SwiftUI declarative views | Swift

SwiftUI is Apple’s modern UI framework. It is declarative, which means you describe what the interface should look like for current state. SwiftUI figures out how to update the screen when that state changes.

A basic view

import SwiftUI

struct ProfileView: View {
    let name: String

    var body: some View {
        Text("Hello, \(name)")
            .font(.title)
            .padding()
    }
}

A SwiftUI view is usually a struct. Its body returns another view.

Views are values

SwiftUI views are descriptions, not long-lived screen objects. The system can recreate view values often. That is normal.

This is why state matters. Data that must survive view recreation should live in the right state storage, not in random stored properties.

struct CounterView: View {
    @State private var count = 0

    var body: some View {
        Button("Count: \(count)") {
            count += 1
        }
    }
}

@State gives SwiftUI ownership of the stored value so it persists across body recalculations.

Modifiers

Modifiers return modified views:

Text("Saved")
    .font(.headline)
    .foregroundStyle(.green)
    .padding()

Order matters because each modifier wraps or transforms the previous view.

Keep logic out of body

body should describe UI. Move formatting, validation, networking, and business rules into models, helper methods, or view models.

var title: String {
    article.title.isEmpty ? "Untitled" : article.title
}

Small computed properties can make view code readable. Large workflows belong elsewhere.

What to carry forward

SwiftUI is declarative
views describe UI for current state
views are value descriptions and may be recreated often
body should stay focused on UI structure
modifiers transform views and order can matter
state needs explicit ownership

Next, you will learn layout and modifiers in more detail.