我的对象CCategory.h
@interface CCategory : NSObject
@property(strong, nonatomic) NSNumber * _Nonnull categoryId;
@property(strong, nonatomic) NSNumber * _Nonnull originalId;
@property(strong, nonatomic) NSString * _Nonnull name;
@property(strong, nonatomic) NSString * _Nonnull type;
@property(nonatomic, strong) CCategory * _Nullable parent;
@property (nullable, nonatomic, retain) NSOrderedSet<CCategory *> *children;
- (instancetype _Nonnull )initWithId:(NSNumber *_Nullable)categoryId
andOriginalId:(NSNumber *_Nullable)originalId
andName:(NSString *_Nonnull)name
andType:(NSString *_Nonnull)type
andParent:(CCategory *_Nullable)parent
andChildren:(NSOrderedSet<CCategory *> *_Nullable)children NS_DESIGNATED_INITIALIZER;
@end
CCategory.m
@implementation CCategory
- (instancetype)init {
return [self initWithId:0 andOriginalId:0 andName:@"" andType:@"" andParent:nil andChildren:nil];
}
- (instancetype)initWithId:(NSNumber *)categoryId
andOriginalId:(NSNumber *)originalId
andName:(NSString *)name
andType:(NSString *)type
andParent:(CCategory *)parent
andChildren:(NSOrderedSet<CCategory *> *)children {
self = [super init];
if (self) {
self.categoryId = categoryId;
self.originalId = originalId;
self.name = name;
self.type = type;
self.parent = parent;
self.children = children;
}
return self;
}
@end
这是我检查类类型的方式:
CCategory * firstItem = [itemsArray objectAtIndex:0];
CCategory *child = [firstItem.children objectAtIndex:0];
NSString *className = NSStringFromClass([child class]);
NSLog(@"First Item is: %@", className);
firstItem 返回类型CCategory
,child 返回类型NSDictionary
从数据库接收对象包含所有数据后,但children由于某种原因是NSDictionary
类型,而不是CCategory
类类型。这是为什么?以及如何让 child 输入 CCategory
?
最佳答案
因为您声明了某个类的某个对象并不意味着它属于正确的类。 例如,如果你写
NSArray *array = [@[@"Hello"] firstObject];
array
实际上是一个 NSString
对象。
因此,当您解析您的响应并创建您的 CCategory
时我猜的对象 NSDictionary
对象。
这就是为什么 children
似乎实际上是一个 NSOrderedSet
的 NSDictionary
而不是 CCategory
对象。
一种可能的方法是递归调用 initWithId:andOriginalId:andName:andType:andParent:andChildren:
为了 children 。
所以不是 self.children = children;
NSMutableOrderedSet *childrenSet = [[NSMutableOrderedSet alloc] init];
for (NSDictionary *aChildDict in [children array])
{
CCategory *aChild = [CCategory alloc] initWithId:aChildDict[keyWhereThereIsID], etc.]
[childrenSet addObject:aChild];
}
self.children = childrenSet;
但是像在 init
中那样设置它更像是一种技巧。方法,因为它说 children
应该是 NSOrderedSet<CCategory *> *
.
所以由您决定,要么重命名该方法以明确其作用,要么接受 NSOrderedSet<NSDictionary *> *
对于 children
相反,先解析它,再创建一个,等等。
一个可能的懒惰选择是这样做:
重命名为 andChildren:(NSOrderedSet *)children
NSMutableOrderedSet *childrenSet = [[NSMutableOrderedSet alloc] init];
for (id *aChildObject in [children array])
{
CCategory *aChild = nil;
if ([aChildObject isKindOfClass:[NSDictionary class]]) //Need parsing
{
NSDictionary *aChildDict = (NSDictionary *)aChildObject;
aChild = [CCategory alloc] initWithId:aChildDict[keyWhereThereIsID], etc.];
}
else if ([aChildObject isKindOfClass:[CCategory class]]) //Already a CCategory Object
{
aChild = (CCategory *)aChildObject;
}
else
{
NSLog(@"Ooops, child of wrong class: %@", NSStringFromClass([aChildObject class]);
}
if (aChild) { [childrenSet addObject:aChild]; }
}
self.children = childrenSet;
关于ios - 自定义对象返回 NSDictionary 作为类型,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/44543412/