Mimicking a notification UIVIew with darkened background - ios

Question

I am interested in creating a pop-up notification view similar to the design patterns seen below, where a UIView pops up and the rest of the screen is darkened, and done without using a new modal view. Since this design pattern is so commonly seen, I was wondering if there is a "tried-and-true" way to doing it (or there a widely used open source framework like AFNetworking for downloading/uploading files and images)?
Thanks.

Answer 1

Here's a good start:
PopupView.h
#import <UIKit/UIKit.h>
#interface PopupView : NSObject
+ (void)addSubview:(UIView *)view;
+ (void)show;
+ (void)hide;
#end
PopupView.m:
#import "PopupView.h"
#implementation PopupView
+(UIView *)sharedView {
static UIView *_view = nil;
static dispatch_once_t onceToken = 0;
dispatch_once(&onceToken, ^{
_view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, [[UIScreen mainScreen] bounds].size.width, [[UIScreen mainScreen] bounds].size.height)];
_view.backgroundColor = [UIColor blackColor];
_view.alpha = 0.6;
UITapGestureRecognizer *singleFingerTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(hide)];
[_view addGestureRecognizer:singleFingerTap];
});
return _view;
}
+ (void)addSubview:(UIView *)view {
UIView *v = [PopupView sharedView];
[v addSubview:view];
}
+ (void)show {
UIView *v = [PopupView sharedView];
v.frame = CGRectMake(0, 0, [[UIScreen mainScreen] bounds].size.width, [[UIScreen mainScreen] bounds].size.height);
id<UIApplicationDelegate> appDelegate = [[UIApplication sharedApplication] delegate];
[[appDelegate window] addSubview:v];
}
+ (void)hide {
UIView *v = [PopupView sharedView];
[v removeFromSuperview];
[v.subviews makeObjectsPerformSelector: #selector(removeFromSuperview)];
}
Usage:
UILabel *l = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 200, 21)];
l.text = #"Hello";
l.textColor = [UIColor whiteColor];
[PopupView addSubview:l];
[PopupView show];
Or course instead of a label you can put any view(s) you want.