如何使用Objective-C从Parse for iOS中的二级指针检索值

Question

我在Parse中有以下结构

Class_A

1. 的objectID
2. b_ID（这是一个指针，其值为对象ID到B）

Class_B

1. 的objectID
2. c_ID（这是一个指针，其值为objectID到C）
3. someParameterinB

Class_C

1. 的objectID
2. someParameterinC

我正在使用以下代码进行检索;

PFQuery *query = [PFQuery queryWithClassName:@"Class_A"];
    [query includeKey:@"b_ID"];
    [query includeKey:@"Class_B.c_ID"];

    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
            // The find succeeded. The first 50 objects are available in object
            self.myArray = [[NSArray alloc] initWithArray:objects];
        } else {
            // Log details of the failure
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        }
    }];

现在，当谈到在UITableViewCell中显示时，我使用以下代码：

PFObject *aObject = [self.myArray objectAtIndex:indexPath.row];

PFObject *bObject = [aObject objectForKey:@"b_ID"];

PFObject *cObject = [bObject objectForKey:@"c_ID"];

我遇到了cObject的问题。你能帮忙吗？

Answer 1

替换这些行：

[query includeKey:@"b_ID"];
[query includeKey:@"Class_B.c_ID"];

与

[query includeKey:@"b_ID.c_ID"];

，查询响应将同时包含B和C个对象。