Ios 在CellForRowatineXpath中使用PFQuery
我在考虑Ios 在CellForRowatineXpath中使用PFQuery,ios,swift,uitableview,parse-platform,pfquery,Ios,Swift,Uitableview,Parse Platform,Pfquery,我在考虑PFQuery 我正在开发一个向用户显示提要的应用程序,它还为每个帖子显示一个类似计数器(如Facebook应用程序或Instagram应用程序) 因此,在我的PFQueryTableViewController中,我有我的主查询,它基本上显示了所有帖子: override func queryForTable() -> PFQuery { let query = PFQuery(className: "Noticias") query.orderByDescend
PFQuery
我正在开发一个向用户显示提要的应用程序,它还为每个帖子显示一个类似计数器(如Facebook应用程序或Instagram应用程序)
因此,在我的PFQueryTableViewController
中,我有我的主查询,它基本上显示了所有帖子:
override func queryForTable() -> PFQuery {
let query = PFQuery(className: "Noticias")
query.orderByDescending("createdAt")
return query
}
我使用另一个查询来计算另一个类中的喜欢数,解析该类包含所有喜欢
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath, object: PFObject?) -> PFTableViewCell? {
var cell = tableView.dequeueReusableCellWithIdentifier("FeedCellIdentifier") as! FeedCell!
if cell == nil {
cell = FeedCell(style: UITableViewCellStyle.Default, reuseIdentifier: "FeedCellIdentifier")
}
let query2 = PFQuery(className:"commentsTable")
query2.whereKey("newsColumn", equalTo: object!)
query2.findObjectsInBackgroundWithBlock {
(objectus: [PFObject]?, error: NSError?) -> Void in
if error == nil {
let quantidade = objectus!.count
let commentQuantidade = String(quantidade)
cell.comentariosLabel.text = commentQuantidade
} else {
// Log details of the failure
print("Error: \(error!) \(error!.userInfo)")
}
}
这种编码方式有效,我实现了我想要的,但是!我知道我在重用单元格,我知道每当单元格出现时,这段代码都会被调用
我知道这些事实:
countobjectsinbackgroundithblock
,而不是findobjectsinbackgroundithblock
,但我无法将查询移动到ViewDidLoad,因为我使用对象
来检查每篇文章的评论数
编辑2
我嵌入了查询以计算每篇文章的评论数并打印结果,现在我认为我的代码比以前的版本更好,但我无法将结果传递给标签,因为我收到一个错误:
使用未解析的标识符“commentCount”
我正在阅读一些关于Struct
下面是我更新的代码:
import UIKit
import Social
class Functions: PFQueryTableViewController, UISearchBarDelegate {
override func shouldAutorotate() -> Bool {
return false
}
var passaValor = Int()
let swiftColor = UIColor(red: 13, green: 153, blue: 252)
struct PostObject{
let post : PFObject
let commentCount : Int
}
var posts : [PostObject] = []
// Initialise the PFQueryTable tableview
override init(style: UITableViewStyle, className: String!) {
super.init(style: style, className: className)
}
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)!
// The className to query on
self.parseClassName = "Noticias"
// The key of the PFObject to display in the label of the default cell style
self.textKey = "text"
// Uncomment the following line to specify the key of a PFFile on the PFObject to display in the imageView of the default cell style
self.imageKey = "image"
// Whether the built-in pull-to-refresh is enabled
self.pullToRefreshEnabled = true
// Whether the built-in pagination is enabled
self.paginationEnabled = true
// The number of objects to show per page
self.objectsPerPage = 25
}
// Define the query that will provide the data for the table view
override func queryForTable() -> PFQuery {
let query = super.queryForTable()
return query
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(true)
loadObjects()
}
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func viewDidLoad() {
super.viewDidLoad()
// navigationBarItems()
let query = PFQuery(className:"Noticias")
query.findObjectsInBackgroundWithBlock {
(objects: [PFObject]?, error: NSError?) -> Void in
// The find succeeded.
print("Successfully retrieved \(objects!.count) scores.")
// Do something with the found objects
if let objects = objects {
for object in objects {
let queryCount = PFQuery(className:"commentsTable")
queryCount.whereKey("newsColumn", equalTo: object)
queryCount.countObjectsInBackgroundWithBlock {
(contagem: Int32, error: NSError?) -> Void in
let post = PostObject(object, commentCount:commentCount)
posts.append(post)
print("Post \(object.objectId!) has \(contagem) comments")
}
self.tableView.reloadData()
}
}
}
//Self Sizing Cells
tableView.estimatedRowHeight = 350.0
tableView.rowHeight = UITableViewAutomaticDimension
}
// Define the query that will provide the data for the table view
//override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath, object: PFObject?) -> PFTableViewCell? {
var cell = tableView.dequeueReusableCellWithIdentifier("FeedCellIdentifier") as! FeedCell!
if cell == nil {
cell = FeedCell(style: UITableViewCellStyle.Default, reuseIdentifier: "FeedCellIdentifier")
}
cell?.parseObject = object
if let assuntoNoticia = object?["assunto"] as? String {
cell?.assuntoNoticia?.text = assuntoNoticia
}
if let pontos = object?["pontos"] as? Int {
let pontosPosts = String(pontos)
cell?.pontosLabel?.text = String(pontosPosts)
}
if let zonaLabel = object?["zona"] as? String {
cell?.zonaLabel?.text = zonaLabel
}
if let criticidade = object?["criticidade"] as? String {
if criticidade == "Problema"{
cell.criticidadeNoticia.backgroundColor = UIColor.redColor()
} else {
cell.criticidadeNoticia.backgroundColor = UIColor.greenColor()
}
}
return cell
}
}
打印结果:
成功检索到5个分数
Post wSCsTv8OnH有4条评论
发布LbwBfjWPod有0条评论
帖子fN4ISVwqpz有0条评论
帖子1rXdQr2A1F有1条评论
Post eXogPeTfNu有0条评论
在将信息显示在tableview中之前,您应该先进行查询。更好的做法是在加载视图时查询所有数据并将其保存到模型中,然后在“table view scroll”中从中读取数据。处理查询时,您可以显示正在下载的指示符或占位符数据。查询完成后,您将调用
tableView.reloadData()
您可以通过如下方式创建新变量来完成此操作:
var cellModels : [PFObject] = []
struct PostObject{
let post : PFObject
let commentCount : Int
}
var posts : [PostObject] = []
在查询2中。findObjectsInBackgroundWithBlock
:
for object in objectus{
self.cellModels.append(object)
}
self.tableView.reloadData()
并在单元格中按行索引路径
:
let model = cellModels[indexPath.row]
// configure cell according to model
// something like cell.textLabel.text = model.text
let post = posts[indexPath.row]
cell.postCountLabel.text = String(post.commentCount)
// configure cell accordingly
p.S如果您只需要获取对象的计数,您应该查看方法countObjectsInBackgroundWithBlock
。因为如果有很多注释,例如findObjectsInBackgroundWithBlock
将返回最多1000个对象,并且您仍然不会下载整个对象,只有一个数字,这将加快查询速度并节省用户的移动计划
更新:如果需要存储大量注释,也可以创建简单的结构
,如下所示:
var cellModels : [PFObject] = []
struct PostObject{
let post : PFObject
let commentCount : Int
}
var posts : [PostObject] = []
当您查询您的帖子时,您将循环接收到的对象并填充posts
array
for object in objects{
// create countObjectsInBackgroundWithBlock query to get comments count for object
// and in result block create
let post = PostObject(object, commentCount:commentCount)
posts.append(post)
}
tableView.reloadData()
并在单元格中按行索引路径
:
let model = cellModels[indexPath.row]
// configure cell according to model
// something like cell.textLabel.text = model.text
let post = posts[indexPath.row]
cell.postCountLabel.text = String(post.commentCount)
// configure cell accordingly
回答得很好,我正在尝试在我的代码中应用您所解释的内容,我将发布一个更新。我已经阅读了文档并改进了我的方法,将
countobjectsinbackgroundithblock
改为findobjectsinbackgroundithblock
,现在当我将查询移动到viewDidLoad时,我无法引用对象query2.whereKey(“newsColumn”,equalTo:object!)
对象是什么类型的object
?您在哪里分配它?是的,它看起来比开始时好多了。您应该将(contagage:Int32,error:NSError?)替换为(contagage:Int32,error:NSError?->Void in let post=PostObject(object,commentCount:commentCount)
(contagage:Int32,error:NSError?)->Void in let post=PostObject(object,commentCount:contagage)
请报告您的进度,我是来帮助您的。您的numberofrowsinssection
方法是什么?我会将返回帖子。count
放在那里。