ios - Swift3/Firebase 更新子项

Question

//问题已解决我自己发现了它，仍然感谢您的帮助:=)

我尝试构建一个类似 Instagram 的应用程序用于学习目的。我可以从 Firebase 上传和检索数据。当我上传新图片时，我将评论值设置为0。因此，当用户发表评论时，我想更新子项(“kommentAnzahl”)的值+1表示新评论，负-1表示删除的评论(删除还不重要)。这样我就可以让我的标签 anzahlKommentare 在每个帖子下方显示用户的评论数量(就像 Instagram 一样)

我的完整代码在下面

class MemesTableViewController: UITableViewController {

var kommentarArray = [FotoComment]()
var dataBaseRef : FIRDatabaseReference!
var storageRef : FIRStorageReference!
var posts = [PostMitBild]()
var segmentedControl : HMSegmentedControl!

override func viewDidLoad() {
    super.viewDidLoad()

segmentedControl = HMSegmentedControl(sectionTitles: ["Top Heute", "Beliebteste", "Neue"])
  segmentedControl.frame = CGRect(x: 10, y: 10, width: 300, height: 60)
    segmentedControl.backgroundColor = UIColor.red
    segmentedControl.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
    segmentedControl.borderColor = UIColor.brown
    segmentedControl.tintColor = UIColor.black
    segmentedControl.selectionIndicatorColor = UIColor.gray


    segmentedControl.addTarget(self, action: #selector(getter: MemesTableViewController.segmentedControl), for: UIControlEvents.valueChanged)
    tableView.tableHeaderView = segmentedControl

 segmentedAction()
}

func segmentedAction() {
    if segmentedControl.selectedSegmentIndex == 0 {

        let postRef = FIRDatabase.database().reference().child("MemesBilder")

        postRef.observe(.value, with: { (snapshot) in
            var newPost = [PostMitBild]()
            for post in snapshot.children {

                let Post = PostMitBild(snapshot: post as! FIRDataSnapshot)
                newPost.insert(Post, at: 0)

            }

            self.posts = newPost
            DispatchQueue.main.async {

                self.tableView.reloadData()


            }

            }, withCancel: { (error) in
                print(error.localizedDescription)
        })

    }

}

//------------------------------------------

override func viewWillAppear(_ animated: Bool) {

    if FIRAuth.auth()?.currentUser == nil {

        let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "Login")
        self.present(vc, animated: true, completion: nil)

    }

}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "postCell", for: indexPath) as! PostTableViewCell

    if let seconds = posts[indexPath.row].postDate {
         let timestamp = NSDate(timeIntervalSince1970: seconds)

        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "dd/MM/yyyy  HH:mm"
        cell.uploadDatum.text = dateFormatter.string(from: timestamp as Date)

    }

        cell.kommentarZähler.text = String(posts[indexPath.row].kommentarAnzahl)
        cell.usernameTextField.text = posts[indexPath.row].username
        cell.postContent.text = posts[indexPath.row].content


        storageRef = FIRStorage.storage().reference(forURL: posts[indexPath.row].userImageUrlString)
        storageRef.data(withMaxSize: 1 * 1024 * 1024, completion: { (data, error) in
            if error == nil {
                DispatchQueue.main.async {
                    if let data = data {
                        cell.UserImageView.image = UIImage (data: data)
                    }
                }

            }else {
                print(error?.localizedDescription)
            }
        })

        let storageRef2 = FIRStorage.storage().reference(forURL: posts[indexPath.row].PostImageUrlString)
        storageRef2.data(withMaxSize: 1 * 1024 * 1024, completion: { (data, error) in
            if error == nil {
                DispatchQueue.main.async {
                    if let data = data {

                        cell.postImageView.image = UIImage (data: data)
                    }

                }
            }else {
                print(error?.localizedDescription)
            }
        })

        return cell

}

//done!!!! ------------------------------------------

override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == .delete {
      tableView.deleteRows(at: [indexPath], with: .fade)


        let ref = posts[indexPath.row].ref
        ref!.removeValue()

        posts.remove(at: indexPath.row)
        tableView.deleteRows(at: [indexPath], with: .fade)

    }
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    var numberOfRows = 0
    switch segmentedControl.selectedSegmentIndex {
    case 0 :  numberOfRows = posts.count

    case 1: numberOfRows = posts.count

    default: break


    }

    return numberOfRows
}

override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 420.00
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segmentedControl.selectedSegmentIndex == 0 {
        if segue.identifier == "addComment" {
            let vc = segue.destination as! CommentTableViewController
            let indexPath = tableView.indexPathForSelectedRow!

            vc.selectedPosts = posts[indexPath.row]
        }

    }
}

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    if segmentedControl.selectedSegmentIndex == 0 {
        performSegue(withIdentifier: "addComment", sender: self)
    }
    if segmentedControl.selectedSegmentIndex == 1 {
        performSegue(withIdentifier: "addComment", sender: self)
    }
    if segmentedControl.selectedSegmentIndex == 2 {
        performSegue(withIdentifier: "addComment", sender: self)
    }
}

}



import UIKit
import Firebase
import FirebaseAuth
import FirebaseDatabase
import FirebaseStorage

class CommentTableViewController: UITableViewController {

    @IBOutlet weak var komentarZähler: UILabel!
    @IBOutlet weak var UserImageView: UIImageView!
    @IBOutlet weak var usernameTextField: UILabel!
    @IBOutlet weak var postImageView: UIImageView!
    @IBOutlet weak var postContent: UITextView!

    var dataBaseRef : FIRDatabaseReference!
    var storageRef : FIRStorageReference!
    var commentsArray = [FotoComment]()
    var selectedPosts:PostMitBild!
    var DataBaseRef : FIRDatabaseReference! {
    return FIRDatabase.database().reference()
    }

    override func viewDidLoad() {
    super.viewDidLoad()
    configurePost()

    let commentRef = selectedPosts.ref!.child("Kommentare")

    commentRef.observe(.value, with: { (snapshot) in
        var newComments = [FotoComment]()
        for item in snapshot.children {
            let neuerKommentar = FotoComment(snapshot: item as! FIRDataSnapshot)
            newComments.insert(neuerKommentar, at: 0)

        }
        self.commentsArray = newComments
        self.tableView.reloadData()

        }, withCancel: { (error) in
            print(error.localizedDescription)
    })

    }
    @IBAction func addComment(_ sender: UIBarButtonItem) {

    let alertView = UIAlertController(title: "Kommentar", message: "Füge einen Kommentar hinzu", preferredStyle: UIAlertControllerStyle.alert)
    alertView.addTextField { (textfield) in
        textfield.placeholder = "Einen neuen Kommentar hinzufügen"

    }

    let sendCommentAction = UIAlertAction(title: "Kommentieren", style: .default) { (action) in
        let textfield = alertView.textFields!.first!

        let comment = FotoComment(content: textfield.text! , postId: self.selectedPosts.postId , username: (FIRAuth.auth()!.currentUser!.displayName!) , userImageUrlString: String(describing: FIRAuth.auth()!.currentUser!.photoURL!), postDate: (NSDate().timeIntervalSince1970))

        let commentRef = self.selectedPosts.ref!.child("Kommentare").childByAutoId()

        let myReference = FIRDatabase.database().reference()
      myReference.child("MemesBilder").child("kommentarAnzahl").setValue(["kommentarAnzahl": 1])

        commentRef.setValue(comment.toAnyObject())

        // commentRef.child("kommentarAnzahl").updateChildValues(["kommentarAnzahl" : 1])

    }

    let cancelAction = UIAlertAction(title: "Abbrechen", style: .cancel, handler: nil)
    alertView.addAction(sendCommentAction)
    alertView.addAction(cancelAction)
    self.present(alertView, animated: true, completion: nil)

    }

    // 2----------------------------------------------

    func configurePost() {

    usernameTextField.text = selectedPosts.username
    postContent.text = selectedPosts.content


    storageRef = FIRStorage.storage().reference(forURL: selectedPosts.userImageUrlString)
    storageRef.data(withMaxSize: 1 * 1024 * 1024, completion: { (data, error) in
        if error == nil {
            DispatchQueue.main.async {
                if let data = data {
                    self.UserImageView.image = UIImage (data: data)
                }
            }

        }else {
            print(error?.localizedDescription)
        }
    })
    let storageRef2 = FIRStorage.storage().reference(forURL: selectedPosts.PostImageUrlString)
    storageRef2.data(withMaxSize: 1 * 1024 * 1024, completion: { (data, error) in
        if error == nil {
            DispatchQueue.main.async {
                if let data = data {

                    self.postImageView.image = UIImage (data: data)
                }

            }
        }else {
            print(error?.localizedDescription)
        }
    })

    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
      komentarZähler.text = "Kommentare: \(commentsArray.count)"

    return commentsArray.count

    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "commentCell", for: indexPath) as! CommentTableViewCell

    if let seconds = commentsArray[indexPath.row].postDate {
        let timestamp = NSDate(timeIntervalSince1970: seconds)

        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "dd/MM/yyyy  HH:mm:ss"
        cell.uploadDatum.text = dateFormatter.string(from: timestamp as Date)

    }

    cell.usernameTextField.text = commentsArray[indexPath.row].username
    cell.postContent.text = commentsArray[indexPath.row].content

    storageRef = FIRStorage.storage().reference(forURL: commentsArray[indexPath.row].userImageUrlString!)
    storageRef.data(withMaxSize: 1 * 1024 * 1024, completion: { (data, error) in
        if error == nil {
            DispatchQueue.main.async {
                if let data = data {
                    cell.UserImageView.image = UIImage (data: data)
                }
                self.tableView.reloadData()
            }


        }else {
            print(error?.localizedDescription)
        }

    })
  return cell
}

}

import UIKit
import Firebase
import FirebaseStorage
import FirebaseAuth
import FirebaseDatabase

class AddImageViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate, UIPickerViewDelegate {

    @IBOutlet weak var postImage: UIImageView!

    @IBOutlet weak var textView: UITextView!

    var dataBaseRef : FIRDatabaseReference! {
    return FIRDatabase.database().reference()
    }

    var storageRef : FIRStorageReference! {
    return FIRStorage.storage().reference()
    }

    override func viewDidLoad() {
    super.viewDidLoad()

    }

    @IBAction func chooseImage(_ sender: UIButton) {
    let pickerController = UIImagePickerController()
    pickerController.delegate = self
    pickerController.allowsEditing = true

    let alertController = UIAlertController(title: "Bild aussuchen", message: "Suche dir dein neues Profilbild aus", preferredStyle: .actionSheet)

    let cameraAction = UIAlertAction(title: "Kamera", style: .default, handler: { (action) in
        pickerController.sourceType = .camera
        self.present(pickerController, animated: true, completion: nil)
    })
    let photoLibraryAction = UIAlertAction(title: "Fotoalbum", style: .default, handler: { (action) in
        pickerController.sourceType = .photoLibrary
        self.present(pickerController, animated: true, completion: nil)

    })
    let safedPhotoAction = UIAlertAction(title: "Fotos", style: .default, handler: { (action) in
        pickerController.sourceType = .savedPhotosAlbum
        self.present(pickerController, animated: true, completion: nil)

    })

    let cancelAction = UIAlertAction(title: "Abbrechen", style: .destructive, handler: nil)
    alertController.addAction(cameraAction)
    alertController.addAction(photoLibraryAction)
    alertController.addAction(safedPhotoAction)
    alertController.addAction(cancelAction)

    present(alertController, animated: true, completion: nil)

    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    let image = info[UIImagePickerControllerOriginalImage] as! UIImage
    self.postImage.image = image

    self.dismiss(animated: true, completion: nil)
    }

    @IBAction func SafeAction(_ sender: UIBarButtonItem) {
    let data = UIImageJPEGRepresentation(self.postImage.image!, 0.5)
    let metadata = FIRStorageMetadata()
    metadata.contentType = "image/jpeg"
    let postId = "\(FIRAuth.auth()!.currentUser!.uid)\(NSUUID().uuidString)"
    let imagePath = "postIMAGES\(postId)/postPic.jpg"

    storageRef.child(imagePath).put(data!, metadata: metadata) { (metadata, error) in
        if error == nil {

            let postRef = self.dataBaseRef.child("MemesBilder").childByAutoId()
            let post = PostMitBild(content: self.textView.text!, postId: postId, username: (FIRAuth.auth()?.currentUser?.displayName!)!, PostImageUrlString: String(describing: metadata!.downloadURL()!), userImageUrlString: String(describing: FIRAuth.auth()!.currentUser!.photoURL!), postDate: (NSDate().timeIntervalSince1970), kommentarAnzahl: 0)

                postRef.setValue(post.toAnyObject())


            let vc =  UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "Memes")
            self.present(vc, animated: true, completion: nil)


        }else {
            print(error!.localizedDescription)
        }
    }
       _ = navigationController?.popToRootViewController(animated: true)
    }

}

这些是我的 3 个 VC，用于显示图片 (MemesTableView)、用于添加图片 (AddImageView) 和用于评论上传的图片 (CommentTableView)

下面是我的 Firebase 结构的样子

这就是我的结构的样子

我想在每次用户评论时将函数“addComment”中的投票数更新为 1

This is my JSON Tree in written format

Answer 1

• 我给出了一个用于更新 firebase 中投票计数值的示例函数。尝试以下方法

  func adddComment() {
    dataBaseRef.child("MemesBilder").child(userId).child("anzahlKommentare").runTransactionBlock({ (currentData: FIRMutableData) -> FIRTransactionResult in
      var voteCount = currentData.value as? Double
      if (voteCount == nil) {
          voteCount = 0
      }
      currentData.value = voteCount! + 1
      return FIRTransactionResult.successWithValue(currentData)
  }) 
  }
  

  • 您还可以找到补全https://firebase.google.com/docs/database/ios/read-and-write