CODEWITHSUNDEEP
arraysswiftimagefirebase-storage
Jiacai Lau
Jiacai Lau

Reputation: 72

Firebase Storage Async Image Download not in the right order

I am met with a problem when I tried to download a batch of images off firebase storage. Basically, because the file sizes differ, the images are not appended to the image array properly causing the images to be in the wrong order that I wanted. Below is the code

import Foundation
import FirebaseStorage

class GalleryCellDetailedData {
    var selectedGallery:String?
    var count:Int

    init(selectedGallery:String?,count:Int){
        self.selectedGallery = selectedGallery
        self.count = count
    }

    func addImages(completion:(data:[NSData])->()){
        var datas = [NSData]()
        let myGroup = dispatch_group_create()

        for i in 0..<count {
            dispatch_group_enter(myGroup)
            getImage(i, completion: { (image:NSData) in
                datas.append(image)
                print("Finish Request \(i)")
                dispatch_group_leave(myGroup)
            })
        }

        dispatch_group_notify(myGroup, dispatch_get_main_queue(), {
          completion(data: datas)
        })
    }

    private func getImage(number:Int, completion:(image:NSData)->()){
        let storage = FIRStorage.storage()

        //Reference to Firebase Profile Picture Storage
        let storageRef = storage.referenceForURL("gs://mannacatering-addcb.appspot.com")
        print("Initiating Image Download")

        let galleryPicRef = storageRef.child("Gallery/\(selectedGallery!)/g\(String(number)).jpg")

        //Download Image
        galleryPicRef.dataWithMaxSize(1 * 1024 * 1024) { (data, error) -> Void in
            if (error != nil) {
                print("fail to download image")
            }

            dispatch_async(dispatch_get_main_queue(), {
                print("Dispatching image")
                completion(image:data!)
            })
        }
    }
}

I split them up into 2 separate functions because I tried to manage them in a single function and the order is in a mess as well and I thought this might work but apparently not.

Upvotes: 0

Views: 934

Answers (2)

Mike McDonald
Mike McDonald

Reputation: 15963

I recommend taking an approach similar to Storing multiple images into firebase and getting urls, where you store the URLs in the Realtime Database, and use that as your source of truth for ordering, display, etc. It's far easier and makes for better apps :)

Upvotes: 0

Phillip Mills
Phillip Mills

Reputation: 31016

Instead of storing your data in an array, store it in a dictionary. The key can be the number i or however you want to refer to an image when you use it.

Upvotes: 2

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