ios - iOS解析如何从基于两个类的查询中检索对象？

Question

我有两个类User和Post。 User类具有userType字段，我想从给定的userType检索所有帖子，我们将其称为组x。在Post类中，我有一个指向User类的指针。

我试图做类似的事情，首先检索我想要的用户类型的所有用户ID:

PFQuery *queryUser = [PFQuery queryWithClassName:kFTUserClassKey];
[queryUser whereKey:kFTUserTypeKey equalTo:kFTUserTypeX];
[queryUser whereKey:kFTUserLocationKey nearGeoPoint:nearGeoPoint withinMiles:miles];
[queryUser findObjectsInBackgroundWithBlock:^(NSArray *usersTypeX, NSError *error) {
            if (!error) {
                NSMutableArray *objectIds = [[NSMutableArray alloc] init];

                // Add ambassador ids into query
                for (PFObject *userX in usersTypeX) {
                    [objectIds addObject:[PFObject objectWithoutDataWithClassName:kFTUserClassName objectId: userX.objectId]];
                }
            }
}];

然后我想基于这些objectIds进行查询，但是我不确定如何在此数组上进行查询，或者这是否是执行此操作的正确方法。如何才能做到这一点？

Answer 1

解析为查询提供了matchesQuery方法，因此...

PFQuery *innerQuery = [PFQuery queryWithClassName:@"User"];
[innerQuery whereKey:@"userType" equalTo:@"X"];  // fix with your real user type
PFQuery *query = [PFQuery queryWithClassName:@"Post"];
[query whereKey:@"user" matchesQuery:innerQuery];
[query findObjectsInBackgroundWithBlock:^(NSArray *posts, NSError *error) {
    // posts are posts where post.user.userType == X
}];