Question

我有两个班级User和Post。 User类有一个userType字段，我想从给定的userType中检索所有帖子，然后将其称为组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，但我不确定如何查询此数组或者这是否是正确的方法。怎么办呢？

Answer 1

Parse在查询时提供matchesQuery方法，所以......

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
}];

IOS Parse如何根据两个类从查询中检索对象？

1 个答案: