Xcode 12 / iOS14 Widget "@main and must provide a main static function" error

Question

Using Xcode 12 trying to create Widget app extension to my project.

Upon creating new Widget target I am getting the following error:

'Widget' is annotated with @main and must provide a main static function of type () -> Void or () throws -> Void.

score 29 · Accepted Answer · answered Jun 23 '20 at 07:39

You are using name Widget, there is already a protocol called Widget in SwiftUI framework.

You should use some other name but if you really want to, add module name at start like SwiftUI.Widget

@main
struct Widget: SwiftUI.Widget {
    private let kind: String = "Widget"

    public var body: some WidgetConfiguration {
        IntentConfiguration(kind: kind, intent: ConfigurationIntent.self, provider: Provider(), placeholder: PlaceholderView()) { entry in
            WidgetEntryView(entry: entry)
        }
        .configurationDisplayName("My Widget")
        .description("This is an example widget.")
    }
}

Also @main struct SwiftUIApp: SwiftUI.App – cvb Oct 06 '20 at 15:20 — cvb, Oct 06 '20 at 15:20

score 7 · Answer 2 · answered Sep 20 '20 at 16:15

7

For anyone looking to fix the AppDelegate issue when turning on Mac for an iOS14 project - please consult : iOS Xcode 12.0 Swift 5 'AppDelegate' is annotated with @main and must provide a main static function of type () -> Void or () throws -> Void

The fix is to change "@main" to "@UIApplicationMain"

answered Sep 20 '20 at 16:15

odlh

373
4
3

For SwiftUI projects: `@UIApplicationMain may only be used on 'class' declarations` – Sound Blaster Sep 23 '20 at 06:52
So, to fix that need to use Xcode 12.2 and fresh beta of macOS 11 – Sound Blaster Sep 23 '20 at 08:33

score 2 · Answer 3 · answered Dec 25 '20 at 19:38

2

I got this exact error with the following code:

@main
struct NotesApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

The problem was I named my app logic class App.

answered Dec 25 '20 at 19:38

Alex Fine

129
7

score 0 · Answer 4 · answered Dec 09 '20 at 07:11

I've got the same error with this code :

import WidgetKit

@main
struct WidgetSale: Widget {
    let kind: String = "widgetSale"

    var body: some WidgetConfiguration {
        StaticConfiguration(kind: kind, provider: Provider()) { entry in
            widgetSaleEntryView(entry: entry)
        }
        .configurationDisplayName("My Widget")
        .description("This is an example widget.")
    }
}

I solve it by importing swiftUI at the top of the file :

import SwiftUI

Xcode 12 / iOS14 Widget "@main and must provide a main static function" error

4 Answers4