Swift 3中的背景颜色更改

Question

import UIKit

class ViewController: UIViewController {

    @IBAction func CyanBackground(sender: AnyObject) {
        view.backgroundColor = UIColor.cyan
    }

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

I am simply trying to change the background color in Swift, but when I try to click the button I made, Xcode goes to a different page and highlights this line:

class AppDelegate: UIResponder, UIApplicationDelegate {

This shows up in the console:

( 0 CoreFoundation 0x000000010915a34b exceptionPreprocess + 171 1 libobjc.A.dylib 0x000000010660121e objc_exception_throw + 48 2 CoreFoundation 0x00000001091c9f34 -[NSObject(NSObject) doesNotRecognizeSelector:] + 132 3 CoreFoundation 0x00000001090dfc15 __forwarding + 1013 4 CoreFoundation 0x00000001090df798 _CF_forwarding_prep_0 + 120 5 UIKit 0x0000000106ad26c8 -[UIApplication sendAction:to:from:forEvent:] + 83 6

Any experienced Swift developers who can help me out?

Thanks, Fareed

Answer 1

The problem is with an outlet. Maybe you deleted the line of code and/or replaced it, but the link still exists.

In your main.storyboard check all the outlets, control+(click on outlet) and check if it is linked to something. Once you correct that it should run with no problems.

Answer 2

Try this...you have problem with your IBOutlet...

   @IBAction func Background Cyan(sender: UIButton) {
   view.backgroundColor = UIColor.cyan  
   }

Paste this code into yourstoryboard and reconnect the outlet. This will do the job...