swift - 使用 Unresolved 标识符错误对象

Question

我正在尝试从解析中的信息更新用户名标签。我无法弄清楚，并且已经为我苦苦挣扎了好一阵子了，这不起作用。

  let query = PFUser.query()!
    query.whereKey("objectId", equalTo: (quote["publisher"] as! String))
    query.getFirstObjectInBackgroundWithBlock({ (user: PFObject?, error: NSError?) in
            if error == nil{
            let user:PFUser = (objects as NSArray).lastObject as! PFUser//error here
            cell.publisherLabel.text = user.username
        }
    })

我得到的错误是使用未解决的标识符“对象”

Answer 1

您没有在该闭包中返回数组，而是要返回可选的PFObject。

 let query = PFUser.query()!
query.whereKey("objectId", equalTo: (quote["publisher"] as! String))
query.getFirstObjectInBackgroundWithBlock({ (user: PFObject?, error: NSError?) in
        if error == nil{
        if let foundUser = user as? PFUser {
        cell.publisherLabel.text = foundUser.username

    }
}
})

// 更新

func someFunc() {

    let query = PFUser.query()
    query?.getObjectInBackgroundWithId("objectId", block: { (foundUser: PFObject?, error: NSError?) -> Void in

        if let user = foundUser as? PFUser {

            cell.publisherLabel.text = user.username
        }

    })

}

您不需要查询，只需从您拥有的对象中获取指针，然后调用fetchIfNeeded或在后台调用，或者您想对其进行处理。例：

var myObject = existingObjectWithPointer["pointerColumnName"] as? PFObject
myObject.fetchIfNeeded()