Access to value of the variable in if statement - swift

Question

I need to access the value of a variable in a if statement, this is my code:
var codeError : Int?
#IBAction func mySwitch(_ sender: UISwitch) {
if sender.isOn {
codeError = 1
} else {
codeError = 2
}
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if codeError == 1 {
front()
} else if codeError == 2 {
back()
}
}
My two functions, this is my front() function:
func front() {
let deviceDiscoverySession = AVCaptureDeviceDiscoverySession(deviceTypes: [AVCaptureDeviceType.builtInDualCamera, AVCaptureDeviceType.builtInTelephotoCamera,AVCaptureDeviceType.builtInWideAngleCamera], mediaType: AVMediaTypeVideo, position: AVCaptureDevicePosition.unspecified)
for device in (deviceDiscoverySession?.devices)! {
if device.position == AVCaptureDevicePosition.front {
do {
let input = try AVCaptureDeviceInput(device: device)
if captureSession.canAddInput(input) {
captureSession.addInput(input)
if captureSession.canAddOutput(photoOutput) {
captureSession.addOutput(photoOutput)
previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
previewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
previewLayer?.connection.videoOrientation = AVCaptureVideoOrientation.portrait
cameraView.layer.addSublayer(previewLayer!)
}
}
} catch {
print("Error")
}
}
}
captureSession.startRunning()
print("😇")
}
And back() function:
func back() {
let deviceDiscoverySession = AVCaptureDeviceDiscoverySession(deviceTypes: [AVCaptureDeviceType.builtInDualCamera, AVCaptureDeviceType.builtInTelephotoCamera,AVCaptureDeviceType.builtInWideAngleCamera], mediaType: AVMediaTypeVideo, position: AVCaptureDevicePosition.unspecified)
for device in (deviceDiscoverySession?.devices)! {
if device.position == AVCaptureDevicePosition.back {
do {
let input = try AVCaptureDeviceInput(device: device)
if cS.canAddInput(input) {
cS.addInput(input)
if cS.canAddOutput(photoOutput) {
cS.addOutput(photoOutput)
previewLayer = AVCaptureVideoPreviewLayer(session: cS)
previewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
previewLayer?.connection.videoOrientation = AVCaptureVideoOrientation.portrait
cameraView.layer.addSublayer(previewLayer!)
}
}
} catch {
print("Error")
}
}
}
cS.startRunning()
print("🙃")
}
The problem is when I run the app. I get a nil value of the codeError when I should get 1 o 2.
How do I solve this?

Answer 1

I'm not sure why you're accessing a variable set by user when interacting with the view on viewWillAppear. I suggest spending some time and studying UIViewController life cycles.
But if you just want to print error codes on switch changing values, this should do it.
var codeError : Int?
#IBAction func mySwitch(_ sender: UISwitch) {
if sender.isOn {
codeError = 1
} else {
codeError = 2
}
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
// will print nothing since errorCode is not set
printCodeError()
}
func printCodeError() {
if let codeError = self.codeError {
print("\(codeError)")
}
}

Answer 2

it is working like you original code. but you print it inside viewWillAppear. but at this time it is not initialized from you uiswitch.
one solution: give it default value:
var codeError: Int = 1
or shorter
var codeError = 1
Note:
viewWillAppear(_:)
Notifies the view controller that its view is about to be added to a view hierarchy.
see https://developer.apple.com/reference/uikit/uiviewcontroller/1621510-viewwillappear
but it is called on the view where your UISwitch is on. for your main goal (hidden in comments on the other answer) it is the wrong place to print out the variable