LayoutWrapperView.h

#import <UIKit/UIKit.h>


@interface LayoutWrapperView : UIView

@property (nonatomic, readonly) UIView *view;

@property (nonatomic, assign) UIEdgeInsets insets;

@property (nonatomic, assign) BOOL collapsesIfViewIsNotVisible;

- (id)initWithView:(UIView *)view;
- (id)initWithView:(UIView *)view insets:(UIEdgeInsets)insets;

@end

LayoutWrapperView.m

#import "LayoutWrapperView.h"
#import "Masonry.h"


static char kViewVisibilityKVOContext;

@interface LayoutWrapperView ()

@property (nonatomic, strong) NSArray *constraints;

@end


@implementation LayoutWrapperView

#pragma mark - Init

- (id)initWithFrame:(CGRect)frame {
    return [self initWithView:nil];
}

- (id)initWithCoder:(NSCoder *)aDecoder {
    return [self initWithView:nil];
}

- (id)initWithView:(UIView *)view {
    return [self initWithView:view insets:UIEdgeInsetsZero];
}

- (id)initWithView:(UIView *)view insets:(UIEdgeInsets)insets {
    NSParameterAssert(view != nil);
    
    self = [super initWithFrame:CGRectZero];
    if (!self) return nil;
    
    self.hidden = YES;
    self.userInteractionEnabled = NO;
    
    _view = view;
    _view.translatesAutoresizingMaskIntoConstraints = NO;
    [_view addObserver:self forKeyPath:@"alpha" options:0 context:&kViewVisibilityKVOContext];
    [_view addObserver:self forKeyPath:@"hidden" options:0 context:&kViewVisibilityKVOContext];
    
    _insets = insets;
    
    return self;
}

#pragma mark - Dealloc

- (void)dealloc {
    [_view removeObserver:self forKeyPath:@"alpha" context:&kViewVisibilityKVOContext];
    [_view removeObserver:self forKeyPath:@"hidden" context:&kViewVisibilityKVOContext];
}

#pragma mark - Properties

- (void)setInsets:(UIEdgeInsets)insets {
    if (!UIEdgeInsetsEqualToEdgeInsets(_insets, insets)) {
        _insets = insets;
        [self setNeedsUpdateConstraints];
    }
}

- (void)setCollapsesIfViewIsNotVisible:(BOOL)collapsesIfViewIsNotVisible {
    if (_collapsesIfViewIsNotVisible != collapsesIfViewIsNotVisible) {
        _collapsesIfViewIsNotVisible = collapsesIfViewIsNotVisible;
        [self setNeedsUpdateConstraints];
    }
}

#pragma mark - KVO

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    if (context != &kViewVisibilityKVOContext) {
        return [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
    }
    
    if (self.collapsesIfViewIsNotVisible) {
        [self setNeedsUpdateConstraints];
    }
}

#pragma mark - UIView

- (void)updateConstraints {
    for (MASConstraint *constraint in self.constraints) {
        [constraint uninstall];
    }
    
    self.constraints = [self mas_makeConstraints:^(MASConstraintMaker *make) {
        if ([self shouldCollapse]) {
            make.center.equalTo(self.view);
        } else {
            make.edges.equalTo(self.view).with.insets(UIEdgeInsetsMake(-self.insets.top, -self.insets.left, -self.insets.bottom, -self.insets.right));
        }
    }];
    
    [super updateConstraints];
}

#pragma mark - Private

- (BOOL)shouldCollapse {
    return self.collapsesIfViewIsNotVisible && (self.view.hidden || self.view.alpha <= 0.01);
}

@end