Swift: Why is this immutable? - swift

Question

Can you tell me why this code does not work?
I have several arrays of [AnyObject] that contain UILabels and UITextForm.
This func should take as parameter an array and make all the labels and the text form disabled. I've tried with map, but still i have the same problem, the compiler tells me that or the variable is a constant or that is immutable.
func disableSectionForm(formSection section: inout [AnyObject]) {
for i in 0...section.count {
if section[i] is UILabel || section[i] is UITextField {
section[i].isEnabled = false
}
}
}

Answer 1

There are many compile errors here
Issue #1 (this is just a suggestion)
inout is not needed here because you are not mutating the section array, you are mutating the objects inside it instead.
Issue #2
The inout should go before the param name (if you are using Swift 2.2)
Issue #3
You should use self when comparing with dynamicType
Issue #4
You can't write section[i].isEnabled = false because AnyObject has no member isEnabled so you should do a cast
Issue #5
You are accessing an index outside of your array so this
0...section.count
should become this
0..<section.count
Code Version #1
Now your code looks like this
func disableSectionForm(formSection section: [AnyObject]) {
for i in 0..<section.count {
if section[i].dynamicType == UILabel.self {
(section[i] as? UILabel)?.enabled = false
} else if section[i].dynamicType == UITextField.self {
(section[i] as? UITextField)?.enabled = false
}
}
}
Code Version #2
Since:
you can iterate your elements in a safer way
you should use conditional cast instead of dynamicType comparation
you can write in
Swift 2.2
func disableSectionForm(formSection section: [AnyObject]) {
section.forEach {
switch $0 {
case let label as UILabel: label.enabled = false
case let textField as UITextField: textField.enabled = false
default: break
}
}
}
Swift 3.0 (beta 6)
func disableSectionForm(formSection section: [Any]) {
section.forEach {
switch $0 {
case let label as UILabel: label.isEnabled = false
case let textField as UITextField: textField.isEnabled = false
default: break
}
}
}
Code Version #3
Let's define a protocol to represents classes with an enabled Bool property.
Swift 2.2
protocol HasEnabledProperty:class {
var enabled: Bool { get set }
}
Let's conform to it UILabel and UITextLabel
extension UILabel: HasEnabledProperty { }
extension UITextField: HasEnabledProperty { }
And finally...
func disableSectionForm(formSection section: [AnyObject]) {
section.flatMap { $0 as? HasEnabledProperty }.forEach { $0.enabled = false }
}
Swift 3.0 (beta 6)
protocol HasEnabledProperty:class {
var isEnabled: Bool { get set }
}
extension UILabel: HasEnabledProperty { }
extension UITextField: HasEnabledProperty { }
func disableSectionForm(formSection section: [Any]) {
section.flatMap { $0 as? HasEnabledProperty }.forEach { $0.isEnabled = false }
}

Answer 2

try to check if let block and use optionals
func disableSectionForm(formSection section: inout [AnyObject]) {
for i in 0...section.count {
if let label = section[i] as? UILabel {
label.isEnabled = false
}
if let textField = section[i] as? UITextFiled {
textField.isEnabled = false
}
}
}