When to use didset or get set when using @IBInspectable

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After looking at different tutorial. i don't know when to use didset or get set to update the variable. Could anyone explain a little bit more detail for when to use didset or get set?

 @IBInspectable var circleColor: UIColor = UIColor.redColor() {
    didSet { //after properties are set in storyboard, update here
        circleLayer.strokeColor = circleColor.CGColor
        self.toggleButon()
    }
}
/**
    Radius of RadioButton circle.
*/
@IBInspectable var circleRadius: CGFloat = 5.0
@IBInspectable var cornerRadius: CGFloat {
    get {
        return layer.cornerRadius
    }
    set {
        layer.cornerRadius = newValue
        layer.masksToBounds = newValue > 0
    }
}

for circle radius, it doesn't have to use didset to update its value. i can't get it.

Here i am giving you one example and try to explain you how to use, hope it will helpful for you.
I am using this class for UIView here for did set and get set with Story Board my class name here "MyCustomView"
import Foundation
import UIKit
import QuartzCore

/// Computed properties, based on the backing CALayer property, that are visible in Interface Builder.
@IBDesignable public class MyCustomView: UIView {
    /// When positive, the background of the layer will be drawn with rounded corners. Also effects the mask generated by the `masksToBounds' property. Defaults to zero. Animatable.
    @IBInspectable var cornerRadius: Double {
        get {
            return Double(self.layer.cornerRadius)
        }
        set {
            self.layer.cornerRadius = CGFloat(newValue)
        }
    }
    
    /// The width of the layer's border, inset from the layer bounds. The border is composited above the layer's content and sublayers and includes the effects of the `cornerRadius' property. Defaults to zero. Animatable.
    @IBInspectable var borderWidth: Double {
        get {
            return Double(self.layer.borderWidth)
        }
        set {
            self.layer.borderWidth = CGFloat(newValue)
        }
    }
    
    /// The color of the layer's border. Defaults to opaque black. Colors created from tiled patterns are supported. Animatable.
    @IBInspectable var borderColor: UIColor? {
        get {
            return UIColor(CGColor: self.layer.borderColor!)
        }
        set {
            self.layer.borderColor = newValue?.CGColor
        }
    }
    
    /// The color of the shadow. Defaults to opaque black. Colors created from patterns are currently NOT supported. Animatable.
    @IBInspectable var shadowColor: UIColor? {
        get {
            return UIColor(CGColor: self.layer.shadowColor!)
        }
        set {
            self.layer.shadowColor = newValue?.CGColor
        }
    }
    
    /// The opacity of the shadow. Defaults to 0. Specifying a value outside the [0,1] range will give undefined results. Animatable.
    @IBInspectable var shadowOpacity: Float {
        get {
            return self.layer.shadowOpacity
        }
        set {
            self.layer.shadowOpacity = newValue
        }
    }
    
    /// The shadow offset. Defaults to (0, -3). Animatable.
    @IBInspectable var shadowOffset: CGSize {
        get {
            return self.layer.shadowOffset
        }
        set {
            self.layer.shadowOffset = newValue
        }
    }
    
    /// The blur radius used to create the shadow. Defaults to 3. Animatable.
    @IBInspectable var shadowRadius: Double {
        get {
            return Double(self.layer.shadowRadius)
        }
        set {
            self.layer.shadowRadius = CGFloat(newValue)
        }
    }
}

And you can use this with story board import this class with your "UIView"

after you will see some and you directly set here view cornet radius, shadow and Shadow

and result you can see inside your storyboard directly without running code

Output here from this code

Swift IBInspectable didSet versus get/set, So, when would you want to use a stored property with an observer? One condition especially applicable to IBInspectable is when the� For this we have to use IBInspectable attribute. Let’s see how we can add them. Let’s see how we can add them. @IBInspectable public var cornerRadius: CGFloat = 2.0 { didSet { self.layer

This answer explains the difference in usage of set vs didSet quite clearly.

IN SUMMARY

willSet should be used for doing something before the value is set. (the value is not updated at this point).

set is to update the value

didSet if you want to do anything after the value is set (the value has been updated at this point)

ALSO

if you implement set, you will also need to implement get

but didSet can also be used without having to implement any other method

A more insightful look into IBDesignable and IBInspectable, In this article -in addition to the usage- I'd like to go into a little bit more detail, view class, and add your desired properties with their IBInspectable annotations. @IBInspectable public var cornerRadius: CGFloat = 0.0 { didSet { layer. This is because iOS uses Key-Value-Coding to set the IBInspectable� extension UIView {@IBInspectable var corner Radius: CGFloat {get {return layer. corner Radius} set {layer. corner Radius = new Value layer. masks To Bounds = new Value > 0}}} Presto! A configurable border radius on any UIView you create. IBDesignable. As if that weren’t enough, IBDesignable custom views also debut in Xcode 6.

IBInspectable / IBDesignable, With IBInspectable and IBDesignable, Xcode 6 makes just such a substitution, The key path, type, and value of an attribute need to be set on each instance, @IBInspectable var cornerRadius: CGFloat = 0 { didSet { layer. @IBInspectable – Allows us to access the property from the Attribute Inspector when the view is highlighted. The rest of the code is simply creating two new properties,viewBackgroundColour and cornerRadius. We then use didset to change the view’s corresponding properties when either cornerRadius or viewBackgroundColour are changed.

Properties — The Swift Programming Language (Swift 5.3), However, properties can also be associated with the type itself. You can also use a property wrapper to reuse code in the getter and setter of multiple You can also set and modify the initial value for a stored property during initialization. The willSet and didSet observers of superclass properties are called when a� To make them work, we use either didSet to execute code when a property has just been set, or willSet to execute code before a property has been set. In our case, we want to add a property observer to our score property so that we update the score label whenever the score value was changed. So, change your score property to this:

Custom UISegmentedControl In Swift, Have you gotten tired of the standard UISegmentedControl in swift, and just wish Creating Custom UIView's programmatically; Use @IBDesignable and Note: I'm using 'didSet' in the variable initializer. Set Button Title @IBInspectable available from iOS 8.0. The @ IBInspectable properties provide the new class which is old feature of User define runtime attribute. This is powerful mechanisms apply for XIB, NIB or StoryBoard.

One thing to note is that willSet and didSet will never get called on setting the initial value of the property. It will only get called whenever you set the property by assigning a new value to it.

Comments
  • in my sample code, it doesn't have to use didset or getset to update the circle radius. but i can also change it by setting in storyboard. so i can't get it
  • Please check you imported inside you UIView like @IBDesignable public class ClassName of your IBDesignable? otherwise you can use my code.
  • i think you get me wrong. i am trying to say i that i can change the circle radius in attributes inspector even though i didn't use didset or getset to update the value in my code