Introduction

Good Objective-C and Cocoa code is less about memorizing stylistic trivia and more about writing code that fits the framework's lifecycle, ownership, and delegation model. The most reliable practices are the ones that keep object initialization explicit, UI work on the main thread, and APIs small enough to read without reverse-engineering intent.

Start With Clear Object Ownership

Under ARC, you rarely manage retain and release manually, but ownership rules still matter. Use strong properties for owned objects and weak references for delegates or back-references that should not create retain cycles.

1@interface ProfileViewController : UIViewController
2
3@property (nonatomic, strong) NSString *username;
4@property (nonatomic, weak) id<UITableViewDelegate> delegate;
5
6@end

The point is not just syntax. It is making ownership visible in the API. A reader should be able to tell which objects this class keeps alive and which ones it merely references.

Make Initialization Explicit

Objective-C code becomes fragile quickly when initialization rules are vague. A designated initializer keeps object creation predictable and avoids half-configured instances.

1@interface User : NSObject
2
3@property (nonatomic, copy, readonly) NSString *name;
4
5- (instancetype)initWithName:(NSString *)name NS_DESIGNATED_INITIALIZER;
6- (instancetype)init NS_UNAVAILABLE;
7
8@end
9
10@implementation User
11
12- (instancetype)initWithName:(NSString *)name {
13    self = [super init];
14    if (self) {
15        _name = [name copy];
16    }
17    return self;
18}
19
20@end

This makes it clear which values are required and prevents callers from creating invalid objects accidentally.

Keep UI Work on the Main Thread

Cocoa UI frameworks expect view updates on the main thread. Background work is fine, but state changes that affect views should return to the main queue explicitly.

1dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INITIATED, 0), ^{
2    NSString *result = @"Loaded";
3
4    dispatch_async(dispatch_get_main_queue(), ^{
5        self.titleLabel.stringValue = result;
6    });
7});

This is a basic habit, but it prevents many subtle bugs and intermittent crashes in AppKit and UIKit code.

Prefer Small, Focused Classes

Massive view controllers are a common smell in Cocoa codebases. If a controller is handling layout, networking, parsing, persistence, and formatting, it becomes difficult to test and risky to change.

Push responsibilities into focused collaborators when possible:

• model or service objects for data retrieval,
• formatters for presentation logic,
• separate datasource or delegate helpers for table logic.

Objective-C becomes much easier to maintain when class names correspond to one clear responsibility instead of one controller owning the entire screen.

Use Cocoa Conventions Instead of Fighting Them

Framework conventions exist for a reason. Prefer delegation, target-action, notifications, and data sources where those patterns naturally fit.

A target-action example:

[self.saveButton setTarget:self];
[self.saveButton setAction:@selector(saveDocument:)];

And the action method:

- (IBAction)saveDocument:(id)sender {
    NSLog(@"Saving document");
}

Using familiar Cocoa patterns makes the code more readable to the next developer because the behavior matches what the framework expects.

Be Careful With Nullability and API Clarity

Modern Objective-C benefits from nullability annotations and explicit API contracts. They improve Swift interoperability and make intent clearer even for Objective-C callers.

- (nullable NSString *)displayNameForUserID:(nonnull NSString *)userID;

Likewise, property attributes such as copy for strings and blocks are not decoration. They encode semantics that prevent bugs.

Use method names that read like Cocoa methods. A long but precise selector is usually better than a short ambiguous one.

Common Pitfalls

• Relying on default init even when the object needs required data to be valid.
• Updating UI objects from a background queue.
• Using strong for delegates and creating retain cycles.
• Putting too much unrelated behavior into one controller.
• Ignoring Cocoa naming and lifecycle conventions, which makes the code feel foreign to the framework.

Summary

• Objective-C and Cocoa code is strongest when ownership, initialization, and framework conventions are explicit.
• Use strong and weak references deliberately so object relationships stay clear.
• Define designated initializers for objects with required construction data.
• Keep UI updates on the main thread and move background work off it.
• Favor small, framework-friendly classes over large controllers that mix unrelated responsibilities.