WidgetKit iOS 17+: Building Interactive Widgets with App Intents

import WidgetKit
import SwiftUI
import AppIntents

// The architecture relies on three main components:
// 1. Widget Timeline Provider - supplies the data
// 2. Widget View - displays the interface with Button/Toggle
// 3. App Intent - executes the action on tap

struct TaskWidget: Widget {
    // Unique widget identifier
    let kind: String = "TaskWidget"

    var body: some WidgetConfiguration {
        // StaticConfiguration for widgets without parameters
        StaticConfiguration(
            kind: kind,
            provider: TaskTimelineProvider()
        ) { entry in
            TaskWidgetView(entry: entry)
                // Required for App Intents
                .containerBackground(.fill.tertiary, for: .widget)
        }
        .configurationDisplayName("Tasks")
        .description("Manage your tasks from the home screen.")
        .supportedFamilies([.systemSmall, .systemMedium])
    }
}

import WidgetKit
import SwiftUI

// Entry representing widget state at a given moment
struct TaskEntry: TimelineEntry {
    let date: Date
    let tasks: [Task]

    // Loading state for visual feedback
    var isLoading: Bool = false
}

// Data model shared between app and widget
struct Task: Identifiable, Codable {
    let id: UUID
    var title: String
    var isCompleted: Bool
    var priority: Priority

    enum Priority: String, Codable {
        case low, medium, high
    }
}

struct TaskTimelineProvider: TimelineProvider {
    // Placeholder displayed during initial loading
    func placeholder(in context: Context) -> TaskEntry {
        TaskEntry(
            date: Date(),
            tasks: [
                Task(id: UUID(), title: "Sample task", isCompleted: false, priority: .medium)
            ]
        )
    }

    // Snapshot for widget gallery
    func getSnapshot(in context: Context, completion: @escaping (TaskEntry) -> Void) {
        let entry = TaskEntry(
            date: Date(),
            tasks: TaskDataManager.shared.fetchTasks().prefix(3).map { $0 }
        )
        completion(entry)
    }

    // Complete timeline with refresh policy
    func getTimeline(in context: Context, completion: @escaping (Timeline<TaskEntry>) -> Void) {
        let tasks = TaskDataManager.shared.fetchTasks()
        let entry = TaskEntry(date: Date(), tasks: Array(tasks.prefix(3)))

        // Refresh in 15 minutes or after user action
        let nextUpdate = Calendar.current.date(
            byAdding: .minute,
            value: 15,
            to: Date()
        ) ?? Date()

        let timeline = Timeline(
            entries: [entry],
            policy: .after(nextUpdate)
        )
        completion(timeline)
    }
}

import Foundation

final class TaskDataManager {
    // Singleton for global access
    static let shared = TaskDataManager()

    // App Group identifier configured in Xcode
    private let appGroupID = "group.com.example.taskapp"

    // UserDefaults shared between app and widget
    private var sharedDefaults: UserDefaults? {
        UserDefaults(suiteName: appGroupID)
    }

    private let tasksKey = "tasks"

    private init() {}

    // Fetch tasks from shared storage
    func fetchTasks() -> [Task] {
        guard let data = sharedDefaults?.data(forKey: tasksKey),
              let tasks = try? JSONDecoder().decode([Task].self, from: data) else {
            return []
        }
        return tasks
    }

    // Save with widget notification
    func saveTasks(_ tasks: [Task]) {
        guard let data = try? JSONEncoder().encode(tasks) else { return }
        sharedDefaults?.set(data, forKey: tasksKey)
    }

    // Update a specific task
    func updateTask(_ task: Task) {
        var tasks = fetchTasks()
        if let index = tasks.firstIndex(where: { $0.id == task.id }) {
            tasks[index] = task
            saveTasks(tasks)
        }
    }

    // Toggle completed state
    func toggleTaskCompletion(taskID: UUID) {
        var tasks = fetchTasks()
        if let index = tasks.firstIndex(where: { $0.id == taskID }) {
            tasks[index].isCompleted.toggle()
            saveTasks(tasks)
        }
    }
}

import AppIntents
import WidgetKit

// Intent to toggle task state
struct ToggleTaskIntent: AppIntent {
    // Title displayed in Siri shortcuts
    static var title: LocalizedStringResource = "Toggle task state"

    // Description for accessibility
    static var description = IntentDescription("Marks a task as completed or not completed.")

    // Parameter: ID of task to modify
    @Parameter(title: "Task ID")
    var taskID: String

    // Required initializer for AppIntent
    init() {}

    // Initializer with parameter for view creation
    init(taskID: UUID) {
        self.taskID = taskID.uuidString
    }

    // Action execution
    func perform() async throws -> some IntentResult {
        // Convert string ID to UUID
        guard let uuid = UUID(uuidString: taskID) else {
            return .result()
        }

        // Update the task
        TaskDataManager.shared.toggleTaskCompletion(taskID: uuid)

        // Request widget refresh
        WidgetCenter.shared.reloadTimelines(ofKind: "TaskWidget")

        return .result()
    }
}

import SwiftUI
import WidgetKit

struct TaskWidgetView: View {
    let entry: TaskEntry

    // Adapt to widget size
    @Environment(\.widgetFamily) var family

    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            // Header with title and counter
            headerView

            // Task list with interactive buttons
            ForEach(entry.tasks.prefix(tasksLimit)) { task in
                TaskRowView(task: task)
            }

            Spacer(minLength: 0)
        }
        .padding()
    }

    // Number of tasks based on size
    private var tasksLimit: Int {
        switch family {
        case .systemSmall: return 2
        case .systemMedium: return 3
        default: return 4
        }
    }

    private var headerView: some View {
        HStack {
            Text("Tasks")
                .font(.headline)
                .fontWeight(.bold)

            Spacer()

            // Badge with remaining task count
            let remaining = entry.tasks.filter { !$0.isCompleted }.count
            Text("\(remaining)")
                .font(.caption.bold())
                .foregroundStyle(.white)
                .padding(.horizontal, 8)
                .padding(.vertical, 4)
                .background(remaining > 0 ? Color.orange : Color.green)
                .clipShape(Capsule())
        }
    }
}

struct TaskRowView: View {
    let task: Task

    var body: some View {
        // Button with App Intent as action
        Button(intent: ToggleTaskIntent(taskID: task.id)) {
            HStack(spacing: 12) {
                // Completion indicator
                Image(systemName: task.isCompleted ? "checkmark.circle.fill" : "circle")
                    .font(.title3)
                    .foregroundStyle(task.isCompleted ? .green : .secondary)

                // Task title
                Text(task.title)
                    .font(.subheadline)
                    .strikethrough(task.isCompleted)
                    .foregroundStyle(task.isCompleted ? .secondary : .primary)
                    .lineLimit(1)

                Spacer()

                // Priority indicator
                priorityIndicator
            }
            .padding(.vertical, 6)
            .padding(.horizontal, 10)
            .background(Color(.systemBackground).opacity(0.5))
            .cornerRadius(8)
        }
        .buttonStyle(.plain)
    }

    @ViewBuilder
    private var priorityIndicator: some View {
        switch task.priority {
        case .high:
            Image(systemName: "exclamationmark.circle.fill")
                .foregroundStyle(.red)
        case .medium:
            Image(systemName: "minus.circle.fill")
                .foregroundStyle(.orange)
        case .low:
            EmptyView()
        }
    }
}

import SwiftUI
import AppIntents

// Specific intent for Toggle with explicit state
struct SetTaskCompletionIntent: AppIntent {
    static var title: LocalizedStringResource = "Set task state"

    @Parameter(title: "Task ID")
    var taskID: String

    // Target state: true = completed, false = not completed
    @Parameter(title: "Completed")
    var isCompleted: Bool

    init() {}

    init(taskID: UUID, isCompleted: Bool) {
        self.taskID = taskID.uuidString
        self.isCompleted = isCompleted
    }

    func perform() async throws -> some IntentResult {
        guard let uuid = UUID(uuidString: taskID) else {
            return .result()
        }

        var tasks = TaskDataManager.shared.fetchTasks()
        if let index = tasks.firstIndex(where: { $0.id == uuid }) {
            // Set state explicitly (not toggle)
            tasks[index].isCompleted = isCompleted
            TaskDataManager.shared.saveTasks(tasks)
        }

        WidgetCenter.shared.reloadTimelines(ofKind: "TaskWidget")
        return .result()
    }
}

struct TaskToggleRowView: View {
    let task: Task

    var body: some View {
        HStack {
            Text(task.title)
                .font(.subheadline)
                .strikethrough(task.isCompleted)

            Spacer()

            // Interactive toggle with intent
            Toggle(
                isOn: task.isCompleted,
                intent: SetTaskCompletionIntent(
                    taskID: task.id,
                    isCompleted: !task.isCompleted
                )
            )
            .toggleStyle(.switch)
            .labelsHidden()
        }
        .padding(.vertical, 4)
    }
}

import SwiftUI
import WidgetKit

struct AnimatedTaskRowView: View {
    let task: Task

    var body: some View {
        Button(intent: ToggleTaskIntent(taskID: task.id)) {
            HStack(spacing: 12) {
                // Icon with transition animation
                Image(systemName: task.isCompleted ? "checkmark.circle.fill" : "circle")
                    .font(.title3)
                    .foregroundStyle(task.isCompleted ? .green : .secondary)
                    // Icon animation on change
                    .contentTransition(.symbolEffect(.replace))

                Text(task.title)
                    .font(.subheadline)
                    .strikethrough(task.isCompleted)
                    .foregroundStyle(task.isCompleted ? .secondary : .primary)
                    // Text animation
                    .contentTransition(.opacity)

                Spacer()
            }
            .padding(.vertical, 6)
            .padding(.horizontal, 10)
            .background(
                RoundedRectangle(cornerRadius: 8)
                    .fill(task.isCompleted ? Color.green.opacity(0.1) : Color.clear)
            )
            // Background animation
            .animation(.easeInOut(duration: 0.3), value: task.isCompleted)
        }
        .buttonStyle(.plain)
    }
}

// Widget with animated invalidation
struct AnimatedTaskWidget: Widget {
    let kind: String = "AnimatedTaskWidget"

    var body: some WidgetConfiguration {
        StaticConfiguration(
            kind: kind,
            provider: TaskTimelineProvider()
        ) { entry in
            AnimatedTaskWidgetView(entry: entry)
                .containerBackground(.fill.tertiary, for: .widget)
        }
        .configurationDisplayName("Animated Tasks")
        .description("Widgets with smooth animations.")
        .supportedFamilies([.systemSmall, .systemMedium, .systemLarge])
        // Enable content animations
        .contentMarginsDisabled()
    }
}

struct AnimatedTaskWidgetView: View {
    let entry: TaskEntry

    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            headerView

            ForEach(entry.tasks) { task in
                AnimatedTaskRowView(task: task)
            }

            Spacer(minLength: 0)
        }
        .padding()
    }

    private var headerView: some View {
        HStack {
            Text("Tasks")
                .font(.headline.bold())

            Spacer()

            let completed = entry.tasks.filter(\.isCompleted).count
            let total = entry.tasks.count

            // Animated progress
            Text("\(completed)/\(total)")
                .font(.caption.bold())
                .foregroundStyle(.secondary)
                .contentTransition(.numericText())
        }
    }
}

import WidgetKit
import SwiftUI
import AppIntents

// Configuration exposed to user
struct TaskWidgetConfigurationIntent: WidgetConfigurationIntent {
    static var title: LocalizedStringResource = "Task configuration"
    static var description = IntentDescription("Customize task display.")

    // Filter by priority
    @Parameter(title: "Priority", default: .all)
    var priorityFilter: PriorityFilter

    // Show completed tasks
    @Parameter(title: "Show completed", default: true)
    var showCompleted: Bool

    // Maximum number of tasks
    @Parameter(title: "Task count", default: 3)
    var maxTasks: Int
}

// Enum for priority filter
enum PriorityFilter: String, AppEnum {
    case all
    case high
    case medium
    case low

    static var typeDisplayRepresentation: TypeDisplayRepresentation = "Priority"

    static var caseDisplayRepresentations: [PriorityFilter: DisplayRepresentation] = [
        .all: "All",
        .high: "High",
        .medium: "Medium",
        .low: "Low"
    ]
}

// Provider adapted to configuration
struct ConfigurableTaskProvider: AppIntentTimelineProvider {
    typealias Entry = TaskEntry
    typealias Intent = TaskWidgetConfigurationIntent

    func placeholder(in context: Context) -> TaskEntry {
        TaskEntry(date: Date(), tasks: [])
    }

    func snapshot(for configuration: TaskWidgetConfigurationIntent, in context: Context) async -> TaskEntry {
        let tasks = filteredTasks(for: configuration)
        return TaskEntry(date: Date(), tasks: tasks)
    }

    func timeline(for configuration: TaskWidgetConfigurationIntent, in context: Context) async -> Timeline<TaskEntry> {
        let tasks = filteredTasks(for: configuration)
        let entry = TaskEntry(date: Date(), tasks: tasks)

        let nextUpdate = Date().addingTimeInterval(15 * 60)
        return Timeline(entries: [entry], policy: .after(nextUpdate))
    }

    // Apply configuration filters
    private func filteredTasks(for config: TaskWidgetConfigurationIntent) -> [Task] {
        var tasks = TaskDataManager.shared.fetchTasks()

        // Filter by priority
        if config.priorityFilter != .all {
            let priority = Task.Priority(rawValue: config.priorityFilter.rawValue) ?? .medium
            tasks = tasks.filter { $0.priority == priority }
        }

        // Filter completed if needed
        if !config.showCompleted {
            tasks = tasks.filter { !$0.isCompleted }
        }

        // Limit count
        return Array(tasks.prefix(config.maxTasks))
    }
}

// Widget with user configuration
struct ConfigurableTaskWidget: Widget {
    let kind: String = "ConfigurableTaskWidget"

    var body: some WidgetConfiguration {
        // AppIntentConfiguration for configurable widgets
        AppIntentConfiguration(
            kind: kind,
            intent: TaskWidgetConfigurationIntent.self,
            provider: ConfigurableTaskProvider()
        ) { entry in
            TaskWidgetView(entry: entry)
                .containerBackground(.fill.tertiary, for: .widget)
        }
        .configurationDisplayName("Custom Tasks")
        .description("Filter and customize your tasks.")
        .supportedFamilies([.systemSmall, .systemMedium, .systemLarge])
    }
}

import AppIntents
import WidgetKit

struct ToggleTaskWithFeedbackIntent: AppIntent {
    static var title: LocalizedStringResource = "Toggle task with feedback"

    @Parameter(title: "Task ID")
    var taskID: String

    init() {}

    init(taskID: UUID) {
        self.taskID = taskID.uuidString
    }

    func perform() async throws -> some IntentResult & ReturnsValue<Bool> {
        guard let uuid = UUID(uuidString: taskID) else {
            // Return silent failure
            return .result(value: false)
        }

        // Simulate async operation (server sync for example)
        do {
            try await Task.sleep(for: .milliseconds(100))

            TaskDataManager.shared.toggleTaskCompletion(taskID: uuid)
            WidgetCenter.shared.reloadTimelines(ofKind: "TaskWidget")

            return .result(value: true)
        } catch {
            // Error: don't update widget
            return .result(value: false)
        }
    }
}

// View with loading state
struct TaskRowWithLoadingView: View {
    let task: Task
    @State private var isLoading = false

    var body: some View {
        Button(intent: ToggleTaskIntent(taskID: task.id)) {
            HStack(spacing: 12) {
                // Conditional indicator
                Group {
                    if isLoading {
                        ProgressView()
                            .scaleEffect(0.8)
                    } else {
                        Image(systemName: task.isCompleted ? "checkmark.circle.fill" : "circle")
                            .foregroundStyle(task.isCompleted ? .green : .secondary)
                    }
                }
                .frame(width: 24, height: 24)

                Text(task.title)
                    .font(.subheadline)
                    .strikethrough(task.isCompleted)

                Spacer()
            }
            .padding(.vertical, 6)
            .padding(.horizontal, 10)
            .background(Color(.systemBackground).opacity(0.5))
            .cornerRadius(8)
        }
        .buttonStyle(.plain)
        .disabled(isLoading)
        .opacity(isLoading ? 0.6 : 1.0)
    }
}

import WidgetKit
import SwiftUI

// 1. Always invalidate cache after modification
final class WidgetRefreshManager {
    static func refreshAllWidgets() {
        // Refresh all app widgets
        WidgetCenter.shared.reloadAllTimelines()
    }

    static func refreshWidget(kind: String) {
        // Refresh specific widget
        WidgetCenter.shared.reloadTimelines(ofKind: kind)
    }

    // Call from app after data modification
    static func notifyDataChanged() {
        Task { @MainActor in
            refreshAllWidgets()
        }
    }
}

// 2. Limit view complexity
struct OptimizedWidgetView: View {
    let entry: TaskEntry

    var body: some View {
        // Prefer simple views without GeometryReader
        VStack(alignment: .leading, spacing: 8) {
            ForEach(entry.tasks.prefix(3)) { task in
                // Lightweight components
                minimalTaskRow(task)
            }
        }
        .padding()
    }

    // Minimal view for performance
    @ViewBuilder
    private func minimalTaskRow(_ task: Task) -> some View {
        Button(intent: ToggleTaskIntent(taskID: task.id)) {
            HStack {
                Image(systemName: task.isCompleted ? "checkmark.circle.fill" : "circle")
                Text(task.title)
                    .lineLimit(1)
            }
        }
        .buttonStyle(.plain)
    }
}

// 3. Use @AppStorage for simple state
struct QuickSettingsWidgetView: View {
    // Direct access to shared UserDefaults
    @AppStorage("showCompletedTasks", store: UserDefaults(suiteName: "group.com.example.app"))
    private var showCompleted = true

    var body: some View {
        // State persists between refreshes
        Text(showCompleted ? "Showing all" : "Hiding completed")
    }
}

// 4. Pre-calculate data in provider
struct OptimizedTaskEntry: TimelineEntry {
    let date: Date
    let tasks: [Task]

    // Pre-calculated data
    let completedCount: Int
    let pendingCount: Int
    let highPriorityCount: Int

    init(date: Date, tasks: [Task]) {
        self.date = date
        self.tasks = tasks

        // Calculations performed once
        self.completedCount = tasks.filter(\.isCompleted).count
        self.pendingCount = tasks.filter { !$0.isCompleted }.count
        self.highPriorityCount = tasks.filter { $0.priority == .high && !$0.isCompleted }.count
    }
}