Creating and Customizing the Touch Bar

At a glance

Project structure

Source bundle/
├── Objective-C/
│   └── NSTouchBar Catalog/
│       ├── main.m
│       ├── TestViewControllers/
│       │   ├── VisbilityViewController.m
│       │   └── ButtonViewController.m
│       ├── AppDelegate.h
│       ├── AppDelegate.m
│       ├── BackgroundWindow/
│       │   ├── PhotoManager.h
│       │   ├── BackgroundImagesViewController.m
│       │   └── BackgroundViewController.m
│       └── PrimaryViewController.m
└── Swift/
    └── NSTouchBar Catalog/
        ├── ScrubberViewController.swift
        ├── AppDelegate.swift
        └── VisibilityViewController.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: C/Objective-C header, Objective-C, Swift.
• The verified tree contains 56 project/configuration file(s) and 95 source declaration(s).

Overall architecture

flowchart LR
    Bundle["Sample bundle"]
    V1["Objective-C"]
    V2["Swift"]
    Boundary["Cocoa / Contacts APIs"]
    Bundle --> V1
    V1 --> Boundary
    Bundle --> V2
    V2 --> Boundary

Reference code

Objective-C/NSTouchBar Catalog/main.m:10 — architecture anchor

int main(int argc, const char * argv[])
{
    return NSApplicationMain(argc, argv);
}

Interpretation

The branches represent separate entry-bearing project variants in the downloaded bundle, not runtime calls between those variants. Each branch is intentionally collapsed at the documented framework boundary; the detailed target-local flow remains in the cited files. Ownership is claimed only where the next section cites a stored property or assignment.

Ownership and state

classDiagram
    VisbilityViewController o-- NSTouchBarItem : button1
    PhotoManager o-- NSMutableArray : photos
    PhotoManager o-- BOOL : loadComplete
    PhotoManager o-- id : delegate

Ownership evidence

Objective-C/NSTouchBar Catalog/TestViewControllers/VisbilityViewController.m:23 — stored dependency or nearest verified ownership anchor

@interface VisibilityViewController () <NSTextFieldDelegate>
// ...
@property (weak) IBOutlet NSTouchBarItem *button1;
// ...
@end

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.

Concurrency, scheduling, and thread safety

Evidence limit: actor isolation, async/await, or Task creation does not by itself prove background-thread execution; Sendable conformance alone does not prove thread-safe mutation.

@MainActor/MainActor.run, DispatchQueue.main, and RunLoop.main are reported as distinct isolation, queue, and event-loop mechanisms. A plain Task is kept separate from Task.detached; neither is labeled as a background thread.

Reference code

Swift/NSTouchBar Catalog/CandidateListViewController.swift:103 — representative execution boundary

                        DispatchQueue.main.async {
                            candidates = self.candidates(matching: textField.stringValue)
                        }

State propagation, frameworks, and dependencies

Evidence limit: an import proves a source-level compilation dependency at the cited line; it does not prove runtime use, architectural adoption, or whether a Swift package is a direct application dependency.

receive(on:) describes downstream delivery scheduling, while subscribe(on:) describes upstream subscription/request/cancel scheduling. An import Combine alone establishes neither behavior nor a Store, reducer, Redux, or other application architecture.

Class and protocol design

Objective-C/NSTouchBar Catalog/BackgroundWindow/PhotoManager.h:11 — representative type boundary

@protocol PhotoManagerDelegate;

The source explicitly defines local protocol relationships: BackgroundImagesViewController → PhotoManagerDelegate, ImageScrubberBarItemSample → PhotoManagerDelegate.

Access control

Reference code

Objective-C/NSTouchBar Catalog/BackgroundWindow/BackgroundImagesViewController.m:26 — representative boundary

@interface BackgroundImagesViewController () <  NSTouchBarDelegate,
// ...
@property (nonatomic, weak) IBOutlet NSScrollView *scrollView;
// ...
@end

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

Design patterns

Main application flow

sequenceDiagram
    participant CandidateListViewController
    participant CNContactStore
    participant contactStore
    participant NSAlert
    participant alert
    participant candidateListItem
    CandidateListViewController->>CNContactStore: authorizationStatusForEntityType()
    CandidateListViewController->>CNContactStore: alloc()
    CandidateListViewController->>contactStore: completionHandler
    CandidateListViewController->>CandidateListViewController: searchForCandidatesWithString()
    CandidateListViewController->>CNContactStore: authorizationStatusForEntityType()
    CandidateListViewController->>NSAlert: alloc()
    CandidateListViewController->>alert: runModal()
    CandidateListViewController->>candidateListItem: forSelectedRange()

Reference code

Objective-C/NSTouchBar Catalog/TestViewControllers/CandidateListViewController.m:140 — controlTextDidChange()

@implementation CandidateListViewController
// ...
            [contactStore requestAccessForEntityType:entityType completionHandler:^(BOOL granted, NSError * _Nullable error) {
                if (granted)
                {
                    dispatch_async(dispatch_get_main_queue(), ^{
                        [self searchForCandidatesWithString:textField.stringValue];
                    });
                }
            }];
// ...
@end

Naming conventions

• Types: Controller: BackgroundImagesViewController, BackgroundViewController, ButtonViewController, CandidateListViewController, ColorPickerViewController; Delegate: AppDelegate, PhotoManagerDelegate; Manager: PhotoManager; View: CanvasView, CustomBackgroundView, CustomSelectionBackgroundView, CustomSelectionOverlayView, CustomView.
• Protocols: PhotoManagerDelegate, PhotoManagerDelegate, PhotoManagerDelegate.
• Methods: customizeAction, useBackgroundColorAction, kindAction, modeAction, selectionAction, overlayAction, flowAction, spacingSliderAction.
• Files: Swift/NSTouchBar Catalog/ScrubberViewController.swift, Objective-C/NSTouchBar Catalog/AppDelegate.h, Objective-C/NSTouchBar Catalog/AppDelegate.m, Swift/NSTouchBar Catalog/AppDelegate.swift, Objective-C/NSTouchBar Catalog/BackgroundWindow/PhotoManager.h, Swift/NSTouchBar Catalog/VisibilityViewController.swift.

Architecture takeaways

• main is the main source-visible entry or composition anchor for this sample.
• Framework work reaches Cocoa, Contacts 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.
• Local protocol relationships provide an explicit substitution boundary.

Source map

• Official Apple documentation