To show views on top of uiview controller easily

PopupView.m

//
//  PopupView.m
//  Modeling
//
//  Created by Heechul on 10/26/15.
//  Copyright © 2015 min. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface PopupView : UIView

+ (void)presentView:(UIView *)view;
@end

<!--#import "PopupView.h"-->

@interface PopupView ()
@property (nonatomic, strong) UIControl *dimmedView;
@end

@implementation PopupView

+ (void)presentView:(UIView *)view
{
    UIWindow *window = [UIApplication sharedApplication].keyWindow;

    PopupView *popupV = [[PopupView alloc] init];

    [window addSubview:popupV];

    [popupV present];

    [popupV addMainView:view];
}

- (id)init
{
    self = [super init];
    if (self) {
        [self setup];
    }
    return self;
}

- (void)present
{
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.3];
    _dimmedView.alpha = 1;
    [UIView commitAnimations];
}

- (void)addMainView:(UIView *)view
{
    UIView *backgroundView = ({
        UIView *v = [[UIView alloc] init];
        v.backgroundColor = [UIColor whiteColor];
        v.layer.cornerRadius = 10;
        v.layer.masksToBounds = YES;
        v;
    });

    [self addSubview:backgroundView];

    [backgroundView addSubview:view];

    CGSize size = view.frame.size;

    backgroundView.translatesAutoresizingMaskIntoConstraints = NO;
    view.translatesAutoresizingMaskIntoConstraints = NO;

    [self addConstraint:[NSLayoutConstraint constraintWithItem:_dimmedView attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:backgroundView attribute:NSLayoutAttributeCenterX multiplier:1 constant:0]];

    [self addConstraint:[NSLayoutConstraint constraintWithItem:_dimmedView attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:backgroundView attribute:NSLayoutAttributeCenterY multiplier:1 constant:0]];

    NSDictionary *views = NSDictionaryOfVariableBindings(backgroundView, view);

    NSDictionary *metrics = @{
                              @"width":@(size.width),
                              @"height":@(size.height)
                              };

    [self addConstraints:[NSLayoutConstraint
                          constraintsWithVisualFormat:
                          @"H:[backgroundView(width)]"
                          options:kNilOptions
                          metrics:metrics
                          views:views]];

    [self addConstraints:[NSLayoutConstraint
                          constraintsWithVisualFormat:
                          @"V:[backgroundView(height)]"
                          options:kNilOptions
                          metrics:metrics
                          views:views]];

    [self addConstraints:[NSLayoutConstraint
                          constraintsWithVisualFormat:
                          @"H:|[view]|"
                          options:kNilOptions
                          metrics:metrics
                          views:views]];

    [self addConstraints:[NSLayoutConstraint
                          constraintsWithVisualFormat:
                          @"V:|[view]|"
                          options:kNilOptions
                          metrics:metrics
                          views:views]];

    view.alpha = 0;
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.3];
    view.alpha = 1;
    [UIView commitAnimations];

}

- (void)setup
{
    UIWindow *window = [UIApplication sharedApplication].keyWindow;

    [self setFrame:window.bounds];
    _dimmedView = [[UIControl alloc] init];
    _dimmedView.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.3];
    [_dimmedView addTarget:self action:@selector(tapped) forControlEvents:UIControlEventTouchUpInside];
    _dimmedView.alpha = 0;

    [self addSubview:_dimmedView];


    _dimmedView.translatesAutoresizingMaskIntoConstraints = NO;

    UIView *superV = self;

    NSDictionary *views = NSDictionaryOfVariableBindings(_dimmedView, superV);

    [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[_dimmedView]|" options:kNilOptions metrics:@{} views:views]];

    [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[_dimmedView]|" options:kNilOptions metrics:@{} views:views]];
}

- (void)tapped
{
    [self removeFromSuperview];
}


@end