Nrthugu

I built my app to have news feed like Facebook. My problem is that I don't know how to fetch child images in Post and show it in a collectionView. Please show me how to do it. Appreciate any help.

Here is the db structure:

Posts

   d7j3bWMluvZ6VH4tctQ7B63dU4u1:

       20181112101928:

          avatar: "https://platform-lookaside.fbsbx.com/platform/p..."

          content: "Funny image"

          images:

              -LR4vaEIggkGekc-5ZME:

                       "https://firebasestorage.googleapis.com/v0/b/hon..."

              -LR4vaENC-IsePibQYxY:                             

                       "https://firebasestorage.googleapis.com/v0/b/hon..."

          name: "Thành Trung"

          time: 1541992768776.3628

          type: "Funny"

Here is my code:

   func getDataFromPostFirebase() {

        let getPostData = databaseReference.child("Posts")

        getPostData.observe(.childAdded) { (snapshot) in

            getPostData.child(snapshot.key).observe(.childAdded, with: { (snapshot1) in

                getPostData.child(snapshot.key).child(snapshot1.key).observe(.value, with: { (snapshot2) in

                    self.arrayImageUrl = [String]()

                    if let dict = snapshot2.value as? [String : Any] {

                        guard let avatar = dict["avatar"] as? String else {return}

                        guard let content = dict["content"] as? String else {return}

                        guard let name = dict["name"] as? String else {return}

                        guard let time = dict["time"] as? Double else {return}

                        guard let type = dict["type"] as? String else {return}

                        if let images = dict["images"] as? [String : String] {

                            for image in images.values {

                                self.arrayImageUrl.append(image)

                            }

                            let newPost = Post(avatarString: avatar, contentString: content, nameString: name, timeDouble: time, typeString: type)

                            self.arrayPost.append(newPost)

                            DispatchQueue.main.async {

                                self.feedTableView.reloadData()

                            }

                        } else {

                            let newPost = Post(avatarString: avatar, contentString: content, nameString: name, timeDouble: time, typeString: type)

                            self.arrayPost.append(newPost)

                            DispatchQueue.main.async {

                                self.feedTableView.reloadData()

                            }

                        }

                    }

                })

            })

        }

    }



    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

        return arrayImageUrl.count

    }



    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collectionViewCell", for: indexPath) as! TrangChu_CollectionViewCell



        cell.imgContent.layer.cornerRadius = CGFloat(8)

        cell.imgContent.clipsToBounds = true

        cell.imgContent.layer.borderWidth = 2

        cell.imgContent.layer.borderColor = #colorLiteral(red: 0.4756349325, green: 0.4756467342, blue: 0.4756404161, alpha: 1)



        let url = URL(string: arrayImageUrl[indexPath.row])

        cell.imgContent.sd_setImage(with: url, completed: nil)



        return cell

    }

Model object

import Foundation



class Post {

    var avatar : String

    var content : String

    var images : [String]?

    var name : String

    var time : Double

    var type : String



    init(avatarString : String, contentString : String, nameString : String, timeDouble : Double, typeString : String) {

        avatar = avatarString

        content = contentString

//        images = imagesString

        name = nameString

        time = timeDouble

        type = typeString

    }

}

As what I've said your db is not well structured. I suggest you re structure it like this.

Posts

   d7j3bWMluvZ6VH4tctQ7B63dU4u1:

      avatar: "https://platform-lookaside.fbsbx.com/platform/p..."

      content: "Funny image"

      images:

          -LR4vaEIggkGekc-5ZME: "https://firebasestorage.googleapis.com/v0/b/hon..."

          -LR4vaENC-IsePibQYxY: "https://firebasestorage.googleapis.com/v0/b/hon..."

      name: "Thành Trung"

      time: 1541992768776.3628

      type: "Funny"

      timestamp: 1540276959924

I removed the timestamp node and transferred it along the children node. Now you can fetch the posts with this.

ref.child("Posts").observe(.childAdded) { (snapshot) in

        var post = Post()



        let val = snapshot.value as! [String: Any]

        post.name = val["name"] as? String



        self.ref.child("Posts").child(snapshot.key).child("images").observeSingleEvent(of: .value, with: { (snap) in

            post.imagesString = [String]()

            for image in snap.children.allObjects as! [DataSnapshot] {

                post.imagesString?.append(image.value as! String)

                print("images (image.value)")

            }



            list.append(post)

            print("post (post)")

        })

If you want to order the posts you can achieve it using queryOrderedByChild("timestamp")

Add this to access your images:

guard let images = dict["images"] as? [[String: Any]] { return }

let imagesString: [String] = 

for imageDict in images {

    for key in imageDict.keys {

        if let imageName = imageDict[key] as? String else {

        // here you access your image as you want

            imagesString.append(imageName)

        }

    }   

}

Then when creating the post object you use imagesString that we created:

let newPost = Post(avatarString: avatar, contentString: content, imagesString: imagesString, nameString: name, timeDouble: time, typeString: type)

You can fetch the images values using this

ref.child("Posts").observe(.childAdded) { (snapshot) in



        self.ref.child("Posts").child(snapshot.key).observe(.childAdded, with: { (snapshot1) in

            self.ref.child("Posts").child(snapshot.key).child(snapshot1.key).child("images").observe(.childAdded, with: { (snap) in

                let post = new Post()

                for rest in snap.children.allObjects as! [DataSnapshot] {

                    //append images 

                    post.imagesString.append(rest.value)

                }





                post.avatarString = snapshot1.value["avatar"] as? String

                ...

            })

        })

I suggest you change the structure of your db because its nested. Refer here