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Model Availability Gate

A view that shows its content when the on-device model can answer, and otherwise explains why not and what the person can do.

Model Availability Gate, playing
Download .swift
Uses
SystemLanguageModelSystemLanguageModel.AvailabilityContentUnavailableView
Origin
Original work
Found by
foundation models · apple intelligence · on-device model · availability · unavailable state · gate · llm · modelo en el dispositivo · apple intelligence · disponibilidad · estado no disponible · inteligencia artificial · comprobación

Description

Section titled “Description”

Shows its content when the on-device model can answer. Otherwise it explains why not and what the person can do.

The system does not notify changes in availability, so the view checks again when the app becomes active and every few seconds while the model downloads.

Usage

Section titled “Usage”
@available(iOS 26, *)
struct ModelAvailabilityGateDemo: View {
    private enum Sample: String, CaseIterable, Identifiable {
        case ready = "Ready"
        case device = "Device"
        case off = "Off"
        case preparing = "Preparing"


        var id: Self { self }


        var availability: SystemLanguageModel.Availability {
            switch self {
            case .ready: .available
            case .device: .unavailable(.deviceNotEligible)
            case .off: .unavailable(.appleIntelligenceNotEnabled)
            case .preparing: .unavailable(.modelNotReady)
            }
        }
    }


    @State private var sample = Sample.device
    @State private var autoPlays = true
    @Environment(\.accessibilityReduceMotion) private var reduceMotion


    private var pickerSelection: Binding<Sample> {
        Binding(get: { sample }, set: { newValue in
            autoPlays = false
            sample = newValue
        })
    }


    var body: some View {
        VStack(spacing: 20) {
            ZStack {
                RoundedRectangle(cornerRadius: 28, style: .continuous)
                    .fill(.background)
                    .shadow(color: .indigo.opacity(0.18), radius: 22, y: 10)
                    .accessibilityHidden(true)


                ModelAvailabilityGate(availability: sample.availability) {
                    VStack(spacing: 14) {
                        Image(systemName: "sparkles")
                            .font(.largeTitle)
                            .foregroundStyle(.indigo.gradient)
                            .accessibilityHidden(true)
                        Text("The model is ready")
                            .font(.title2.bold())
                        Text("Your feature appears here.")
                            .font(.body)
                            .foregroundStyle(.secondary)
                    }
                    .padding()
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                }
                .id(sample)
                .transition(.opacity)
            }


            Picker("Availability", selection: pickerSelection) {
                ForEach(Sample.allCases) { Text($0.rawValue).tag($0) }
            }
            .pickerStyle(.segmented)
        }
        .padding(20)
        .background(LinearGradient(colors: [.indigo.opacity(0.14), .teal.opacity(0.1)], startPoint: .top, endPoint: .bottom))
        .task(id: autoPlays && !reduceMotion) {
            guard autoPlays, !reduceMotion else { return }
            while !Task.isCancelled {
                try? await Task.sleep(for: .seconds(1.2))
                guard !Task.isCancelled else { return }
                let all = Sample.allCases
                let next = ((all.firstIndex(of: sample) ?? 0) + 1) % all.count
                withAnimation(.smooth(duration: 0.3)) { sample = all[next] }
            }
        }
    }
}


@available(iOS 26, *)

API reference

Section titled “API reference”
ParameterTypeDefaultDescription
availabilitySystemLanguageModel.Availability?nilLeave it nil to read the real model. Pass a value to force a state.
content() -> ContentRequired

Code

Section titled “Code”

Copy this code into your project, or download the file.

ModelAvailabilityGate.swift
// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Oscar Canton and SwiftUI Blocks contributors


import FoundationModels
import SwiftUI


/// Shows its content when the on-device model can answer. Otherwise it explains
/// why not and what the person can do.
///
/// The system does not notify changes in availability, so the view checks again
/// when the app becomes active and every few seconds while the model downloads.
@available(iOS 26, *)
struct ModelAvailabilityGate<Content: View>: View {
    /// Leave it `nil` to read the real model. Pass a value to force a state.
    var availability: SystemLanguageModel.Availability? = nil
    @ViewBuilder var content: () -> Content


    @State private var liveAvailability = SystemLanguageModel.default.availability
    @Environment(\.scenePhase) private var scenePhase


    var body: some View {
        Group {
            switch availability ?? liveAvailability {
            case .available:
                content()
            case .unavailable(let reason):
                // A long explanation at the largest text sizes stays reachable.
                ViewThatFits(in: .vertical) {
                    explanation(for: reason)
                    ScrollView { explanation(for: reason) }
                }
            }
        }
        .task(id: scenePhase) {
            guard availability == nil else { return }
            liveAvailability = SystemLanguageModel.default.availability
            while liveAvailability == .unavailable(.modelNotReady) {
                try? await Task.sleep(for: .seconds(3))
                guard !Task.isCancelled else { return }
                liveAvailability = SystemLanguageModel.default.availability
            }
        }
    }


    @ViewBuilder
    private func explanation(for reason: SystemLanguageModel.Availability.UnavailableReason) -> some View {
        switch reason {
        case .deviceNotEligible:
            ContentUnavailableView(
                "Not available on this device",
                systemImage: "iphone.slash",
                description: Text("This feature needs a device that supports Apple Intelligence. Everything else in the app keeps working.")
            )
        case .appleIntelligenceNotEnabled:
            ContentUnavailableView(
                "Apple Intelligence is off",
                systemImage: "sparkles",
                description: Text("Open the Settings app, turn on Apple Intelligence, then come back to use this feature.")
            )
        case .modelNotReady:
            ContentUnavailableView {
                Label("Getting the model ready", systemImage: "arrow.down.circle")
            } description: {
                Text("The model is still downloading. This screen updates by itself when it finishes.")
            } actions: {
                ProgressView()
                    .accessibilityLabel("Preparing the model")
            }
        @unknown default:
            ContentUnavailableView(
                "Not available right now",
                systemImage: "exclamationmark.circle",
                description: Text("The on-device model cannot answer at the moment. Try again later.")
            )
        }
    }
}


// MARK: - Demo


@available(iOS 26, *)
struct ModelAvailabilityGateDemo: View {
    private enum Sample: String, CaseIterable, Identifiable {
        case ready = "Ready"
        case device = "Device"
        case off = "Off"
        case preparing = "Preparing"


        var id: Self { self }


        var availability: SystemLanguageModel.Availability {
            switch self {
            case .ready: .available
            case .device: .unavailable(.deviceNotEligible)
            case .off: .unavailable(.appleIntelligenceNotEnabled)
            case .preparing: .unavailable(.modelNotReady)
            }
        }
    }


    @State private var sample = Sample.device
    @State private var autoPlays = true
    @Environment(\.accessibilityReduceMotion) private var reduceMotion


    private var pickerSelection: Binding<Sample> {
        Binding(get: { sample }, set: { newValue in
            autoPlays = false
            sample = newValue
        })
    }


    var body: some View {
        VStack(spacing: 20) {
            ZStack {
                RoundedRectangle(cornerRadius: 28, style: .continuous)
                    .fill(.background)
                    .shadow(color: .indigo.opacity(0.18), radius: 22, y: 10)
                    .accessibilityHidden(true)


                ModelAvailabilityGate(availability: sample.availability) {
                    VStack(spacing: 14) {
                        Image(systemName: "sparkles")
                            .font(.largeTitle)
                            .foregroundStyle(.indigo.gradient)
                            .accessibilityHidden(true)
                        Text("The model is ready")
                            .font(.title2.bold())
                        Text("Your feature appears here.")
                            .font(.body)
                            .foregroundStyle(.secondary)
                    }
                    .padding()
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                }
                .id(sample)
                .transition(.opacity)
            }


            Picker("Availability", selection: pickerSelection) {
                ForEach(Sample.allCases) { Text($0.rawValue).tag($0) }
            }
            .pickerStyle(.segmented)
        }
        .padding(20)
        .background(LinearGradient(colors: [.indigo.opacity(0.14), .teal.opacity(0.1)], startPoint: .top, endPoint: .bottom))
        .task(id: autoPlays && !reduceMotion) {
            guard autoPlays, !reduceMotion else { return }
            while !Task.isCancelled {
                try? await Task.sleep(for: .seconds(1.2))
                guard !Task.isCancelled else { return }
                let all = Sample.allCases
                let next = ((all.firstIndex(of: sample) ?? 0) + 1) % all.count
                withAnimation(.smooth(duration: 0.3)) { sample = all[next] }
            }
        }
    }
}


@available(iOS 26, *)
#Preview {
    ModelAvailabilityGateDemo()
}