Present/dismiss a custom full screen modal alert #modals #ios #views #intermediate

custom_fullscreen_modals.m

static const CGFloat _BG_ALPHA = 0.3;
static const NSTimeInterval _ANIM_TIME = 0.3;

static UIWindow *_mainWindow;
static UIWindow *_alertWindow;

- (void)showExplainerScreen
{
    _mainWindow = [[UIApplication sharedApplication] keyWindow];
    
    // WINDOW
    _alertWindow = [[UIWindow alloc] initWithFrame:_mainWindow.frame];
    _alertWindow.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    _alertWindow.opaque = NO;
    _alertWindow.windowLevel = UIWindowLevelAlert;
    
    // VC
    UIViewController *vc = [[UIViewController alloc] init];
    _alertWindow.rootViewController = vc;
    // If you want statusBar hidden you need a custom VC
    
    // VIEW
    // bg
    vc.view.backgroundColor = UIColor.blackColor;
    vc.view.frame = _alertWindow.frame;
    
    // your custom views
    // ...
    
    // PRESENT
    vc.view.alpha = 0;
    [_alertWindow makeKeyAndVisible];
    [UIView
     animateWithDuration:_ANIM_TIME
     animations:^{
         vc.view.alpha = _BG_ALPHA;
     }
     completion:^(BOOL finished) {
     }];
    
    // DISMISS ON TOUCH
    UITapGestureRecognizer *gr = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(dismissExplainerScreen)];
    [vc.view addGestureRecognizer:gr];
}

- (void)dismissExplainerScreen
{
    BOOL animated = YES;
    
    void (^cleanup)(void) = ^void(void)
    {
        [_mainWindow makeKeyAndVisible];
        _alertWindow = nil;
    };
    
    if (!animated)
    {
        cleanup();
    }
    else
    {
        [UIView
         animateWithDuration:_ANIM_TIME
         animations:^{
             _alertWindow.rootViewController.view.alpha = 0;
         }
         completion:^(BOOL finished) {
             cleanup();
         }];
    }
}