数据解析后重新加载UICollection视图 [英] Reloading UICollection view after data parse

问题描述

我正在尝试动态更新uicollectionview.我使用了这本很棒的教程，以了解如何创建一个简单的uicollection.

I am trying to dynamically update a uicollectionview. I used this amazing tutorial on how to create a simple uicollection.

在使用静态项目数组时，它非常有用.我的问题-我想用从数据库中解析为新数组的数据填充uicollection.我不确定解析json数据后如何重新加载uicollection.

It works great when using a static array of items. My issue - I would like to have the uicollection populate with data I parsed into a new array from my db. I am not sure how to reload the uicollection after parsing my json data.

使用答案更新代码:

import UIKit

class Books: UIViewController, UICollectionViewDelegate {

    @IBOutlet weak var bookscollection: UICollectionView!

    var user_id: Int = 0;

    //------------ init ---------------//

    override func viewDidLoad() {
        super.viewDidLoad()

    }

    override func viewDidAppear(_ animated: Bool) {
        showtutorial()
        getuserid()
    }


    //------------ show books ---------------//

    var booknames = [String]()
    var bookcolor = [String]()
    var bookdescription = [String]()
    var bookid = [Int]()

    func posttoapi(){

        //show loading
        LoadingOverlay.shared.showOverlay(view: self.view)

        //send
        let url:URL = URL(string: "http://www.url.com")!
        let session = URLSession.shared
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
        request.cachePolicy = NSURLRequest.CachePolicy.reloadIgnoringCacheData
        let paramString = "user_id=\(user_id)"
        request.httpBody = paramString.data(using: String.Encoding.utf8)

        let task = session.dataTask(with: request as URLRequest) {(data, response, error) in

            //hide loading
            LoadingOverlay.shared.hideOverlayView()

            //no response
            guard let data = data, let _:URLResponse = response, error == nil else {
                print("response error")
                return
            }

            //response, parse and send to build
            let json = String(data: data, encoding: String.Encoding.utf8);
            if let data = json?.data(using: String.Encoding.utf8){

                let json = try! JSON(data: data)

                for item in json["rows"].arrayValue {

                    //push data to arrays
                    self.booknames.append(item["name"].stringValue)
                    self.bookcolor.append(item["color"].stringValue)
                    self.bookdescription.append(item["description"].stringValue)
                    self.bookid.append(item["id"].int!)

                    //reload uicollection 
                    DispatchQueue.main.sync(execute: {
                        self. bookscollection.reloadData()  
                    })


                }

            }

        }

        task.resume()

    }




    //------------ collection -------------//

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

        print("collection view code called")
        return self.booknames.count
    }


    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = bookscollection.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath as IndexPath) as! BooksCell
        cell.myLabel.text = self.booknames[indexPath.item]
        cell.backgroundColor = UIColor.cyan // make cell more visible in our example project
        return cell
    }


    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        print("You selected cell #\(indexPath.item)!")
    }



    //------------ end ---------------//

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }


}

谢谢您的帮助！

推荐答案

我遇到了同样的问题..您的网址中包含很多图片意味着重新加载t

Same problem i faced..your url having many images means reload t

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

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