iOS Auto-adjusting autolayout snippet with some tricks

NSObject+UTFrameworkProtected.h

//
//  NSObject+UTFrameworkProtected.h
//  UTFramework
//
//  Created by Juyoung Lee on 2014. 1. 2..
//  Copyright (c) 2014년 Juyoung.me. All rights reserved.
//

#import <Foundation/Foundation.h>
// NSObject내에 저장된 callback을 실행시키는 핼퍼
static char* kUTFrameworkBlockKey = "kUTFrameworkBlockKey";
@interface NSObject (UTFrameworkProtected)
- (void)_invokeBlock:(id)sender;
@end

NSObject+UTFrameworkProtected.m

//
//  NSObject+UTFrameworkProtected.m
//  UTFramework
//
//  Created by Juyoung Lee on 2014. 1. 2..
//  Copyright (c) 2014년 Juyoung.me. All rights reserved.
//

#import "NSObject+UTFrameworkProtected.h"
#import "NSObject+UTFramework.h"

@implementation NSObject (UTFrameworkProtected)

- (void)_invokeBlock:(id)sender {
    UTActionBlock block = [self associatedValueForKey:kUTFrameworkBlockKey];
    if (block)
        block(sender);
}
@end

AutoScaleViewController.h

//
//  AutoScaleViewController.h
//
//
//  Created by Lee, Juyoung on 2015. 7. 5..
//  Copyright (c) 2015년 Juyoung. All rights reserved.
//

#import <UIKit/UIKit.h>

// localized string을 런타임시 컨트롤하기 위한 최상위 뷰컨트롤러
@interface AutoScaleViewController : UIViewController
- (CGSize)originalSize;
- (CGSize)currentSize;
@end

AutoScaleViewController.m

//
//  AutoScaleViewController.m
//
//
//  Created by Lee, Juyoung on 2015. 7. 5..
//  Copyright (c) 2015년 Juyoung. All rights reserved.
//

#import "AutoScaleViewController.h"
#import "UIVIew+SmartLayout.h"

@interface AutoScaleViewController ()
@end

@implementation AutoScaleViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self updateViewConstraintsForView:self.view];
    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    [self.view doSmartLayout:[self originalSize] toSize:[self currentSize]];
}
/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

- (void)updateViewConstraintsForView:(UIView *)view{
    CGSize original = [self originalSize];
    CGSize current = [self currentSize];
//    NSLog(@"%@ => %@", NSStringFromCGSize(original), NSStringFromCGSize(current));
    NSMutableArray *newConstraints = [NSMutableArray array];
    for(NSLayoutConstraint *constraint in view.constraints){
//        NSLog(@"%@\n %d %d \n%@\n %d %f %f", constraint.firstItem, constraint.firstAttribute, constraint.relation, constraint.secondItem, constraint.secondAttribute, constraint.multiplier, constraint.constant);
        if(constraint.multiplier == 1.0f){
//            constraint.firstAttribute = constraint.firstAttribute * (current.width /original.width);
        }
        if( constraint.firstAttribute == NSLayoutAttributeTop
           || constraint.firstAttribute == NSLayoutAttributeBottom
           || constraint.firstAttribute == NSLayoutAttributeHeight
           || constraint.firstAttribute == NSLayoutAttributeCenterY
           || constraint.firstAttribute == NSLayoutAttributeBaseline
           || constraint.firstAttribute == NSLayoutAttributeFirstBaseline
           || constraint.firstAttribute == NSLayoutAttributeTopMargin
           || constraint.firstAttribute == NSLayoutAttributeBottomMargin
           || constraint.firstAttribute == NSLayoutAttributeCenterYWithinMargins
           ){
            if(constraint.firstAttribute == NSLayoutAttributeHeight && [constraint.firstItem isKindOfClass:[UIImageView class]]){
                [newConstraints addObject:[NSLayoutConstraint constraintWithItem:constraint.firstItem attribute:constraint.firstAttribute relatedBy:constraint.relation toItem:constraint.secondItem attribute:constraint.secondAttribute multiplier:constraint.multiplier constant:constraint.constant * current.width / original.width]];
            }
            else{
                [newConstraints addObject:[NSLayoutConstraint constraintWithItem:constraint.firstItem attribute:constraint.firstAttribute relatedBy:constraint.relation toItem:constraint.secondItem attribute:constraint.secondAttribute multiplier:constraint.multiplier constant:constraint.constant * current.height / original.height]];
            }
        }
        else if(constraint.firstAttribute == NSLayoutAttributeLeft
                || constraint.firstAttribute == NSLayoutAttributeRight
                || constraint.firstAttribute == NSLayoutAttributeWidth
                || constraint.firstAttribute == NSLayoutAttributeCenterX
                || constraint.firstAttribute == NSLayoutAttributeLeftMargin
                || constraint.firstAttribute == NSLayoutAttributeRightMargin
                || constraint.firstAttribute == NSLayoutAttributeCenterXWithinMargins
                ){
            [newConstraints addObject:[NSLayoutConstraint constraintWithItem:constraint.firstItem attribute:constraint.firstAttribute relatedBy:constraint.relation toItem:constraint.secondItem attribute:constraint.secondAttribute multiplier:constraint.multiplier constant:constraint.constant * current.width / original.width]];
        }
        else{
            [newConstraints addObject:constraint];
        }
    }
    [view removeConstraints:view.constraints];
    [view addConstraints:newConstraints];
    for(UIView *subview in view.subviews){
        [self updateViewConstraintsForView:subview];
    }
}

- (CGSize)originalSize{
    return CGSizeMake(320, 568);
}

- (CGSize)currentSize{
    return self.view.frame.size;
}
@end

NSObject+UTFramework.h

//
//  NSObject+UTFramework.h
//  UTFramework
//
//  Created by Juyoung Lee on 2014. 1. 2..
//  Copyright (c) 2014년 Juyoung.me. All rights reserved.
//

#import <Foundation/Foundation.h>

// Object에 데이터를 저장하기 위한 helper NSObject를 상속받은 모든 객체는 이 함수를 통해 객체내부에 데이터 저장이 가능하다.
// 보통 callback등을 저장하는데 사용되거나, static 변수등으로 처리하기 까다로울때 사용된다.
typedef void (^UTActionBlock)(id sender);

@interface NSObject (UTFramework)

- (void)retainAssociateValue:(id)value withKey:(const char *)key;
- (void)copyAssociateValue:(id)value withKey:(const char *)key;
- (void)assignAssociateValue:(id)value withKey:(const char *)key;
- (id)associatedValueForKey:(const char *)key;
- (void)removeAllAssociatedObjects;

+ (void)retainAssociateValue:(id)value withKey:(const char *)key;
+ (void)copyAssociateValue:(id)value withKey:(const char *)key;
+ (void)assignAssociateValue:(id)value withKey:(const char *)key;
+ (id)associatedValueForKey:(const char *)key;
+ (void)removeAllAssociatedObjects;
@end

NSObject+UTFramework.m

//
//  NSObject+UTFramework.m
//  UTFramework
//
//  Created by Juyoung Lee on 2014. 1. 2..
//  Copyright (c) 2014년 Juyoung.me. All rights reserved.
//

#import "NSObject+UTFramework.h"
#import <objc/runtime.h>

@implementation NSObject (UTFramework)

- (void)retainAssociateValue:(id)value withKey:(const char *)key {
    objc_setAssociatedObject(self, key, value, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (void)copyAssociateValue:(id)value withKey:(const char *)key {
    objc_setAssociatedObject(self, key, value, OBJC_ASSOCIATION_COPY_NONATOMIC);
}

- (void)assignAssociateValue:(id)value withKey:(const char *)key {
    objc_setAssociatedObject(self, key, value, OBJC_ASSOCIATION_ASSIGN);
}

- (id)associatedValueForKey:(const char *)key {
    return objc_getAssociatedObject(self, key);
}

- (void)removeAllAssociatedObjects {
    objc_removeAssociatedObjects(self);
}

+ (void)retainAssociateValue:(id)value withKey:(const char *)key {
    objc_setAssociatedObject(self, key, value, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

+ (void)copyAssociateValue:(id)value withKey:(const char *)key {
    objc_setAssociatedObject(self, key, value, OBJC_ASSOCIATION_COPY_NONATOMIC);
}

+ (void)assignAssociateValue:(id)value withKey:(const char *)key {
    objc_setAssociatedObject(self, key, value, OBJC_ASSOCIATION_ASSIGN);
}

+ (id)associatedValueForKey:(const char *)key {
    return objc_getAssociatedObject(self, key);
}

+ (void)removeAllAssociatedObjects {
    objc_removeAssociatedObjects(self);
}

@end

UIView+SmartLayout.h

//
//  UIView+SmartLayout.h
//  UTFramework
//
//  Created by Juyoung Lee on 2014. 1. 2..
//  Copyright (c) 2014년 Juyoung.me. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIView (SmartLayout)

- (void)doSmartLayout:(CGSize)originalSize toSize:(CGSize)toSize;
- (void)smartLayout:(CGSize)originalSize toSize:(CGSize)toSize;
@end

UIView+SmartLayout.m

//
//  UIView+SmartLayout.m
//  UTFramework
//
//  Created by Juyoung Lee on 2014. 1. 2..
//  Copyright (c) 2014년 Juyoung.me. All rights reserved.
//

#import "UIVIew+SmartLayout.h"
#import "NSObject+UTFramework.h"
#import "UILabel+SmartLayout.h"

@implementation UIView (SmartLayout)

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code
}
*/

- (void)smartLayout:(CGSize)originalSize toSize:(CGSize)toSize{
    [self doSmartLayout:originalSize toSize:toSize];
}

- (void)doSmartLayout:(CGSize)originalSize toSize:(CGSize)toSize{
    static char *smartLayoutChar = "kSmartLayoutKey";
    NSNumber *val = [self associatedValueForKey:smartLayoutChar];
    if(![val boolValue]){
        [self copyAssociateValue:@YES withKey:smartLayoutChar];
        [self smartLayout:originalSize toSize:toSize];
        for(UIView *view in self.subviews){
            [view smartLayout:originalSize toSize:toSize];
        }
    }
}
@end