CODEWITHSUNDEEP
iosswiftuibuttonswitch-statement
SwiftyJD
SwiftyJD

Reputation: 5441

How to use != in a switch statement?

Currently we have a cell with 5 buttons, when one button is pressed it will turn white while all other buttons will turn black. There is a separate checkmark imageview on the button that will be checked or unchecked depending if the button is selected. So fat this works for the imageView:

 @IBAction func changeColor(_ sender: Any) {
        guard let button = sender as? UIButton else {
            return
        }

        self.selectedCheckMarkImageView1.isHidden = button.tag != 1
        self.selectedCheckMarkImageView2.isHidden = button.tag != 2
        self.selectedCheckMarkImageView3.isHidden = button.tag != 3
        self.selectedCheckMarkImageView4.isHidden = button.tag != 4
        self.selectedCheckMarkImageView5.isHidden = button.tag != 5
}

but when trying to use the same approach for changing button image:

 button.setImage(UIImage(named: "LR - Nano White - Selected")!, for: .normal) = button.tag != 1

an error occurs:

Cannot assign to value: function call returns immutable value

I tried putting it in a switch statement like this:

  switch (button.tag) {

        case != 1: //error occurs here


        default:
           //
        }

but get the error:

'!=' is not a prefix unary operator

Any idea on how to solve this issue?

Upvotes: 0

Views: 90

Answers (2)

Vinay Kiran
Vinay Kiran

Reputation: 347

Try this 

switch (button.tag) {

        case _ where button.tag != 1: 


        default:
           //
        }

Upvotes: 1

Alexander
Alexander

Reputation: 63167

A switch is a replacement for 1 value being compared against a fix set of multiple values other values, to pick a single branch of execution to take. You have a situation in which multiple values are checked against multiple different values, and doing multiple different things in response. A single switch can't really replace that.

Instead, I suggest reduce repetition by using a for loop.

let selectedCheckMarkImageViews = [
    selectedCheckMarkImageView1,
    selectedCheckMarkImageView2,
    selectedCheckMarkImageView3,
    selectedCheckMarkImageView4,
    selectedCheckMarkImageView5,
]

let visbleImageViewIndex = button.tag // TODO: either number these 0..<4, or add 1 below
for (index, view) in selectedCheckMarkImageViews.enumerated() {
    view.isHidden = visbleImageViewIndex != index
}

Upvotes: 2

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