Размытие во весь экран

Я думаю, вы можете использовать FXBlurView. Это полезная библиотека. После импорта этой библиотеки вы можете добавить новый вид (или вы можете создать его динамически). Тип класса Viewcontroller должен быть FXBlurView. Вы можете найти небольшой пример ниже.

 @property (nonatomic, weak) IBOutlet FXBlurView *blurView;
 ...
 self.blurView.blurRadius = 40; // you can set 0 to 100

Изменить:

Если вы не хотите использовать библиотеку, вам нужно создать собственное размытие фона. Я скопировал ваш код и отредактировал его. вы можете найти его ниже.

BlurBG.h:

#import <UIKit/UIKit.h>

@interface BlurBG : UIViewController
- (void)showAlert:(UIViewController *)vc;
- (void) ProgressUpdate ;
@end

BlurBG.m:

#import "BlurBG.h"
#import "UIImage+ImageEffects.h"
#import <AVFoundation/AVFoundation.h>

#define UIColorFromRGB(rgbValue) [UIColor \
colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 \
green:((float)((rgbValue & 0xFF00) >> 8))/255.0 \
blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0]

#define SYSTEM_VERSION_EQUAL_TO(v)                  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedSame)
#define SYSTEM_VERSION_GREATER_THAN(v)              ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedDescending)
#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN(v)                 ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN_OR_EQUAL_TO(v)     ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedDescending)

#define KEYBOARD_HEIGHT 80
#define PREDICTION_BAR_HEIGHT 40

@interface BlurBG ()
@property (nonatomic, strong) UIImageView *backgroundView;
@property (nonatomic, strong) UIView *contentView;
@property (nonatomic, strong) UIButton *OkBtn;
@property UIProgressView *prog;
@property (nonatomic) CGFloat backgroundOpacity;
@property UILabel *labelTitle;
@property UITextView *viewText;
@end

@implementation BlurBG

CGFloat kWindowWidth;
CGFloat kWindowHeight;
CGFloat kTextHeight;
CGFloat kSubTitleHeight;

#pragma mark - Initialization

- (id)initWithCoder:(NSCoder *)aDecoder
{
    @throw [NSException exceptionWithName:NSInternalInconsistencyException
                               reason:@"NSCoding not supported"
                             userInfo:nil];
}

-(instancetype) init{
    self = [super init];
    if (self)
    {
        kWindowWidth = [UIScreen mainScreen].bounds.size.width-50;
        kWindowHeight = ([UIScreen mainScreen].bounds.size.height/5);

        _OkBtn = [[UIButton alloc] initWithFrame:CGRectMake(kWindowWidth-25,5,20,20)];
        _OkBtn.backgroundColor=[UIColor grayColor];
        [_OkBtn setTitle:@"X" forState:UIControlStateNormal];
        _OkBtn.layer.cornerRadius = 1;
        _OkBtn.clipsToBounds = YES;
        [_OkBtn addTarget:self action:@selector(fadeOut) forControlEvents:UIControlEventTouchUpInside];

        _prog = [[UIProgressView alloc] initWithProgressViewStyle:UIProgressViewStyleDefault];

        _labelTitle = [[UILabel alloc] init];
        _viewText = [[UITextView alloc] init];
        _contentView = [[UIView alloc] init];

        [self.view addSubview:_contentView];

        [_contentView addSubview:_labelTitle];
        [_contentView addSubview:_viewText];
        [_contentView addSubview:_prog];
        [_contentView addSubview:_OkBtn];

    // Content View
        _contentView.layer.cornerRadius = 5.0f;
        _contentView.layer.masksToBounds = YES;
        _contentView.layer.borderWidth = 0.5f;

        _labelTitle.numberOfLines = 1;
        _labelTitle.textAlignment = NSTextAlignmentCenter;
        _labelTitle.font = [UIFont fontWithName:@"HelveticaNeue" size:20.0f];

    // View text
        _viewText.editable = NO;
        _viewText.allowsEditingTextAttributes = YES;
        _viewText.textAlignment = NSTextAlignmentCenter;
        _viewText.font = [UIFont fontWithName:@"HelveticaNeue" size:14.0f];

        _backgroundView = [[UIImageView alloc]initWithFrame:[UIScreen mainScreen].bounds];
        _backgroundView.userInteractionEnabled = YES;

        _contentView.backgroundColor = [UIColor whiteColor];
        _labelTitle.textColor = UIColorFromRGB(0x4D4D4D);
        _viewText.textColor = UIColorFromRGB(0x4D4D4D);
        _contentView.layer.borderColor = UIColorFromRGB(0xCCCCCC).CGColor;

    }
    return self;
}

-(void) ShowTitle:(UIViewController *)vc{
    UIWindow *window = [[UIApplication sharedApplication] keyWindow];

    self.view.alpha = 0;

    [self makeBlurBackground];
    _backgroundView.frame = vc.view.bounds;

    _labelTitle.text = @"Title";
    _viewText.text = @"Description..";

    [window addSubview:_backgroundView];
    [window addSubview:self.view];
    [vc addChildViewController:self];

    [self fadeIn];
}

- (void)showAlert:(UIViewController *)vc {
    [self ShowTitle:vc];
}

-(void)viewWillLayoutSubviews
{
    [super viewWillLayoutSubviews];

    CGSize sz = [UIScreen mainScreen].bounds.size;

    if (SYSTEM_VERSION_LESS_THAN(@"8.0"))
    {
        if UIInterfaceOrientationIsLandscape([[UIApplication sharedApplication] statusBarOrientation])
        {
            CGSize ssz = sz;
            sz = CGSizeMake(ssz.height, ssz.width);
        }
    }

    CGRect newFrame = self.backgroundView.frame;
    newFrame.size = sz;
    self.backgroundView.frame = newFrame;

    CGRect r;
    if (self.view.superview != nil)
    {
        r = CGRectMake((sz.width-kWindowWidth)/2, (sz.height-kWindowHeight)/2, kWindowWidth, kWindowHeight/2);
    }
    else
    {
        r = CGRectMake((sz.width-kWindowWidth)/2, -kWindowHeight, kWindowWidth, kWindowHeight);
    }

    self.view.frame = r;

    _contentView.frame = CGRectMake(0,0, kWindowWidth, kWindowHeight);
    _labelTitle.frame = CGRectMake((kWindowWidth-(kWindowWidth-10))/2, 5, kWindowWidth-10,28);
    _viewText.frame = CGRectMake((kWindowWidth-(kWindowWidth-10))/2, 8+(_labelTitle.frame.size.height), kWindowWidth-10,28);
    _prog.frame = CGRectMake((kWindowWidth-(kWindowWidth-10))/2, 65, kWindowWidth-10,28);
}

- (void)fadeIn
{
    self.backgroundView.alpha = 0.0f;
    self.view.alpha = 0.0f;

    [UIView animateWithDuration:0.3f
                      delay:0.0f
                    options:UIViewAnimationOptionCurveEaseIn
                 animations:^{
                     self.backgroundView.alpha = _backgroundOpacity;
                     self.view.alpha = 1.0f;
                 }
                 completion:^(BOOL completed){


    [self performSelectorOnMainThread:@selector(ProgressUpdate) withObject:nil waitUntilDone:YES];
                     }];
    }

    - (void)fadeOut
    {
    [UIView animateWithDuration:0.3f animations:^{
        self.backgroundView.alpha = 0.0f;
        self.view.alpha = 0.0f;
    } completion:^(BOOL completed) {
        [self.backgroundView removeFromSuperview];
        [self.view removeFromSuperview];
        [self removeFromParentViewController];
    }];
}

- (void)makeBlurBackground
{
    UIImage *image = [UIImage convertViewToImage];
    UIImage *blurSnapshotImage = [image applyBlurWithRadius:5.0f
                                                  tintColor:[UIColor colorWithWhite:0.2f
                                                                              alpha:0.7f]
                                      saturationDeltaFactor:1.8f
                                                  maskImage:nil];

    _backgroundView.image = blurSnapshotImage;
    _backgroundView.alpha = 0.0f;
    _backgroundOpacity = 1.0f;
}

-(void) ProgressUpdate {
    __weak typeof(self) weakSelf = self;
    dispatch_async(dispatch_get_main_queue(), ^{
        __strong typeof(weakSelf) strongSelf = weakSelf;
        if (strongSelf) {
            for (int i=0; i<100; i++) {
                [NSThread sleepForTimeInterval:0.1];
                float currentProgress = _prog.progress;
                NSLog(@"%f",currentProgress);
                [strongSelf.prog setProgress:currentProgress+0.01 animated:YES];
            };
        }
    });
}

@end

Вызов BlurBG:

BlurBG *bg = [[BlurBG alloc]init];
[bg showAlert:self];
[bg ProgressUpdate];

Apple предоставила нам замечательный ресурс для воспроизведения эффекта размытия. Посмотрите UIBlurEffect

typedef enum {
UIBlurEffectStyleExtraLight,
UIBlurEffectStyleLight,
UIBlurEffectStyleDark 
} UIBlurEffectStyle;