How to disable a button when the 1st row in a custom picker view is selected?

Question

I have a custom UIPickerView class (also conforms to UIPickerViewDelegate, UIPickerViewDataSource) that is used in 2 view controllers. So in both of them I have this: myPickerView.delegate = myPickerView and same with dataSource. All the rows and components are configured in that custom picker view class.

I want to disable a button in my VCs when the 1st row is selected. Usually I would do this by using one of the picker view's delegate functions (pickerView(_:,didSelectRow:, inComponent:), but since I use a custom one that already conforms to UIPickerViewDelegate, I can't do that.

Answer 1

Hmm, tricky. The issue is that the picker is its own delegate, which makes the solution a bit complicated, but here's what I might do: give the picker a closure that gets called when the selected row changes. Then call that closure from the delegate method.

class MyPickerView {
    typealias SelectedIndexClosure = (Int) -> Void
    var selectedIndexClosure: SelectedIndexClosure = { _ in }

...

    func picker(_ picker: UIPickerView, didSelectRow row: Int ...) {
        selectedIndexClosure(row)
    }
}

Then you'd set the selectedIndexClosure to whatever code you want to be run in the view controller.

myPickerView.selectedIndexClosure = { [weak self] index in
    self?.button.enabled = (index == 1)
}

And that should do. An more idiomatic solution might be to refactor the picker's datasource and delegate methods into a new, separate object owned by the view controller, but this should work fine.