ios - 将 NSArray 属性添加到子类 PFObject

Question

我有两个子类 PFObject，如下所示:

@interface BQQuestion : PFObject<PFSubclassing>

@property (retain) NSString *user;
@property (retain) NSString *questionText;
@property (retain) NSArray *answers; //this is intended to hold an array of BQAnswers 

+ (NSString *)parseClassName;

@end


@interface BQAnswer : PFObject<PFSubclassing>

@property (retain) NSString *user;
@property (retain) BQQuestion *question;
@property (retain) NSString *answerText;
@property int votes;

+(NSString *)parseClassName;

@end

我尝试使用以下代码将 BQAnswers 添加到 BQQuestion 的答案属性:

    BQQuestion *t = [BQQuestion object];
    t.questionText = @"Another test";
    BQAnswer *one = [BQAnswer object];
    one.answerText = @"Very nice.";
    BQAnswer *two = [BQAnswer object];
    two.answerText = @"Good.";

    t.answers = @[one, two];

    [t saveInBackground];

t、一和二都保存到 Parse 云中，但没有为 BQQuestion.answers 生成列，因此不会保存关联。我在这里弄错了什么？

任何帮助将不胜感激。谢谢!

Answer 1

指向 PFObject 数组的指针是 PFRelation。为此，您需要在 Question 对象中创建一个列，其中包含指向 Answer 对象的关系。我假设您的解析类称为“问题”，并且添加的包含指向答案的关系的列称为“答案”

BQQuestion *question = [PFObject objectWithClassName:@"Question"];
PFRelation *answers = [t relationForKey:@"answers"];
for (PFObject *answer in answers) {
  [question add:answer];
}
[question saveInBackground];

检索答案对象:

BQQuestion *question = //assume you have the question object;
PFRelation *answers = [question relationForKey:@"answers"];
PFQuery *query = [answers query];
[query findObjectsInBackgroundWithBlock:^(NSArray *results, NSError *error) {
    // results contains all the answers to that question
}];