How to solve Fatal error: Index out of range in Swift IOS

问题

I have a problem with a code is a RSS reader app for IOS. I have an error Thread 1: Fatal error: Index out of range.

I wrote on which line the error is. By the way, this error does happen with all the RSS link I put for example with sky news RSS URL it works well but with some site (like the one I put now) it is not running and write Fatal error: Index out of range ERROR.

The Code:

import UIKit

class FeedListViewController: UITableViewController, XMLParserDelegate {

    var myFeed : NSArray = []
    var feedImgs: [AnyObject] = []
    var url: URL!

    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.rowHeight = UITableViewAutomaticDimension
        tableView.estimatedRowHeight = 140
        tableView.backgroundColor = UIColorFromRGB(rgbValue: 0x00B6ED)
        self.tableView.dataSource = self
        self.tableView.delegate = self

        loadData()
    }

    @IBAction func refreshFeed(_ sender: Any) {

        loadData()
    }

    func loadData() {
        url = URL(string: "https://www.widgeti.co.il/feed")!
        loadRss(url);
    }

    func loadRss(_ data: URL) {
        // XmlParserManager instance/object/variable
        let myParser : XmlParserManager = XmlParserManager().initWithURL(data) as! XmlParserManager
        // Put feed in array
        feedImgs = myParser.img as [AnyObject]
        myFeed = myParser.feeds
        tableView.reloadData()
    }

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

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "openPage" {
            let indexPath: IndexPath = self.tableView.indexPathForSelectedRow!
            let selectedFURL: String = (myFeed[indexPath.row] as AnyObject).object(forKey: "link") as! String
            // Instance of our feedpageviewcontrolelr
            let fivc: FeedItemViewController = segue.destination as! FeedItemViewController
            fivc.selectedFeedURL = selectedFURL as String
        }
    }

    // MARK: - Table view data source
    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

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

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
        cell.textLabel?.backgroundColor = UIColor.clear
        cell.detailTextLabel?.backgroundColor = UIColor.clear

        if indexPath.row % 2 == 0 {
            cell.backgroundColor = UIColor(white: 1, alpha: 0.1)
        } else {
            cell.backgroundColor = UIColor(white: 1, alpha: 0.2)
        }

        // Load feed iamge.



        let url = NSURL(string:feedImgs[indexPath.row] as! String) //ERROR Thread 1: Fatal error: Index out of range
        let data = NSData(contentsOf:url! as URL)
        var image = UIImage(data:data! as Data)
        image = resizeImage(image: image!, toTheSize: CGSize(width: 80, height: 80))
        let cellImageLayer: CALayer?  = cell.imageView?.layer
        cellImageLayer!.cornerRadius = 35
        cellImageLayer!.masksToBounds = true
        cell.imageView?.image = image
        cell.textLabel?.text = (myFeed.object(at: indexPath.row) as AnyObject).object(forKey: "title") as? String
        cell.textLabel?.textColor = UIColor.white
        cell.textLabel?.numberOfLines = 0
        cell.textLabel?.lineBreakMode = .byWordWrapping

        cell.detailTextLabel?.text = (myFeed.object(at: indexPath.row) as AnyObject).object(forKey: "pubDate") as? String
        cell.detailTextLabel?.textColor = UIColor.white

        return cell
    }

    func UIColorFromRGB(rgbValue: UInt) -> UIColor {
        return UIColor(
            red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
            green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
            blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
            alpha: CGFloat(1.0)
        )
    }

    func resizeImage(image:UIImage, toTheSize size:CGSize)->UIImage{


        let scale = CGFloat(max(size.width/image.size.width,
                                size.height/image.size.height))
        let width:CGFloat  = image.size.width * scale
        let height:CGFloat = image.size.height * scale;

        let rr:CGRect = CGRect(x: 0, y: 0, width: width, height: height)

        UIGraphicsBeginImageContextWithOptions(size, false, 0);
        image.draw(in: rr)
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext();
        return newImage!
    }
}

Can You help me solve this problem? Thanks!

回答1:

Fatal error: Index out of range

This error only refers a thing that index, you want to access from the array does not exist.

let url = NSURL(string: feedImgs[indexPath.row] as! String)

In the above line feedImgs[indexPath.row] does not exist, that why you are getting the error. Make sure that your feedImgs array and myFeed array both are of same length because you are loading the table from myFeed array.

Or, You can can check like this.

if feedImgs.count > indexPath.row {
    let url = NSURL(string: (feedImgs[indexPath.row] ?? ""))
}

来源：https://stackoverflow.com/questions/50449750/how-to-solve-fatal-error-index-out-of-range-in-swift-ios