如何獲得第一個和第二個對象

Question

我想知道如何獲得一個類的第一個和第二個對象。我實現了它的第一個對象：

PFQuery *query = [PFQuery queryWithClassName:@"YourClassName"]; 
[query orderByDescending:@"createdAt"]; 
[query getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) { 
    // code 
}]; 

從這裏，你有什麼建議來獲得下一個對象？

感謝

Answer 1

使用findObjects獲取匹配對象的數組。設置最大數量以返回.limit：

PFQuery *query = [PFQuery queryWithClassName:@"YourClassName"]; 
[query orderByDescending:@"createdAt"]; 
query.limit = 2; 
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) { 
    for (PFObject *object in objects) { 
     // this will run up to 2 times 
     NSLog("%@", object); 
    } 
}]; 

Answer 2

你只需要添加query.limit=2;。以下是整個代碼：

PFQuery *query = [PFQuery queryWithClassName:@"YourClassName"]; 
[query orderByDescending:@"createdAt"]; 
query.limit = 2; 
[query getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) { 
    // code 
}];