEncoding];
            [props addObject:propertyName];
        }
    }
    free(properties);
    return props;
}

#pragma mark - NSCoding
- (instancetype)initWithCoder:(NSCoder *)decoder {
    self = [super init];
    if (self)
    {
        NSArray *keys = [self allProperties];

        for (NSString *key in keys)
        {
            [self setValue:[decoder decodeObjectForKey:key] forKey:key] ;
        }

    }
    return self;
}
- (void)encodeWithCoder:(NSCoder *)aCoder
{
    NSArray *keys = [self allProperties];

    for (NSString *key in keys)
    {
        [aCoder encodeObject:[self valueForKey:key] forKey:key];
    }
}

MYObject *copy = [originalObject deepCopy];
NSArray *arrayWithCopiedObjects = [originalArray deepCopy];