array return empty when trying to call from outside the function [swift]

Question

I got this calling api function:

func searchResults(){


    let urlString = "http://dev.jocom.com.my/feed"


    Alamofire.request(.POST, urlString , parameters: ["req" : "pro_name", "code" : searchString!])

        .responseData { response in

            switch response.result {
            case .Success:

                let apiSearchXML = SWXMLHash.parse(response.data!)

                for elem in apiSearchXML["rss"]["channel"]["item"]{
                    self.imageURL.append(elem["thumb_1"].element!.text!)

                    self.name.append(elem["name"].element!.text!)



                }
                print(self.name)

            case .Failure(let error):
                print(error)
            }
    }

}

It seems ok when i print the output out, the array its containing something. But when i try to call it to display inside my collection view, it didnt return row, and it become empty, why is it?

func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {

    return 1
}


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

    return self.name.count

}


func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath) as! SearchResultsCollectionViewCell

    cell.titleLabel.text = "abc"
    cell.setNeedsDisplay()
    return cell
}

The Alamofire Readme explicitly mentions that request are performed *asynchronously*. Have a look at the frequently asked [alamofire] questions: This has been asked and answered repeatedly. — Martin R, Jul 18 '16 at 14:56

score 2 · Accepted Answer · answered Jul 18 '16 at 14:42

2

You need a completion handler for your Async call to complete and then you can fill the array with the results. I believe your name is an array of strings. Do like so:

func searchResults(complete: (names: [String]) -> ()){
let aVar = [String]()
//your code
for elem in apiSearchXML["rss"]["channel"]["item"]{

aVar.append(elem["name"].element!.text!)
}
complete(names: aVar)
//your code
}

Then when you call it, like so:

searchResults { theNames in
 print(theNames)
//Here you have your array of names, use how you want.
}

answered Jul 18 '16 at 14:42

Mtoklitz113

3,828
3
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it works! thankyou so muchhhh :D – minimomo Jul 18 '16 at 14:49
Glad to help. Happy coding! :) – Mtoklitz113 Jul 18 '16 at 14:49

fiks · Answer 2 · 2016-07-18T14:42:32.247

0

You should call

dispatch_async(dispatch_get_main_queue()) { 
   collectionView.reloadData()
}

when you get a callback from the server.

edited Jul 18 '16 at 14:42

answered Jul 18 '16 at 14:22

fiks

1,045
9
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where should i add it? – minimomo Jul 18 '16 at 14:24
right before `print(self.name)` – fiks Jul 18 '16 at 14:27
no, its still not working – minimomo Jul 18 '16 at 14:30
Did you run it on main thread? If not, you can try this: `dispatch_async(dispatch_get_main_queue(), ^{ collectionView.reloadData() // update some UI });` – fiks Jul 18 '16 at 14:32
what should i do with the update some ui part? – minimomo Jul 18 '16 at 14:37
I have updated my answer. Put this code right before `print(self.name)` – fiks Jul 18 '16 at 14:43

score 0 · Answer 3 · answered Jul 18 '16 at 14:25

0

"Networking in Alamofire is done asynchronously."

This means that your request will complete some unknown amount of time after you call searchResults.

Your best strategy is to update your collection view within your success block. (Make sure you make UI updates on the main thread.)

answered Jul 18 '16 at 14:25

Phillip Mills

30,888
4
42
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how should i do it? sorry, im very new in swift – minimomo Jul 18 '16 at 14:27
can provide me any example? – minimomo Jul 18 '16 at 14:28

array return empty when trying to call from outside the function [swift]

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