App crash when reload button is pressed

Question

i'm having some problems with my weather app for iOS. I'm new in programming in xCode, so it could be a silly error. Anyway, the problem is: I'm trying to add a refresh button in my Single Page App. The button has a IBAction function associated, so that when it is pressed it should get hidden and the activity indicator should appear. That is the function:

@IBAction func reload() {

    refreshButton.hidden = true
    refreshActivityIndicator.hidden = false
    refreshActivityIndicator.startAnimating()

}

and that is the declaration of the variables:

 @IBOutlet weak var refreshButton: UIButton! 

@IBOutlet weak var refreshActivityIndicator: UIActivityIndicatorView!

when i run the app and press the refresh button, the app crash and i get this error:

@UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate { <--thread 1 signal sigarbt

the console doesn't show anything else. What could be the problem?

// APPDELEGATE.SWIFT

import UIKit

@UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?


func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    // Override point for customization after application launch.

    application.setStatusBarHidden(true, withAnimation: .None)

    return true
}

func applicationWillResignActive(application: UIApplication) {
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}

func applicationDidEnterBackground(application: UIApplication) {
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}

func applicationWillEnterForeground(application: UIApplication) {
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
}

func applicationDidBecomeActive(application: UIApplication) {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}

func applicationWillTerminate(application: UIApplication) {
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}

}

//VIEWCONTROLLER.SWIFT import UIKit import Foundation

class ViewController: UIViewController {

private let apiKey = "447073dc853014a6fa37376c43d8462b"

@IBOutlet weak var iconView: UIImageView!
@IBOutlet weak var currentTimeLabel: UILabel!
@IBOutlet weak var temperatureLabel: UILabel!
@IBOutlet weak var humidityLabel: UILabel!
@IBOutlet weak var precipitationLabel: UILabel!
@IBOutlet weak var summaryLabel: UILabel!

@IBOutlet weak var refreshButton: UIButton!

@IBOutlet weak var refreshActivityIndicator: UIActivityIndicatorView!


override func viewDidLoad() {

    super.viewDidLoad()

    // Do any additional setup after loading the view, typically from a nib.

    refreshActivityIndicator.hidden = true

    // base URL

    let baseURL = NSURL(string: "https://api.forecast.io/forecast/\(apiKey)/")

    // add coordinates to base url (API syntax)

    let forecastURL = NSURL(string: "44.698150,10.656846", relativeToURL: baseURL)

    // NSURL SESSION 
    //The NSURLSession class and related classes provide an API for downloading content via HTTP. This API provides a rich set of delegate methods for supporting authentication and gives your app the ability to perform background downloads when your app is not running or, in iOS, while your app is suspended. With the NSURLSession API, your app creates a series of sessions, each of which coordinates a group of related data transfer tasks. For example, if you are writing a web browser, your app might create one session per tab or window. Within each session, your app adds a series of tasks, each of which represents a request for a specific URL (and for any follow-on URLs if the original URL returned an HTTP redirect).

    let sharedSession = NSURLSession.sharedSession()



    let downloadTask : NSURLSessionDownloadTask = sharedSession.downloadTaskWithURL(forecastURL!, completionHandler:

        { (location: NSURL!, response: NSURLResponse!, error: NSError!) -> Void in

        if (error == nil) {

            let dataObject = NSData(contentsOfURL: location) // convert in NSData object

            // serialize NSData object in Json as Dictionary

            let weatherDictionary: NSDictionary = NSJSONSerialization.JSONObjectWithData(dataObject!, options: nil, error: nil) as NSDictionary

            // instance of Current (Current.swift) init with weatherDictionary

            let currentWeather = Current(weatherDictionary: weatherDictionary)


            // we put the code in the main queue cause this is relative the UI, that have the first thread (concurrency)

            dispatch_async(dispatch_get_main_queue(), { () -> Void in

                self.temperatureLabel.text = "\(currentWeather.temperature)"
                self.iconView.image = currentWeather.icon!
                self.currentTimeLabel.text = "At \(currentWeather.currentTime!) it is"
                self.humidityLabel.text = "\(currentWeather.humidity)"
                self.precipitationLabel.text = "\(currentWeather.precipProbability)"
                self.summaryLabel.text = "\(currentWeather.summary)"

                // Stop refresh animation

                self.refreshActivityIndicator.stopAnimating()
                self.refreshActivityIndicator.hidden = true
                self.refreshButton.hidden = false

            })

        }


    })

    downloadTask.resume() // call sharedSession.downloadTaskWithURL -> store json data in location (local temporary memory)


}


@IBAction func reload() {
    println("PRESSED")
}

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

}

I haven't got any .h or .m file.

Answer 1

Is reload function even getting called? If you are using storyboard/Xib for creating the UIButton then link the reload function in Xib on touchUpInside Event or if you are creating the UIButton event in code then like below:

Create another UIButton property in .h file: @property(nonatomic, strong) UIButton *refresh;

In .m file

-(void) viewDidLoad {
self.refresh = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[self.refresh addTarget:self 
       action:@selector(reload:) forControlEvents:UIControlEventTouchUpInside];
[self.refresh setTitle:@"Reload" forState:UIControlStateNormal];
self.refresh .frame = CGRectMake(80.0, 210.0, 160.0, 40.0);
[self.view addSubview:self.refresh];
}


-(void) reload:(UIButton*)sender
{
    NSLog(@"you clicked on button %@", sender.tag);
    if(self.refresh.hidden) {
        self.refresh.hidden = false;
    } else {
        self.refresh.hidden = true;
    }
}

Answer 2

Okay it works! Please don't ask me why :) I simply deleted the code and rewrote it. And it works. Call it magic. Thank you all for your answers.