Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArray0 objectAtIndex:]: index 0 beyond bounds for empty NSArray'

Question

I am fetching the labels, text and image through API. When API has data , it shows without error. But when the API is nil, it throws error as:

Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArray0 objectAtIndex:]: index 0 beyond bounds for empty NSArray'.

I need it to show null if API provides nil value but prevent from crash. Anyone out there please help to solve this issue in Swift 3. The code is given below:

import UIKit
import Alamofire

class Instructors: UIViewController {

    @IBOutlet var fullName: UILabel!
    @IBOutlet var post: UILabel!
    @IBOutlet var descriptionName: UITextView!
    @IBOutlet var instructorImage: UIImageView!

    var dictDataContent:NSDictionary = NSDictionary()
    var dictData:NSArray = NSArray()
    var dictprofile:NSDictionary = NSDictionary()

    override func viewDidLoad() {
        super.viewDidLoad()
        self.dictData = (dictDataContent.value(forKey: "instructors") as AnyObject) as! NSArray
        self.dictprofile = (dictData.object(at: 0) as AnyObject) as! NSDictionary
        let url:URL = URL(string: (self.dictprofile.value(forKey: "profile_image")) as! String)!
        SDWebImageManager.shared().downloadImage(with: url, options: [],progress: nil, completed: {[weak self] (image, error, cached, finished, url) in
            if self != nil {
              self?.instructorImage.image = image
            }
        })

        self.fullName.text = dictprofile.value(forKey: "full_name") as! String?
        self.post.text = dictprofile.value(forKey: "designation") as! String?
        self.descriptionName.text = dictprofile.value(forKey: "description") as! String?
    }

}

Answer 1

So what I understand from your problem is your API might have data and sometimes no data. This is the behavior of Optionals in swift. So you need to have optional variables for storing your data.

Changing your NSDictionary and NSArray variables to optional might help. Try the code below:

class Instructors: UIViewController {
    @IBOutlet var fullName: UILabel!
    @IBOutlet var post: UILabel!
    @IBOutlet var descriptionName: UITextView!
    @IBOutlet var instructorImage: UIImageView!

    var dictDataContent:NSDictionary?
    var dictData:NSArray?
    var dictprofile:NSDictionary?
    override func viewDidLoad() {
        super.viewDidLoad()
        dictData = dictDataContent?.value(forKey: "instructors") as? NSArray
        if let count = dictData?.count, count > 0 {
            dictprofile = dictData?.object(at: 0) as? NSDictionary
        }
        if let urlString = dictprofile?.value(forKey: "profile_image") as? String {
            if let url = URL(string: urlString) {
                SDWebImageManager.shared().downloadImage(with: url, options: [],progress: nil, completed: {[weak self] (image, error, cached, finished, url) in
                    if self != nil {
                        self?.instructorImage.image = image
                    }
                })
            }
        }
        fullName.text = dictprofile?.value(forKey: "full_name") as? String
        post.text = dictprofile?.value(forKey: "designation") as? String
        descriptionName.text = dictprofile?.value(forKey: "description") as? String
    }
}