Swift instagram 克隆：加载关注的用户帖子

Posted 2023-03-10

【中文标题】Swift instagram 克隆：加载关注的用户帖子

【英文标题】：Swift instagram clone : loading followed user post

【发布时间】：2014-09-11 22:14:02

【问题描述】：

我正在尝试基于 Ribbit tuto 用 swift 制作一个 instagram 克隆。人们可以分享照片并关注其他用户等。我使用 Parse 在用户之间创建了PFRelation。我现在想做的是显示在我的WalltableViewController，只有关注的用户发布。

我创建了一个函数来将所有帖子加载到一个名为 timeLineData 的 NSMutable 数组中。

我什至制作了一个函数来获取 NSMutableArray 的关注用户，称为 followedFriends..

但我没有成功使用followedFriends 过滤加载帖子功能。我有这个错误：Terminating app due to uncaught exception 'NSInvalidArgumentException'，原因：'Cannot do a comparison query for type: __NSArrayM'

这是我的代码：

 import UIKit
 import QuartzCore

class WallTableViewController: UITableViewController, UINavigationControllerDelegate 

  @IBOutlet var posterAvatar: UIImageView!

   override func preferredStatusBarStyle() -> UIStatusBarStyle 
    return UIStatusBarStyle.LightContent
    


     var timeLineData:NSMutableArray = NSMutableArray ()
    var followedFriends:NSMutableArray = NSMutableArray ()

     func loadUser () 

    followedFriends.removeAllObjects()
    var friendsRelation: AnyObject! = PFUser.currentUser().objectForKey("KfriendsRelation")


var findUser : PFQuery = friendsRelation.query()


findUser.findObjectsInBackgroundWithBlock  (objects:[AnyObject]!, error:NSError!) -> Void in
    if !(error != nil) 
        // The find succeeded.
        println("succesfull load Users")
        // Do something with the found objects
        for object  in objects  
            self.followedFriends.addObject(object)
            println("users added to userlist")

            for item in self.followedFriends 
                println(item)                    
        
        self.tableView.reloadData()
     else 
        // Log details of the failure
        println("error loadind user ")

    

   
  


   func loadPost () 

  timeLineData.removeAllObjects()

   let currentUser = PFUser.currentUser()

    var findPost:PFQuery = PFQuery(className: "UserPost")


   findPost.whereKey("from", equalTo: followedFriends )


    findPost.orderByDescending("createdAt")


    findPost.findObjectsInBackgroundWithBlock 
        (objects: [AnyObject]! , error: NSError!) -> Void in
        if !(error != nil) 
            // The find succeeded.
            println("current user post finded")
            // Do something with the found objects
            for object  in objects  
                self.timeLineData.addObject(object)
            
            self.tableView.reloadData()
         else 
            // Log details of the failure
            println("error loadind user post")
        


    




 override func numberOfSectionsInTableView(tableView: UITableView) -> Int 
return 1


 override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int 
return timeLineData.count


 override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell 

    let cell:WallTableViewCell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as WallTableViewCell

   let userPost:PFObject = self.timeLineData.objectAtIndex(indexPath.row) as PFObject

//define the username

var findUser:PFQuery = PFUser.query()
findUser.whereKey("objectId", equalTo: userPost.objectForKey("from").objectId)

findUser.findObjectsInBackgroundWithBlock
    (objects:[AnyObject]!, error:NSError!) -> Void in

    if !(error != nil) 
        if let user:PFUser = (objects as NSArray).lastObject as? PFUser 
            cell.usernameLabel.text = user.username

            // define avatar poster

               if let avatarImage:PFFile = user["profileImage"] as? PFFile 
                avatarImage.getDataInBackgroundWithBlock(imageData:NSData!, error:NSError!)->    Void in

                    if !(error != nil) 

                        let image:UIImage = UIImage(data: imageData)


                        cell.posterAvatar.image = image as UIImage
                        cell.posterAvatar.layer.cornerRadius = 24
                        cell.posterAvatar.clipsToBounds = true

                    

                
            
            else 
                cell.posterAvatar.image = UIImage(named: "Avatar-1")
                cell.posterAvatar.layer.cornerRadius = 24
                cell.posterAvatar.clipsToBounds = true
            
        

    



//define the imagepost

let imagesPost:PFFile = userPost["imageFile"] as PFFile


imagesPost.getDataInBackgroundWithBlock(imageData:NSData!, error:NSError!)-> Void in

    if !(error != nil) 

        let image:UIImage = UIImage(data: imageData)

        cell.imagePosted.image = image as UIImage


    
    else 
        println("error")
    
  


      return cell
     


  override func viewDidAppear(animated: Bool) 
     var currentUser = PFUser.currentUser()
       if (currentUser != nil) 
     println("User allready logued")
      

    else 
    // Show the signup or login screen

    self.performSegueWithIdentifier("goToLogIn", sender: self)
    

    


  override func viewWillAppear(animated: Bool) 
   self.tableView.separatorColor = UIColor.whiteColor()

   tabBarController?.tabBar.tintColor = UIColor.whiteColor()
   self.loadUser()
  self.loadPost()
   self.tableView.reloadData()

  
  

【问题讨论】：

这一行的错误是：findPost.whereKey("from", equalTo: followFriends) 吗？因为看起来您正在尝试将单个字段的值与整个数组进行比较。

【参考方案1】：

FollowedFriends 是一个数组，所以你需要使用containedIn。如果您要与一个单独的对象进行比较，则使用 equalTo。改成这个。

findPost.whereKey("from", containedIn:followedFriends)

【参考方案2】：

我也创建了这个解决方案：

   //query for the friends of the user
var friendsRelation: AnyObject! = PFUser.currentUser().objectForKey("KfriendsRelation")
var findFriends : PFQuery = friendsRelation.query()

 //using the friends from the query above, we find all the posts of the friends of the current    user
var findPosts:PFQuery = PFQuery(className: "UserPost")
findPosts.whereKey("from", matchesQuery:findFriends)
findPost.orderByDescending("createdAt")

 //run the query
 findPosts.findObjectsInBackgroundWithBlock  (objects:[AnyObject]!, error:NSError!) -> Void in
    if !(error != nil) 
        //found posts

        self.tableView.reloadData()
     else 
        // Log details of the failure
        println("error loadind posts ")