martinhering

- (void) setScrollView:(UIScrollView*)scrollView contentInsets:(UIEdgeInsets)edgeInsets byAdjustingForStandardBars:(BOOL)adjustStandardBars
{
    if (adjustStandardBars)
    {
        UINavigationController* navController = self.navigationController;
        
        if (navController)
        {
            CGRect navBarFrame = self.navigationController.navigationBar.frame;
            edgeInsets.top += CGRectGetMinY(navBarFrame);           // statusbar

nicklockwood

Suppose we want to add support for a new iOS 8 API in our framework that replaces an older iOS 7 API. There are a few problems we might face:

1. The new API will crash if we call it on iOS 7
2. The new API won't compile if we build it using the iOS 7 SDK
3. The old API will raise a deprecation warning if built with a deployment target of iOS 8 and up

These three problems require three different technical solutions:

1. We can avoid calling the new API on an old OS version by using runtime detection (e.g. respondsToSelector:)
2. We can avoid compiling new APIs on old SDKs using the __IPHONE_OS_VERSION_MAX_ALLOWED macro

interstateone

#import <Foundation/Foundation.h>


#define apply(block, a) (^{ \
    switch (a.count) { \
        case 1: return block(a[0], nil); \
        case 2: return block(a[0], a[1], nil); \
        case 3: return block(a[0], a[1], a[2], nil); \
        case 4: return block(a[0], a[1], a[2], a[3], nil); \
        case 5: return block(a[0], a[1], a[2], a[3], a[4], nil); \

kyleve

/**
 Provides the ability to verify key paths at compile time.
 
 If "keyPath" does not exist, a compile-time error will be generated.
 
 Example:
    // Verifies "isFinished" exists on "operation".
    NSString *key = SQKeyPath(operation, isFinished);
 
    // Verifies "isFinished" exists on self.

jazzychad

#import "SPVMainViewController.h"

@implementation SPVMainViewController
{
    UIView *_weightView;
    UIPanGestureRecognizer *_recog;
}

- (void)viewDidLoad
{

jaybaird

#import <Foundation/Foundation.h>

@interface Node : NSObject
@property (nonatomic) NSInteger identifier;
@property (nonatomic, copy) NSString *value;
+ (Node *)nodeWithIdentifier:(NSInteger)identifier value:(NSString *)value;
@end

@implementation Node
+ (Node *)nodeWithIdentifier:(NSInteger)identifier value:(NSString *)value {

krzysztofzablocki

typedef NS_ENUM(NSInteger, kErrorCode) {
  kErrorCodeInternal = 431432,
};
 
//! generate error and log it.
extern NSError *pixle_NSErrorMake(NSString *message, NSUInteger code, NSDictionary *aUserInfo, SEL selector);
 
#define AssertTrueOrReturnBlock(condition, block) do{ NSAssert((condition), @"Invalid condition not satisfying: %s", #condition);\
    if(!(condition)) { block(pixle_NSErrorMake([NSString stringWithFormat:@"Invalid condition not satisfying: %s", #condition], kErrorCodeInternal, nil, _cmd)); return;} }while(0)
 

JaviSoto

#define MSDesignatedInitializer(__SEL__) __attribute__((unavailable("Invoke the designated initializer `" # __SEL__ "` instead.")))

// Sample usage:

- (instancetype)initWithObject:(id)object;
- (instancetype)init MSDesignatedInitializer(initWithObject:); // <- This even gets auto-complete.

// Now calling init on this class would throw a warning.

steipete

// Taken from the commercial iOS PDF framework http://pspdfkit.com.
// Copyright (c) 2014 Peter Steinberger, PSPDFKit GmbH. All rights reserved.
// Licensed under MIT (http://opensource.org/licenses/MIT)
//
// You should only use this in debug builds. It doesn't use private API, but I wouldn't ship it.

// PLEASE DUPE rdar://27192338 (https://openradar.appspot.com/27192338) if you would like to see this in UIKit.

#import <objc/runtime.h>
#import <objc/message.h>

steipete

// Defines a yet undocumented method to add a warning if super isn't called.
#ifndef NS_REQUIRES_SUPER
#if __has_attribute(objc_requires_super)
#define NS_REQUIRES_SUPER __attribute((objc_requires_super))
#else
#define NS_REQUIRES_SUPER
#endif
#endif

@interface UIViewController (SubclassingWarnings)