Radya Labs Objective-C Coding Style

Radya Labs Objective-C Coding Style

Introduction

Here are some of the documents from Apple that informed the style guide:

• The Objective-C Programming Language
• Cocoa Fundamentals Guide
• Coding Guidelines for Cocoa
• iOS App Programming Guide

Dot & Bracket Notation Syntax

Dot notation should be used for accessing properties only. Bracket notation is used for mutating properties and other instances.

Dot notation

CGFloat heightOfView = self.view.frame.size.height;
Person *person = self.company.person;

Bracket notation

[self.view setBackgroundColor:[UIColor redColor]];
[self.person setFirstName:@"Johnny"];

Variables

Variables names must be named as clear and descriptively as possible.

Single letter variables name should be avoided except in for() loops.

Asterisks indicating pointers belong with the variable, e.g., NSString *text not NSString* text or NSString * text, except in the case of constants.

Property definitions should be used in place of naked instance variables whenever possible. Direct instance variable access should be avoided except in initializer methods (init, initWithCoder:, etc…), dealloc methods and within custom setters and getters. For more information on using Accessor Methods in Initializer Methods and dealloc, see here.

For example:

@interface Person : NSObject

@property (strong, nonatomic) NSString *firstName;
@property (strong, nonatomic) NSString *lastName;

@end

Not

@interface Person : NSObject {
	NSString *firstName;
	NSString *lastName;
}

CGFloat and NSInteger

Always use CGFloat instead of float or double

and NSInteger instead of int

Constants

Constants should be declared as static constants and not #define unless explicitly being used as a macro

Always use 'k' before the constants name.

For example:

static const NSString *kCompanyName = @"Radya Labs";
static const CGFloat kHeaderHeight = 44.0f;

Not:

#define COMPANY_NAME @"Radya Labs"
#define HEADER_HEIGHT 44

Braces {...}

Put open brace { in line with method invocations. Give new line before close brace }

For example:

- (void)fetchDataFromURL:(NSURL *)url {
  ...
}

Not:

- (void)fetchDataFromURL:(NSURL *)url
{
  ...
}

Booleans

Since nil resolves to NO it is unnecessary to compare it in conditions. Never compare something directly to YES, because YES is defined to 1 and a BOOL can be up to 8 bits.

This allows for more consistency across files and greater visual clarity.

For example:

if (!someObject) {
}

Not:

if (someObject == nil) {
}

---

For a BOOL, here are two examples:

if (isAwesome)
if (![someObject boolValue])

Not:

if ([someObject boolValue] == NO)
if (isAwesome == YES) // Never do this.

---

If the name of a BOOL property is expressed as an adjective, the property can omit the “is” prefix but specifies the conventional name for the get accessor, for example:

@property (assign, getter=isEditable) BOOL editable;

pragma mark

#pragma mark directives show up in XCode in the menus for direct access to methods. They have no impact on the program at all. #pragma mark should be used to organize the code.

For example:

@implementation ViewController

#pragma mark - Designated initializer
- (id)init {
  ...
}

#pragma mark - UIViewController

- (void)viewDidLoad {
  ...
}

- (void)viewDidAppear:(BOOL)animated {
  ...
}

#pragma mark - IBAction
- (IBAction)cancel:(id)sender {
  ...
}

#pragma mark - UITableViewDataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
  ...
}

#pragma mark - UITableViewDelegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
  ...
}

NSUserDefaults and NSNotificationCenter key/post naming

Use prefix UserDef. for NSUserDefaults key.

Use prefix Notif. for NSNotificationCenter name.

For example:

[[NSUserDefaults standardUserDefaults] setObject:@"RadyaLabs" forKey:@"UserDef.COMPANY_NAME"];
[[NSNotificationCenter defaultCenter] postNotificationName:@"Notif.STOP_PLAYING_MOVIE" object:nil];