ios快速解析：如何收集指针数据

Question

我有这个查询：

        var query = PFQuery(className: "CardSet")
        query.whereKey("user", equalTo: PFUser.currentUser())
        query.findObjectsInBackgroundWithBlock { (objects, error) -> Void in

            if (error == nil) {

                // found

            }else{
                println(error.userInfo)
            }
        }

结果看起来像这样：

<CardSet: 0x7c892120, objectId: 2yty7cpnyF, localId: (null)> {
    ACL = "<PFACL: 0x7be65450>";
    lesson = "<Lesson: 0x7beaabd0, objectId: JV7trFTx5Z>";
    name = "I am your CardSet";
    public = 1;
    user = "<PFUser: 0x7be834a0, objectId: baz8ObNsmM>";
}

类“ CardSet”具有指向类“课程”的指针“课程”。 如何在查询结果中提供Lesson.name？ 还是我需要第二次查询？ 由于要解析的请求量很大，这会很糟糕...？ 有什么更好的方法可以在一个查询中获取所有指向的数据？

Answer 1

您可以使用includeKey方法告诉Parse获取相关对象：

var query = PFQuery(className: "CardSet")
query.whereKey("user", equalTo: PFUser.currentUser())
query.includeKey("lesson")
query.findObjectsInBackgroundWithBlock { (objects: [AnyObject]!, error: NSError!) in
    for cardset in objects {
        var lesson = cardset["lesson"] as PFObject
        var name = lesson["name"] as String
        println("retrieved related lesson: \(post) with name: \(name)")
    }
}

在文档的“ 关系查询”部分中提到。

Answer 2

您传递了一个对象数组，因此必须从该数组获取CardSet：

query.findObjectsInBackgroundWithBlock { (objects, error) -> Void in
    if (error == nil) {
        for object in objects { //note: if objects is always of size 1, just use objects[0]
            var cardset = object as CardSet //get the entry
            var lesson = cardset.lesson
        }
    }else{
        println(error.userInfo)
    }
})

Answer 3

首先，您必须使用includekey，然后在findobjectwithdatablock中将数据另存为PFObject->如果数据为PFUser，另存为PFUser，否则另存为PFObject

范例：

var veriable  = (PFUser)() 
YourQueryFindObjectBlock {  
self.veriable = result["pointerCol"] as PFUser // if pointer has user data 
}