UITableView刷新与NSURLConnection异步加载的NSMutableArray的问题 [英] UITableView refresh problems with an NSURLConnection-asynchronously laden NSMutableArray

问题描述

我目前正在使用Swift(我已经在Objective-C中进行编码多年了)，并且正在尝试为我的视频监控系统开发一个配套应用.

I am currently approaching Swift (I have been coding in Objective-C for some years) and I am trying to develop a companion app to my video-surveillance system.

我的应用程序做什么:

1. 连接到受密码保护的网站，并获取由三个现有IP摄像机之一上传的最新快照的列表.
2. 对于每个镜头，我都会创建一个带有临时图片的PicInfo对象.然后，我尝试异步下载图片并将其存储在UIImage属性中.
3. 从那里，我的MasterViewController中有原型单元，其中包含一些细节.轻触一个按钮将使我在DetailViewController中看到一个更大的视图.

我还实现了刷新，在该刷新中，我将重新加载完整列表并替换最后100个表单元格和NSMutable数组的内容.

I also implemented a refresh where I'd reload the complete list and replace the last 100 table cells and the contents of the NSMutable array.

当前问题:

1. 初始加载后，主表视图显示为空，直到我轻轻触摸它为止.
2. 尽管NSLog ^ Wprintln语句显示列表已成功重新加载，但该表将不会刷新，并且仍将显示正在等待的小部件...
3. 在将NSData放入UIImages时，我得到了一些毫无用处的坏包装"错误(或者，我认为:mssage不太明确)，否则显示效果很好.

我在做什么错了?

PicInfo.swift

import Foundation
import UIKit

class PicInfo {
    var index: Int = 0
    var description: String = ""
    var stamp: String = ""
    var url: String = ""
    var image: UIImage!
    var downloaded: Bool = false;
    var downloading: Bool = false;

    init(data: String) {
        var picInfos=data.componentsSeparatedByString("\t")
        println("found: \(picInfos[0]): [\(picInfos[2])] taken at \(picInfos[1])")
        self.index = picInfos[0].toInt()!
        self.url = baseUrlString + "/" + picInfos[2]
        self.stamp = picInfos[1]
        description = ""
        if (picInfos[2].rangeOfString("HALLCAM") != nil) {
            description="Hall"
        } else if (picInfos[2].rangeOfString("STAIRSCAM") != nil) {
            description="Garden"
        } else {
            description="Cats"
        }
        self.image = UIImage(named: "nothingyet")
        self.loadImage()
    }

    func URL() -> NSURL {
        var URL=NSURL(string: self.url)
        return URL!
    }

    func loadImage() {
        if (self.downloading) {
            return
        }
        let url = self.URL()
        let request = NSMutableURLRequest(URL: url)
        let loginString = NSString(format: "%@:%@", username, password)
        let loginData: NSData = loginString.dataUsingEncoding(NSUTF8StringEncoding)!
        let base64LoginString = loginData.base64EncodedStringWithOptions(nil)

        // create the request
        request.HTTPMethod = "POST"
        request.setValue("Basic \(base64LoginString)", forHTTPHeaderField: "Authorization")
        self.downloading = true
        NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue(), completionHandler: {(response: NSURLResponse!,data: NSData!,error: NSError!) -> Void in
            if error == nil {
                if let blob = data {
                    self.image = UIImage(data: data)
                    self.downloaded = true
                }
            }
            else {
                println("Error: \(error.localizedDescription)")
            }
            self.downloading = false
        })
    }
}

MasterViewController.swift

import UIKit

let baseUrlString = "http://my.domain.net"
let username = "OoOoOoOoO"
let password = "xXxXxXxXx"

class MasterViewController: UITableViewController,NSURLConnectionDataDelegate{

    var detailViewController: DetailViewController!
    var objects = NSMutableArray()
    var loading: Bool = false;

    override func awakeFromNib() {
        super.awakeFromNib()
        if UIDevice.currentDevice().userInterfaceIdiom == .Pad {
            self.clearsSelectionOnViewWillAppear = false
            self.preferredContentSize = CGSize(width: 320.0, height: 600.0)
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        if let split = self.splitViewController {
            let controllers = split.viewControllers
            self.detailViewController = controllers[controllers.count-1].topViewController as? DetailViewController
            self.detailViewController.picInfos = self.objects;
        }
        self.refreshControl?.addTarget(self, action: "refresh:", forControlEvents: UIControlEvents.ValueChanged)
        self.loadPictureList()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    func insertNewObject(data: String) {
        var picInfo=PicInfo(data: data)
        objects.insertObject(picInfo, atIndex: picInfo.index)
        let indexPath = NSIndexPath(forRow: picInfo.index, inSection: 0)
        self.tableView.insertRowsAtIndexPaths([indexPath], withRowAnimation: .Automatic)
    }

    // MARK: - Segues

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "showDetail" {
            if let indexPath = self.tableView.indexPathForSelectedRow() {
                let object = objects[indexPath.row] as PicInfo
                println("following segue: \(indexPath.row) => \(object.index)")
                let controller = (segue.destinationViewController as UINavigationController).topViewController as DetailViewController
                controller.detailItem = object
                controller.navigationItem.leftBarButtonItem = self.splitViewController?.displayModeButtonItem()
                controller.navigationItem.leftItemsSupplementBackButton = true
            }
        }
    }

    // MARK: - Table View

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return objects.count
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell

        if let object = objects[indexPath.row] as? PicInfo {
            var todo=""
            if (object.downloading || !object.downloaded) {
                todo="(*)"
            }
            cell.textLabel!.text = "\(object.index): \(object.description)\(todo)"
            cell.detailTextLabel?.text = object.stamp
            if (!object.downloaded) {
                object.loadImage()
            }
            cell.imageView?.image = object.image
        }
        return cell
    }

    override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
        // Return false if you do not want the specified item to be editable.
        return false
    }

    // MARK: - Refresh
    func refresh(sender:AnyObject)
    {
        // Updating your data here...
        self.loadPictureList()
    }

    // MARK: Internet stuff

    func loadPictureList () {
        // set up the base64-encoded credentials
        if (self.loading) {
            return
        }
        self.loading = true
        let config = NSURLSessionConfiguration.defaultSessionConfiguration()
        let loginString = NSString(format: "%@:%@", username, password)
        let loginData: NSData = loginString.dataUsingEncoding(NSUTF8StringEncoding)!
        let base64LoginString = loginData.base64EncodedStringWithOptions(nil)
        let authString = "Basic \(base64LoginString)"
        config.HTTPAdditionalHeaders = ["Authorization" : authString]
        let session = NSURLSession(configuration: config)

        // create the request
        let url = NSURL(string: baseUrlString + "/latest.php")
        let request = NSMutableURLRequest(URL: url!)

        // fire off the request
        var task = session.dataTaskWithURL(url!){
            (data, response, error) -> Void in
            if error != nil {
                self.handlePictureList("", encounteredProblem:"\(error.localizedDescription)\nurl:\(url)")
            } else {
                var result = NSString(data: data, encoding: NSASCIIStringEncoding)!
                self.handlePictureList(result, encounteredProblem:"")
            }
        }
        task.resume()

    }

    func handlePictureList (data: NSString, encounteredProblem error: NSString) {
        if (error.length>0) {
            println ("Had error: [\(error)]")
        } else {
            println ("Got data!")
            println("Refresh will start")
            self.tableView.beginUpdates()
            for o in objects {
                let p = o as PicInfo
                var i=NSIndexPath(forRow: p.index, inSection: 0)
                self.tableView.deleteRowsAtIndexPaths([i], withRowAnimation: UITableViewRowAnimation.Fade)
                objects.removeObject(o)

            }
            var pixArr = data.componentsSeparatedByString("\n")
            for unparsedPicInfo in pixArr {
                if (unparsedPicInfo.hasPrefix("<tr>")) {
                    var picInfo=unparsedPicInfo.stringByReplacingOccurrencesOfString("<tr><td>", withString: "")
                    picInfo=picInfo.stringByReplacingOccurrencesOfString("</td></tr>", withString: "")
                    picInfo=picInfo.stringByReplacingOccurrencesOfString("</td><td>", withString: "\t")
                    self.insertNewObject(picInfo)
                }
            }
            self.loading = false
            self.tableView.endUpdates()
            self.tableView.reloadData()
            println("Refresh is over")
        }
        return
    }
}

DetailViewController.swift

import UIKit

class DetailViewController: UIViewController {

    @IBOutlet weak var detailDescriptionLabel: UILabel!
    @IBOutlet weak var pictureView: UIImageView!
    @IBOutlet weak var progressView: UIProgressView!

    var picInfos: NSMutableArray!

    var detailItem: AnyObject? {
        didSet {
            // Update the view.
            if let detail = detailItem as? PicInfo {
            println("Preparing to display object#\(detail.index)")
            } else {
                println("Bizarre?!")
            }
            self.configureView()
        }
    }

    func configureView() {
        // Update the user interface for the detail item.
        if let detail = detailItem as? PicInfo {
            if let label = self.detailDescriptionLabel {
                var todo=""
                if (detail.downloading || !detail.downloaded) {
                    todo="(*)"
                }
                label.text = "\(detail.index): \(detail.description)\(todo)"
            }
            self.title = detail.stamp
            if let proVi = self.progressView {
                if let pi = self.picInfos {
                var total = pi.count
                    if ( total==0 ) {
                        total=1
                    }
                    proVi.setProgress( Float(Double(detail.index) / Double(total)), animated: true)
                }
            }
            if let img = self.pictureView {
                if (!detail.downloaded) {
                    detail.loadImage()
                }
                img.image = detail.image
            }
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        self.configureView()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

预先感谢您的帮助.

推荐答案

我切换到CoreData以获得一些灵活性.

I switched to CoreData in order to gain some flexibility.

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