Sample CodeiOS, iPadOS, Mac CatalystReviewed 2026-07-21View on Apple Developer

Managing location-based reminders

At a glance

Item Summary
Purpose Access reminders set up with geofence-enabled alarms on a person’s calendars.
App architecture A Swift sample with the source-visible chain LocationBasedRemindersAppContentViewLocationManagerEventKit APIs.
Main patterns Delegate or data-source callbacks, Central store, Binding-based state propagation, Actor-isolated state
Project style 32 scanned source file(s) across Swift, organized around ranked entry, type, and file boundaries.

Project structure

Source bundle/
└── LocationBasedReminders/
    ├── LocationBasedRemindersApp.swift
    ├── ReminderStore.swift
    ├── ReminderStoreManager.swift
    ├── ContentView.swift
    ├── LocationManager.swift
    ├── MainView.swift
    ├── MapView.swift
    ├── SourceModel.swift
    ├── WelcomeView.swift
    ├── MapAnnotation.swift
    ├── AnnotationImage.swift
    └── AppSettingsLink.swift

Structure observations

  • Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
  • Primary languages: Swift.
  • The verified tree contains 4 project/configuration file(s) and 33 source declaration(s).

Overall architecture

Reference code

LocationBasedReminders/LocationBasedRemindersApp.swift:10 — architecture anchor

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

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into EventKit.

Ownership and state

Ownership evidence

LocationBasedReminders/ReminderStore.swift:29 — stored dependency or nearest verified ownership anchor

actor ReminderStore {
    let eventStore: EKEventStore
    // ...
}
Owner Object or state Relationship Mutation authority
ReminderStore EKEventStore (eventStore) stores or receives Initialized by the owner; the binding is immutable
ReminderStoreManager ReminderStore (dataStore) stores or receives Initialized by the owner; the binding is immutable
ReminderStoreManager Logger (logger) creates and retains Initialized by the owner; the binding is immutable
ContentView ReminderStoreManager (manager) owns wrapper-managed state Owning lexical scope

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Class and protocol design

LocationBasedReminders/LocationBasedRemindersApp.swift:11 — representative type boundary

struct LocationBasedRemindersApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}
Type Responsibility Depends on or conforms to
LocationBasedRemindersApp Application entry and top-level composition App
ReminderStore Centralized state or persistence access Concrete collaborators/imported frameworks
ReminderStoreManager Long-lived feature or framework coordination Concrete collaborators/imported frameworks
ContentView User-interface presentation and input forwarding View
LocationManager Long-lived feature or framework coordination NSObject
MainView User-interface presentation and input forwarding View
MapView User-interface presentation and input forwarding View
SourceModel Feature data or observable state Identifiable, Hashable, Sendable
WelcomeView User-interface presentation and input forwarding View
ReminderStoreError Represents feature failure conditions Error

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Symbol Access Verified effect Likely rationale
openURL (LocationBasedReminders/AppSettingsLink.swift:12) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: keep state mutation or dependency lifetime inside the owning implementation.
manager (LocationBasedReminders/AppSettingsLink.swift:13) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: keep state mutation or dependency lifetime inside the owning implementation.
navigatetoSettings (LocationBasedReminders/AppSettingsLink.swift:26) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: hide an implementation step that is not part of the collaboration surface.
navigateButton (LocationBasedReminders/AppSettingsLink.swift:33) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: keep state mutation or dependency lifetime inside the owning implementation.

Reference code

LocationBasedReminders/AppSettingsLink.swift:12 — representative boundary

    @Environment(\.openURL) private var openURL

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Logic Owning type or file Placement rationale
Application entry and top-level composition LocationBasedRemindersApp The source’s App suffix makes this role explicit.
Long-lived feature or framework coordination LocationManager, ReminderStoreManager The source’s Manager suffix makes this role explicit.
Feature data or observable state SourceModel The source’s Model suffix makes this role explicit.
Centralized state or persistence access ReminderStore The source’s Store suffix makes this role explicit.
User-interface presentation and input forwarding ContentView, MainView, MapView, WelcomeView The source’s View suffix makes this role explicit.

Design patterns

Pattern Source evidence Purpose or tradeoff
Delegate or data-source callbacks LocationBasedReminders/LocationManager.swift:33 Callback protocols invert event delivery back into the sample’s owner.
Central store LocationBasedReminders/ReminderStore.swift:28 A store-named type centralizes feature state or persistence.
Binding-based state propagation LocationBasedReminders/DeleteCompletedRemindersButton.swift:11 A binding exposes controlled read/write access while the upstream owner remains authoritative.
Actor-isolated state LocationBasedReminders/ReminderStore.swift:28 Actor annotations make the concurrency ownership boundary explicit.

Naming conventions

  • Types: App: LocationBasedRemindersApp; Manager: LocationManager, ReminderStoreManager; Model: SourceModel; Store: ReminderStore; View: ContentView, MainView, MapView, WelcomeView.
  • Protocols: no local protocol declaration in the scanned source.
  • Methods: requestAccess, defaultList, createReminder, save, saveList, ekReminder, fetchReminders, completeLocationReminder.
  • Files: LocationBasedReminders/LocationBasedRemindersApp.swift, LocationBasedReminders/ReminderStore.swift, LocationBasedReminders/ReminderStoreManager.swift, LocationBasedReminders/ContentView.swift, LocationBasedReminders/LocationManager.swift, LocationBasedReminders/MainView.swift.

Architecture takeaways

  • LocationBasedRemindersApp is the main source-visible entry or composition anchor for this sample.
  • Framework work reaches SwiftUI, EventKit, MapKit, CoreLocation through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
  • Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
  • Access-control conclusions separate verified language visibility from the likely design rationale.
  • The source does not justify labeling the design protocol-oriented.

Source map

Source file Relevant symbols
LocationBasedReminders/LocationBasedRemindersApp.swift LocationBasedRemindersApp
LocationBasedReminders/ReminderStore.swift ReminderStoreError, ReminderStore
LocationBasedReminders/ReminderStoreManager.swift ReminderStoreManagerError, ReminderStoreManager
LocationBasedReminders/ContentView.swift ContentView
LocationBasedReminders/LocationManager.swift LocationManager
LocationBasedReminders/MainView.swift MainView
LocationBasedReminders/MapView.swift MapView
LocationBasedReminders/SourceModel.swift SourceModel
LocationBasedReminders/WelcomeView.swift WelcomeView
LocationBasedReminders/MapAnnotation.swift MapAnnotation, Coordinates