Swift中的Hello World程序出现“ NSInvalidArgumentException”

Question

I'm working on a simple swift app, using the guide found at this website( http://jamesonquave.com/blog/developing-ios-apps-using-swift-part-4-adding-interactions/ ). I'm at the forth step as shown above, and my code compiles but I get an exception when I actually run the code. This is the top of the exception:

2014-12-30 16:54:52.514 HelloWorld[3058:151440] Unknown class _TtC10HelloWorld14ViewController in >Interface Builder file. Hello World! 2014-12-30 16:54:52.538 HelloWorld[3058:151440] -[UIViewController tableView:numberOfRowsInSection:]: ?>unrecognized selector sent to instance 0x7fcff07375d0 2014-12-30 16:54:52.542 HelloWorld[3058:151440] *** Terminating app due to uncaught exception >'NSInvalidArgumentException', reason: '-[UIViewController tableView:numberOfRowsInSection:]: >unrecognized selector sent to instance 0x7fcff07375d0'

I will add the code I have for a SearchResultsViewController and an APIController which contains code to make a call to the google API. I also have a table in the Main.Storyboard which is a datastore and delegate for tableData variable in SearchResultsViewController.

SearchResultsViewController.swift:

import UIKit

class SearchResultsViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, APIControllerProtocol {

    @IBOutlet var appsTableView : UITableView?
    var tableData = []
    var api = APIController()

    override func viewDidLoad() {
        super.viewDidLoad()
        api.searchItunesFor("Angry Birds")
        api.delegate = self
    }

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

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

    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell: UITableViewCell = UITableViewCell(style: UITableViewCellStyle.Subtitle, reuseIdentifier: "MyTestCell")

        let rowData: NSDictionary = self.tableData[indexPath.row] as NSDictionary

        cell.textLabel?.text = rowData["trackName"] as? String

        // Grab the artworkUrl60 key to get an image URL for the app's thumbnail
        let urlString: NSString = rowData["artworkUrl60"] as NSString
        let imgURL: NSURL? = NSURL(string: urlString)

        // Download an NSData representation of the image at the URL
        let imgData = NSData(contentsOfURL: imgURL!)
        cell.imageView?.image = UIImage(data: imgData)

        // Get the formatted price string for display in the subtitle
        let formattedPrice: NSString = rowData["formattedPrice"] as NSString

        cell.detailTextLabel?.text = formattedPrice

        return cell
    }

    func didReceiveAPIResults(results: NSDictionary) {
        var resultsArr: NSArray = results["results"] as NSArray
        dispatch_async(dispatch_get_main_queue(), {
            self.tableData = resultsArr
            self.appsTableView!.reloadData()
        })
    }

}

APIController.swift: import Foundation

protocol APIControllerProtocol {
    func didReceiveAPIResults(results: NSDictionary)
}

class APIController {

    var delegate: APIControllerProtocol?

    init() {
    }

    func searchItunesFor(searchTerm: String) {

        // The iTunes API wants multiple terms separated by + symbols, so replace spaces with + signs
        let itunesSearchTerm = searchTerm.stringByReplacingOccurrencesOfString(" ", withString: "+", options: NSStringCompareOptions.CaseInsensitiveSearch, range: nil)

        // Now escape anything else that isn't URL-friendly
        if let escapedSearchTerm = itunesSearchTerm.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding) {
            let urlPath = "http://itunes.apple.com/search?term=\(escapedSearchTerm)&media=software"
            let url = NSURL(string: urlPath)
            let session = NSURLSession.sharedSession()
            let task = session.dataTaskWithURL(url, completionHandler: {data, response, error -> Void in
                println("Task completed")
                if(error != nil) {
                    // If there is an error in the web request, print it to the console
                    println(error.localizedDescription)
                }
                var err: NSError?

                var jsonResult = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &err) as NSDictionary
                if(err != nil) {
                    // If there is an error parsing JSON, print it to the console
                    println("JSON Error \(err!.localizedDescription)")
                }
                let results: NSArray = jsonResult["results"] as NSArray
                self.delegate?.didReceiveAPIResults(jsonResult)
            })

            task.resume()
        }
    }

}

Any suggestions or help would be appreciated, I've spent a couple hours trying to solve this and searching for an answer but to no avail. I think the problem lies some where in the fact that I renamed SearchResultsViewController and that the variable tableData isn't properly linked anymore but I have no evidence that is correct. Thank you again.

Answer 1

Unknown class _TtC10HelloWorld14ViewController in >Interface Builder file

There's your answer. The problem is that you changed the name of the ViewController class, to SearchResultsViewController - but you didn't tell the storyboard about that. You need to tell it. Find that scene and tell it the correct view controller class name in the Identity inspector.

I think the problem lies some where in the fact that I renamed SearchResultsViewController

Yes, I see now that you already know this. So just fix it.