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Question

在mja的帮助下，我成功地使用RestKit和Objective-C建立了简单的对象映射。请参阅我之前的问题here。

我的下一步是尝试以相同的方式处理嵌套的JSON。

我的JSON看起来像这样，外部是带有一些嵌套'投票'的CandidatePhrase：

{ "Id":33696,
"Phrase": "phrase",
"BadCount":0,
"Votes":[{"Id":447,"OriginalId":33696,"Votes":2,"Translation":"translation 1"},
{"Id":746,"OriginalId":33696,"Votes":1,"Translation":"translation 2"},
{"Id":747,"OriginalId":33696,"Votes":1,"Translation":"translation 3"}
]}

我在AppDelegate中创建了一个关系，如下所示：

[candidatePhraseMapping mapKeyPath:@"votes" toRelationship:@"vote" withMapping:voteMapping];

当我在控制器中调用make我的请求时，我能够处理其余的CandidatePhrase，但是我不确定如何将嵌套的'Vote'对象映射到数组中以便我可以在一个TableView

（像这样的伪代码......）

// Store the votes in an array
_votes = [[NSArray alloc] initWithObjects:myCandidatePhrase.votes, nil];

这是我的CandidatePhrase对象

@interface CandidatePhrase : NSObject

@property (nonatomic, retain) NSNumber* ident;
@property (nonatomic, retain) NSNumber* badcount;
@property (nonatomic, retain) NSString* phrase;
@property (nonatomic, retain) NSArray* votes;

@end

和我的投票对象

@interface Vote : NSObject

@property (nonatomic, retain) NSNumber* ident;
@property (nonatomic, retain) NSNumber* originalId;
@property (nonatomic, retain) NSNumber* votecount;
@property (nonatomic, retain) NSString* translation;

+ (id)voteWithTranslationId:(NSNumber *)ident translation:(NSString *)translation;

@end

非常感谢任何帮助。

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以下是我的映射代码

// Votes Mapping

RKObjectMapping* voteMapping = [RKObjectMapping mappingForClass:[Vote class]];
[voteMapping mapKeyPath:@"Id" toAttribute:@"ident"];
[voteMapping mapKeyPath:@"OriginalId" toAttribute:@"originalId"];
[voteMapping mapKeyPath:@"Votes" toAttribute:@"votecount"];
[voteMapping mapKeyPath:@"Translation" toAttribute:@"translation"];

[[manager mappingProvider] addObjectMapping:voteMapping];

// Candidate Phrase Mapping
RKObjectMapping *candidatePhraseMapping = [RKObjectMapping mappingForClass:[CandidatePhrase class]];

[candidatePhraseMapping mapKeyPath:@"Id" toAttribute:@"ident"];
[candidatePhraseMapping mapKeyPath:@"Phrase" toAttribute:@"phrase"];
[candidatePhraseMapping mapKeyPath:@"BadCount" toAttribute:@"badcount"];

[candidatePhraseMapping mapKeyPath:@"Votes" toRelationship:@"votes" withMapping:voteMapping];

[[manager mappingProvider] addObjectMapping:candidatePhraseMapping];

为清楚起见，这里是我试图访问控制器上的投票项目

- (void)objectLoader:(RKObjectLoader*)objectLoader didLoadObject:(id)object 
{ 
    CandidatePhrase *myCandidatePhrase = (CandidatePhrase*)object;
    self.candidateText.text = myCandidatePhrase.phrase; <-- works fine

    _votes = [[NSArray alloc] initWithObjects:myCandidatePhrase.votes, nil];
    for (id o2 in _votes) { 
        //Vote *vote = o2; 
        NSLog(@"Item name: %@", o2); <-- sees object but crashes
    }

    NSLog(@"Votes: %@", myCandidatePhrase.votes); 
    _votes = [[NSArray alloc] initWithObjects:myCandidatePhrase.votes, nil];
     [_votesTableView reloadData];
 }

我的表与

绑定

Vote *vote = [_votes objectAtIndex:indexPath.row];
cell.textLabel.text = vote.translation;

Answer 1

您无需手动管理嵌套的NSArray。我相信问题可能只是一个简单的错字，因为你映射keyPath“投票”，但你的json包含大写“V”的“投票”。

[candidatePhraseMapping mapKeyPath:@"Votes" toRelationship:@"votes" withMapping:voteMapping];

如果这样做无效，请随时发表评论并使用voteMapping更新您的问题。

此外，didLoadObject的内容可以简化：

//in .h file
@property (nonatomic, retain) NSArray* votes;

// in implementation
@synthesize votes;

...
- (void)objectLoader:(RKObjectLoader*)objectLoader didLoadObject:(id)object 
{ 
    CandidatePhrase *myCandidatePhrase = (CandidatePhrase*)object;
    self.candidateText.text = myCandidatePhrase.phrase;
    self.votes = myCandidatePhrase.votes;
}

使用Objective-C在Xcode中使用RestKit映射嵌套对象

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1 个答案: