SwiftUI view with optional default parameter

Question

I am trying to replicate the way we can create a function with a default optional parameter in swiftui.

func greet(_ person: String, nicely: Bool = true) {
    if nicely == true {
        print("Hello, \(person)!")
    } else {
        print("Oh no, it's \(person) again...")
    }
}

Which could be called in two different ways

greet("Taylor")
greet("Taylor", nicely: false)

Is it possible to create a SwiftUI view with this same logic? I would like to create a component that has a 'default optional' parameter so I could call it as:

DividerItem(...)
DividerItem(..., isBold: true)

Many thanks!

davidev · Accepted Answer · 2020-11-18 09:35:54Z

10

Here you go... just define the variables of your View, give them default and you can call them with two different intializations

struct ContentView: View {
    
    var body : some View {
        DividerItem(text: "Hello World", isBold: true)
        DividerItem(text: "Hello Second World")
    }
}


struct DividerItem : View {
    
    var text : String
    var isBold = false
    
    var body : some View {
        Text(text)
            .fontWeight(self.isBold ? .bold : .medium)
    }
}

answered Nov 18, 2020 at 9:35

davidev

8,6855 gold badges35 silver badges70 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

jmrueda Over a year ago

Thank you for the answer! I was slightly confused, trying var isBold?: Bool = true

davidev Over a year ago

Thats two different things. You might declare your isBold as optional. Then it can be nil. Hence, you won't need to declare a default value aswell, as the default value is nil. If you want to make sure isBold has always a valid value, you provide a default parameter without declaring it was optional.

Joakim Danielson · Accepted Answer · 2020-11-18 10:44:25Z

4

You can create a custom initialiser for your view

struct DividerItem : View {
    var isBold: Bool
    // other properties

    init(/* other params */ isBold: Bool = false) {
        self.isBold = isBold
    }

    var body: some View {
        //....
    }
}

and then call it with or without the boolean parameter

DividerItem(/* other params */)
DividerItem(/* other params */ isBold: true)

edited Nov 18, 2020 at 10:44

answered Nov 18, 2020 at 10:07

Joakim Danielson

53k5 gold badges36 silver badges79 bronze badges

2 Comments

jmrueda Over a year ago

What are the differences between both solutions? I personally prefer the first one as it seems less coding. Thank you.

Joakim Danielson Over a year ago

@jmrueda Mostly a matter of taste and I primarily posted this to show there is another option. And sometimes you might need to have an init anyway for other reasons so then this is usable

vikingosegundo · Accepted Answer · 2024-05-25 13:39:47Z

struct MetricCardView: View {
    var title: String
    var value: String
    var color: Color
    var width: CGFloat
    var iconName: String?
    var iconDecription: String?


    var body: some View {
        VStack {

    if let iconName = iconName, let iconDecription = iconDecription {
                Label(iconName, systemImage: iconDecription)
            }
           
            Text(title)
                .font(.headline)
            Text(value)
                .font(.largeTitle)
                .fontWeight(.bold)
        }
        .frame(width: width, height: 100)
        .background(color.opacity(0.2))
        .cornerRadius(10)
    }
}

now you can call the MetricCardView() and for any of the two var marks as question mark

Collectives™ on Stack Overflow

SwiftUI view with optional default parameter

3 Answers 3

2 Comments

2 Comments

Comments

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

2 Comments

Comments

Related