Class has no initializers: Swift Error

Question

I have a problem with my ViewController.

My code has an error about initializers and I can't understand why.

Please, take a moment to look at my code:

import UIKit

class ViewController: UIViewController, UITableViewDataSource {

let sectionsTableIdentifier = "SectionsTableIdentifier"

var names: [String: [String]]!
var keys: [String]!

@IBOutlet weak var tableView: UITableView!

var searchController: UISearchController

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

    tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: sectionsTableIdentifier)

    let path = NSBundle.mainBundle().pathForResource("sortednames", ofType: "plist")

    let namesDict = NSDictionary(contentsOfFile: path!)
    names = namesDict as! [String: [String]]
    keys = namesDict!.allKeys as! [String]
    keys = keys.sort()

    let resultsController = SearchResultsController()

    resultsController.names = names
    resultsController.keys = keys
    searchController = UISearchController(searchResultsController: resultsController)

    let searchBar = searchController.searchBar
    searchBar.scopeButtonTitles = ["All", "Short", "Long"]
    searchBar.placeholder = "Enter a search term"

    searchBar.sizeToFit()
    tableView.tableHeaderView = searchBar
    searchController.searchResultsUpdater = resultsController

}

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


func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    return keys.count
}

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    let key = keys[section]
    let nameSection = names[key]!
    return nameSection.count
}

func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
    return keys[section]
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier(sectionsTableIdentifier, forIndexPath: indexPath) as UITableViewCell

    let key = keys[indexPath.section]
    let nameSection = names[key]!
    cell.textLabel!.text = nameSection[indexPath.row]

    return cell
}

func sectionIndexTitlesForTableView(tableView: UITableView) -> [String]? {


       return keys
    }

}

What is the problem? The error is that the class has no initializer. I have no variables with no value.

Solution 1

Problematic line is

var searchController: UISearchController

Change it to

var searchController: UISearchController!

or if you are not initializing it in view life cycles, use optional to avoid crashes:

var searchController: UISearchController?

Solution 2

Your line which catch the error is:

var searchController: UISearchController

because you never init searchController in a LifeCycle init function from your UIViewController. I advice you not to force unwrap the var (like Sahil said above) but to properly init it into an init func like this:

override init(frame: CGRect) {
    super.init(frame: frame)

    setUp()
}

required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)

    setUp()
}

func setUp() {
    searchController = UISearchController() //Or any init you can use to perform some custom initialization
}

In Swift, you always should avoid force unwrap Object like above, to avoid crash in your app, or use if-Let/Guard-Let template

Cheers from France

Comments

[Korpel]

perhaps it would be better to be "var searchController: UISearchController?" instead so if it is nil there won't crash the application. plus it will get the default initialiser of nil

[Sahil Kapoor]

Yeah, added that to answer. Thanks :)