The 7 SwiftUI Mistakes I See Every Junior Developer Make (And How to Fix Them)

I've reviewed hundreds of SwiftUI projects. The same mistakes keep showing up — and they're not the ones you'd expect.

These aren't syntax errors. They're architectural decisions that seem fine at first but create real pain as your app grows.

Mistake #1: Putting Everything in the View

This is the most common one. Views that are 300+ lines with networking calls, state management, data transformation, and UI all mixed together.

The problem:

struct ProfileView: View {
    @State private var user: User?
    @State private var isLoading = false
    @State private var posts: [Post] = []
    @State private var error: String?

    var body: some View {
        VStack {
            // 200 lines of UI code mixed with logic
        }
        .onAppear {
            Task {
                isLoading = true
                let url = URL(string: "https://api.example.com/user")!
                let (data, _) = try await URLSession.shared.data(from: url)
                user = try JSONDecoder().decode(User.self, from: data)
                // ... more networking code
            }
        }
    }
}

The fix: Use MVVM. Your View should only describe UI. Everything else goes in a ViewModel.

@MainActor
class ProfileViewModel: ObservableObject {
    @Published var user: User?
    @Published var isLoading = false
    @Published var error: String?

    func loadProfile() async {
        isLoading = true
        defer { isLoading = false }
        // All logic lives here
    }
}

struct ProfileView: View {
    @StateObject private var vm = ProfileViewModel()

    var body: some View {
        // Clean UI code only
    }
}

Mistake #2: Abusing @State for Everything

@State is for local, view-owned data. If data needs to be shared between views or persisted, you need a different tool.

Rule of thumb:

• Data owned by this view only → @State
• Data passed from parent → @Binding or let
• Shared data (ViewModel) → @StateObject / @ObservedObject
• App-wide data → @EnvironmentObject

Getting this wrong leads to data being out of sync across your app.

Mistake #3: Not Breaking Down Views

If your view body has more than ~50 lines, it probably needs to be broken into subviews.

Don't do this:

var body: some View {
    VStack {
        // Header section (30 lines)
        // Profile card (40 lines)  
        // Stats section (25 lines)
        // Posts list (50 lines)
        // Footer (20 lines)
    }
}

Do this:

var body: some View {
    VStack {
        HeaderSection()
        ProfileCard(user: user)
        StatsSection(stats: stats)
        PostsList(posts: posts)
        FooterView()
    }
}

Smaller views = easier testing, better previews, cleaner diffs.

Mistake #4: Ignoring the Environment

SwiftUI's environment system is incredibly powerful but underused. Instead of passing data through 5 levels of view hierarchy, inject it once.

// Instead of prop drilling:
ParentView(theme: theme) → ChildView(theme: theme) → GrandchildView(theme: theme)

// Use environment:
ParentView()
    .environmentObject(theme)

// Any descendant can access it:
struct GrandchildView: View {
    @EnvironmentObject var theme: ThemeManager
}

Mistake #5: Fighting Navigation Instead of Embracing It

Pre-iOS 16 navigation was painful. But many developers still use old patterns when NavigationStack exists.

// Modern navigation pattern
NavigationStack(path: $router.path) {
    RootView()
        .navigationDestination(for: Route.self) { route in
            switch route {
            case .profile(let id): ProfileView(id: id)
            case .settings: SettingsView()
            case .detail(let item): DetailView(item: item)
            }
        }
}

This gives you programmatic navigation, deep linking support, and clean architecture.

Mistake #6: Not Using ViewModifiers

If you're applying the same set of modifiers to multiple views, create a custom ViewModifier.

struct CardStyle: ViewModifier {
    func body(content: Content) -> some View {
        content
            .padding()
            .background(Color(.systemBackground))
            .cornerRadius(12)
            .shadow(color: .black.opacity(0.1), radius: 8, y: 4)
    }
}

extension View {
    func cardStyle() -> some View {
        modifier(CardStyle())
    }
}

// Usage: clean and consistent
ProfileCard().cardStyle()
StatsCard().cardStyle()

Mistake #7: Skipping Previews

Previews aren't just a nice-to-have. They're your fastest feedback loop. Every view should have a preview with realistic data.

#Preview {
    ProfileView()
        .environmentObject(ThemeManager())
        .environmentObject(Router())
}

#Preview("Loading State") {
    ProfileView()
        .environmentObject(ThemeManager())
}

#Preview("Error State") {
    ProfileView()
        .environmentObject(ThemeManager())
}

Preview every state: loading, error, empty, populated. Your future self will thank you.

The Pattern

Notice something? Most of these mistakes come from the same root cause: treating SwiftUI like UIKit.

SwiftUI has its own mental model. The faster you adopt it, the better your code becomes.

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I've built 27 products with SwiftUI and packaged all these patterns into production-ready templates and components. If you want to skip the learning curve and write clean SwiftUI from day one:

t.me/SwiftUIDaily — daily tips, code reviews, and ready-to-use SwiftUI resources.

Which of these mistakes have you made? (No judgment — I made all of them.) Share your experience in the comments.