ios - CollectionView 和 CompletionHandler

Question

我试图在加载数据后加载我的 CollectionView，但我不知道应该如何使用 CompletionHandler 来执行此操作。感谢帮助我的代码如下:用于获取数据:

func GETData(){

    urlString = "https://api.backendless.com/v1/data/Pub?pageSize=10&offset="+String(offset)
    let session = NSURLSession.sharedSession()
    let url = NSURL(string: urlString)!
    let request = NSMutableURLRequest(URL: url)

    request.setValue(applicationId, forHTTPHeaderField: "application-id")
    request.setValue(secretKey, forHTTPHeaderField: "secret-key")

    let task = session.dataTaskWithRequest(request, completionHandler: { (data: NSData?,response: NSURLResponse?, error: NSError?) in

        if let responseData = data
        {
            parseDATA(responseData)
        }

        })
    task.resume()

    offset+=(pubs.count-offset)
    urlString = "https://api.backendless.com/v1/data/Pub"
}

对于 colelectionView 加载:

override func viewDidLoad() {
        pubs.removeAll()
        GETData()
        super.viewDidLoad()
        typealias  UIActivityViewControllerCompletionHandler = () -> Void

        print("AKTUAL: "+String(pubs.count))
        collectionView.delegate = self
        collectionView.dataSource = self

        // Do any additional setup after loading the view.
    }

Answer 1

在服务调用的成功 block 末尾重新加载 Collection View ，如下所示

[collectionView reloadData];

您还可以在 URLSession 委托(delegate)中提供 reloadData 方法。