Get an outlet variable by name

Question

Looking for a way to access an outlet programmatically in swift:

@IBOutlet var label1: UILabel?
var outletName = "label1"
view[outletName].text = "hello, world!"

Is the only way to do this to create my own custom mapping, like so?

@IBOutlet var label1: UILabel?
let outlets = ["label1": label1]
let outletName = "label1"
outlets[outletName].text = "hello, world!"

EDIT: Seems my original question was poorly worded, lets try again:
I'm looking to access a variable through some string identifier. In my original question I was trying to ask if a variable can be accessed by the name of the variable itself somehow. IE accessing variable label1 with a string of the variable's name "label1".

Your question is vague about what your true problem is. Do you simply have a need to have a collection of `IBOutlet`s? Or are you have trouble actually using the `IBOutlet`? I say this because outlets **ARE** programmatic. — allenh, Jul 09 '17 at 14:18
Yea I've slightly rephrased the question and edited it to better describe the goal I'm trying to achieve. I'm looking for an identifier that I can use to programatically access a variable (in this case an IBOutlet). — Rawr, Jul 09 '17 at 14:32

allenh · Accepted Answer · 2018-08-07T15:00:07.460

4

Turning a string into a property access is actually kind of difficult in pure Swift.

You can use some objective-c APIs to help you out.

// Mark your outlet variable as dynamic
@IBOutlet dynamic var label1: UILabel?

var outletName = "label1"
// Then you can access it via a key path (aka string)
if let myProperty = value(forKey: outletName) as? UILabel {
    myProperty.text = "Hello, world!"
}

edited Aug 07 '18 at 15:00

answered Jul 09 '17 at 14:34

allenh

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Thanks, this is exactly what I was trying to accomplish. – Rawr Jul 09 '17 at 14:42

score 2 · Answer 2 · edited Apr 08 '20 at 08:11

2

Swift 5 version:

if let aLabel = value(forKey: "label1") as? UILabel {
    aLabel.text = "Hello World"
}

edited Apr 08 '20 at 08:11

סטנלי גרונן

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answered Apr 08 '20 at 07:32

Türker Güney

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score 1 · Answer 3 · answered Jul 09 '17 at 14:13

1

There is a easier way to achieve your goal. First in your viewDidLoad, give yout outlet a unique tag number, other than 0

label1.tag = 1

Then, whenever you want to access it

if let theLabel = self.view.viewWithTag(1) as? UILabel {
    theLabel.text = "hello, world!"
}

answered Jul 09 '17 at 14:13

Fangming

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Tags are a very fragile way of identifying elements in a view hierarchy. They should be avoided. – allenh Jul 09 '17 at 14:16
This is the kind of solution I was looking for, is there an alternative that is less fragile? Looking for some kind of identifier to access an IBOutlet. In my original question I was hoping to access the variable by the name of the variable itself, but a tag like this answer would have been a viable alternative. – Rawr Jul 09 '17 at 14:30
@Rawr I think this is the only way that match your requirments. Yes using tag is not good but if you know what you are doing and you have **only one** tag system in your view controller, I see no harm of using it :) – Fangming Jul 09 '17 at 14:35

Get an outlet variable by name

3 Answers3