Swift: Thread 1 signal SIGABRT in class AppDelegate: UIResponder, UIApplicationDelegate

Question

I'm following a tutorial and every time I click the button I get an error in AppDelegate.swift that says Thread 1 signal SIGABRT.

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate { //Thread 1 signal SIGABRT

Here's a screenshot of my storyboard.

I have looked all over and some answers refer to an IBOutlet connection that doesn't exist but as you can see in the screenshot all my connections look good so I don't know what the problem is.

here's my viewController.swift code: import UIKit

class ViewController: UIViewController {

@IBOutlet weak var input: UITextField!
@IBOutlet weak var label: UILabel!

@IBAction func button(_ sender: UIButton) {
    label.text = input.text
    UserDefaults.standard.set(input, forKey: "myName")
    input.text = " "
}

override func viewDidLoad() {
    super.viewDidLoad()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

override func viewDidAppear(_ animated: Bool) {
    if let x = UserDefaults.standard.object(forKey: "myName") as? String{
      label.text = x
    }
}

}

here's the complete error message that I get when I click the button: 2017-08-20 23:29:09.155350+0800 asd[2297:997880] [LayoutConstraints] Unable to simultaneously satisfy constraints. Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. ( "<_UILayoutSupportConstraint:0x608000284d30 _UILayoutGuide:0x7fc28340be50.height == 20 (active)>", "<_UILayoutSupportConstraint:0x608000283980 V:|-(0)-[_UILayoutGuide:0x7fc28340be50] (active, names: '|':UIView:0x7fc28340b780 )>", "<_UILayoutSupportConstraint:0x608000284dd0 _UILayoutGuide:0x7fc28340c420.height == 0 (active)>", "<_UILayoutSupportConstraint:0x608000284d80 _UILayoutGuide:0x7fc28340c420.bottom == UIView:0x7fc28340b780.bottom (active)>", "", "", "", "", "", "", "", "" )

Will attempt to recover by breaking constraint

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger. The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in may also be helpful. 2017-08-20 23:29:11.137163+0800 asd[2297:997880] [MC] System group container for systemgroup.com.apple.configurationprofiles path is /Users/Myeongjeon/Library/Developer/CoreSimulator/Devices/200D40A8-EFD4-4FE9-8E13-37C2E7D86BA6/data/Containers/Shared/SystemGroup/systemgroup.com.apple.configurationprofiles 2017-08-20 23:29:11.137610+0800 asd[2297:997880] [MC] Reading from private effective user settings. 2017-08-20 23:29:15.719443+0800 asd[2297:997880] [User Defaults] Attempt to set a non-property-list object ; layer = > as an NSUserDefaults/CFPreferences value for key myName 2017-08-20 23:29:15.723 asd[2297:997880] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Attempt to insert non-property list object ; layer = > for key myName' * First throw call stack: ( 0 CoreFoundation 0x0000000103725b0b exceptionPreprocess + 171 1 libobjc.A.dylib 0x000000010318a141 objc_exception_throw + 48 2 CoreFoundation 0x000000010378e625 +[NSException raise:format:] + 197 3 CoreFoundation 0x0000000103678729 _CFPrefsValidateValueForKey + 249 4 CoreFoundation 0x00000001036e5afc -[CFPrefsPlistSource sendMessageSettingValue:forKey:] + 572 5 CoreFoundation 0x000000010378fdaa -[CFPrefsPlistSource alreadylocked_setValues:forKeys:count:] + 794 6 CoreFoundation 0x000000010374cc58 -[CFPrefsSource setValues:forKeys:count:removeValuesForKeys:count:] + 264 7 CoreFoundation 0x0000000103678620 -[CFPrefsSource setValues:forKeys:count:] + 32 8 CoreFoundation 0x0000000103786af6 -[CFPrefsSearchListSource alreadylocked_setValues:forKeys:count:] + 454 9 CoreFoundation 0x000000010374cc58 -[CFPrefsSource setValues:forKeys:count:removeValuesForKeys:count:] + 264 10 CoreFoundation 0x0000000103678620 -[CFPrefsSource setValues:forKeys:count:] + 32 11 CoreFoundation 0x00000001036bbfe9 -[CFPrefsSource setValue:forKey:] + 57 12 CoreFoundation 0x0000000103788a4f __108-[_CFXPreferences(SearchListAdditions) withSearchListForIdentifier:container:cloudConfigurationURL:perform:]_block_invoke + 319 13 CoreFoundation 0x000000010378824d normalizeQuintuplet + 317 14 CoreFoundation 0x0000000103788909 -[_CFXPreferences(SearchListAdditions) withSearchListForIdentifier:container:cloudConfigurationURL:perform:] + 105 15 CoreFoundation 0x0000000103772c15 -[_CFXPreferences setValue:forKey:appIdentifier:container:configurationURL:] + 261 16 CoreFoundation 0x00000001036bbf34 _CFPreferencesSetAppValueWithContainer + 68 17 Foundation 0x0000000102c89790 -[NSUserDefaults(NSUserDefaults) setObject:forKey:] + 55 18 asd 0x0000000102bafc51 TFC3asd14ViewController6buttonfCSo8UIButtonT + 1073 19 asd 0x0000000102baff6a TToFC3asd14ViewController6buttonfCSo8UIButtonT + 58 20 UIKit 0x0000000103b4ad82 -[UIApplication sendAction:to:from:forEvent:] + 83 21 UIKit 0x0000000103ccf5ac -[UIControl sendAction:to:forEvent:] + 67 22 UIKit 0x0000000103ccf8c7 -[UIControl _sendActionsForEvents:withEvent:] + 450 23 UIKit 0x0000000103cce802 -[UIControl touchesEnded:withEvent:] + 618 24 UIKit 0x0000000103bb87ea -[UIWindow _sendTouchesForEvent:] + 2707 25 UIKit 0x0000000103bb9f00 -[UIWindow sendEvent:] + 4114 26 UIKit 0x0000000103b66a84 -[UIApplication sendEvent:] + 352 27 UIKit 0x000000010434a5d4 __dispatchPreprocessedEventFromEventQueue + 2926 28 UIKit 0x0000000104342532 __handleEventQueue + 1122 29 CoreFoundation 0x00000001036cbc01 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION + 17 30 CoreFoundation 0x00000001036b10cf __CFRunLoopDoSources0 + 527 31 CoreFoundation 0x00000001036b05ff __CFRunLoopRun + 911 32 CoreFoundation 0x00000001036b0016 CFRunLoopRunSpecific + 406 33 GraphicsServices 0x0000000107d05a24 GSEventRunModal + 62 34 UIKit 0x0000000103b49134 UIApplicationMain + 159 35 asd 0x0000000102bb1927 main + 55 36 libdyld.dylib 0x0000000106d9a65d start + 1 ) libc++abi.dylib: terminating with uncaught exception of type NSException

Answer 1

What's critically wrong with your code is here:

@IBOutlet weak var input: UITextField!

@IBAction func button(_ sender: UIButton) {
    label.text = input.text
    UserDefaults.standard.set(input, forKey: "myName")
    input.text = " "
}

You are trying to save input into the standard UserDefaults, but input is a UITextField. You cannot save UITextField into UserDefaults.

Maybe you want to do something like this:

@IBAction func button(_ sender: UIButton) {
    label.text = input.text
    UserDefaults.standard.set(input.text ?? "", forKey: "myName")
    input.text = " "
}

The most important part in your debug output:

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Attempt to insert non-property list object ; layer = > for key myName'

It is saying that your code is trying to set an invalid value for the key myName.

Messages about constraints suggests your code and storyboard settings may need to be fixed, but it is not the cause of the crash.