Firebase swift中的“赞”按钮

Question

我正在尝试为我的 UITableViewCell 创建一个赞按钮。到目前为止，我设法做的是每次单击按钮时用 +1 更新喜欢的数量。但是，我只希望用户能够按一次按钮，如果同一用户再次单击该按钮，则用户不喜欢该帖子-就像 facebook 喜欢按钮一样。

如果有任何帮助，我将通过 facebook 登录我的应用程序。

我的代码：

@IBAction func likeTapped(sender: AnyObject) {
        //print(pathDB)
        FIRDatabase.database().reference().child("feed-items").child(pathDB).observeSingleEventOfType(.Value, withBlock: { (snapshot) in
            // Get user value
            let antalLikes = snapshot.value!["likesForPost"] as! Int
            print(antalLikes)
            let dataPathen = self.pathDB
            print(dataPathen)

                self.updateTotalNoOfPost{
                    print("Updated")
                }

            // ...
        }) { (error) in
            print(error.localizedDescription)
        }
    }

    func updateTotalNoOfPost(completionBlock : (() -> Void)){

        let prntRef = FIRDatabase.database().reference().child("feed-items").child(pathDB).child("likesForPost")

        prntRef.runTransactionBlock({ (resul) -> FIRTransactionResult in
            if let dealResul_Initial = resul.value as? Int{

                resul.value = dealResul_Initial + 1
                //Or HowSoEver you want to update your dealResul.
                return FIRTransactionResult.successWithValue(resul)
            }else{
                return FIRTransactionResult.successWithValue(resul)
            }
            }, andCompletionBlock: {(error,completion,snap) in

                print(error?.localizedDescription)
                print(completion)
                print(snap)
                if !completion {
                    print("Couldn't Update the node")
                }else{
                    completionBlock()
                }
        })
    }

这里有我在 firebase 中的结构：

希望你们能帮助我:)

Answer 1

如果你的 JSON 是这样的：-

{
  feed-items: {
     feedItem1 :{
          feedText : "This is feed1",
          feedLikes : {uid1 : "true",
                       uid2 : "true"
                    }   
           },
       feedItem2 :{
          feedText : "This is feed2",
          feedLikes : {uid13 : "true",
                       uid2 : "true"
                    }   
           },
         feedItem3 :{
          feedText : "This is feed4",
          feedLikes : {uid4 : "true",
                       uid10 : "true"
                    }   
           },
      }
  }

在检索之前，您必须检查用户是否已经喜欢这篇文章，并相应地设置点赞按钮的状态：-

用于存储检索到的字典使用：-

struct feed {

    var feedLikes : NSMutableDictionary!
    var feedText : String!
    var doILikeThisPost : Bool!
    var feedNameI : String!

    init(likes:NSMutableDictionary!, feed : String!, likeTisPost : Bool!, feedNM : String!){

        self.doILikeThisPost = likeTisPost
        self.feedLikes = likes
        self.feedText = feed
        self.feedNameI = feedNM
    }

}

在你的 tableViewController 中：-

import UIKit
import Firebase
class customTableViewController : UIViewController, UITableViewDelegate ,UITableViewDataSource{


var feedD = [feed]()
@IBOutlet wear var customTableView : UITableView!


override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)
    customTableView.delegate = self
     customTableView.dataSource = self
    retrieveTheData()


}





func retrieveTheData(){

    FIRDatabase.database().reference().child("feed-items").observeSingleEventOfType(.Value, withBlock: {(allFeeds) in

        if let feedDict = allFeeds.value as? [String: AnyObject]{

            for each in feedDict{

                if let feedLikesDict = each.1["feedLikes"] as? NSMutableDictionary{

                    if feedLikesDict[currentUerID] != nil{

                        let temp = feed.init(likes: feedLikesDict, feed: each.1["feedText"] as! String, likeTisPost: true, feedNM : each.0)
                        self.feedD.insert(temp, atIndex: 0)
                        self.customTableView.reloadData()
                    }else{

                        let temp = feed.init(likes: feedLikesDict, feed: each.1["feedText"] as! String, likeTisPost: false, feedNM : each.0)
                        self.feedD.insert(temp, atIndex: 0)
                        self.customTableView.reloadData()
                    }
                }else{

                    let temp = feed.init(likes: nil, feed: each.1["feedText"] as! String, likeTisPost: false, feedNM : each.0)
                    self.feedD.insert(temp, atIndex: 0)
                    self.customTableView.reloadData()

                }

            }
        }

    })
}




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

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return feedD.count ?? 0
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = self.customTableView.dequeueReusableCellWithIdentifier("CELL") as! customCell

    if feedD[indexPath.row].doILikeThisPost == true{

        cell.feedLikeBtn.selected = true
        cell.feedTextPost = feedD[indexPath.row].feedText
        cell.feedName = feedD[indexPath.row].feedNameI
        cell.parentTableViewController = self
        cell.indexPathForRow = indexPath.row
    }else{

        cell.feedLikeBtn.selected = false
        cell.feedTextPost = feedD[indexPath.row].feedText
        cell.feedName = feedD[indexPath.row].feedNameI
        cell.parentTableViewController = self
         cell.indexPathForRow = indexPath.row
    }


    return cell
    }



}

你自定义的TableViewCell：-

class customCell : UITableViewCell{

@IBOutlet weak var feedLikeBtn : UIButton!
var feedTextPost = String()
var feedName = String()
var indexPathForRow : Int!


var parentTableViewController : customTableViewController!

@IBAction func likeBtn(sender:UIButton!){

    if sender.selected == false{

        FIRDatabase.database().reference().child("feed-items").child(feedName).child("feedLikes").updateChildValues([currentUserID : "true"])
        self.parentTableViewController.feedD[self.indexPathForRow].feedLikes.setObject("true", forKey: currentUserID)
        self.parentTableViewController.feedD[self.indexPathForRow].doILikeThisPost = true
        self.parentTableViewController.customTableView.reloadData()


    }else if sender.selected == true{

        FIRDatabase.database().reference().child("feed-items").child(feedName).child("feedLikes").child(currentUserID).removeValue()
        self.parentTableViewController.feedD[self.indexPathForRow].feedLikes.removeObjectForKey(currentUserID)
        self.parentTableViewController.feedD[self.indexPathForRow].doILikeThisPost = false
        self.parentTableViewController.customTableView.reloadData()

        }


    }

}

另见：-https://stackoverflow.com/a/39458044/6297658