SDCAlertView

SDCAlertView doesn't just look like a system alert in terms of user interface elements, it is the result of completely reverse-engineering UIAlertView. View hierarchy, labels, buttons, animations, user interaction; everything has been looked at and incorporated as much as possible.

You can think of SDCAlertView as UIAlertView on steroids. It has added functionality such as a contentView property and block syntax, while still keeping the UIAlertView look.

iOS 8 & `UIAlertController`

In iOS 8, UIAlertView was deprecated in favor of UIAlertController. SDCAlertView was also updated to include SDCAlertController, whose API matches its UI counterpart.

But that wasn't all, the entire view hierarchy changed again and even the way of presenting the alert changed. Fortunately, the new implementation was a lot easier to copy, though some sacrifices had to be made in terms of likeness. The culprits, two private classes by the name of _UIBackdropView and _UIBlendingHighlightView, were used quite a bit, and although UIVisualEffectView comes close to making it look exactly right, there are differences.

Ignoring minor differences (that you would really only see if you looked for them), everything that was possible in SDCAlertView is also possible in SDCAlertController, though probably in the form of a new API. SDCAlertController is backwards compatible with SDCAlertView, meaning you can replace your existing SDCAlertView instances with SDCAlertController instances, even if your deployment target is iOS 7.

This means that you should rarely use SDCAlertView anymore. Consider it, just like UIAlertView, deprecated and only use SDCAlertController moving forward. If you want to keep using SDCAlertView because it has functionality SDCAlertController does not, open an issue. This is considered a bug.

Installation

The easiest way to install is, of course, by using CocoaPods. The name of the pod is SDCAlertView.

If you're not using CocoaPods, you need all classes in the Source directory.

The project also depends on RBBAnimation (SDCAlertView only) and SDCAutoLayout. These dependencies are automatically handled for you if you use CocoaPods.

Usage

SDCAlertController is for use in iOS 7 or higher only. It will not work properly on iOS 6.1 or below. Using the library is very simple: just import SDCAlertController.h and use it as you would UIAlertController.

Basic

Showing a basic SDCAlertController alert looks just like showing a basic UIAlertController alert:

SDCAlertController *alert = [SDCAlertController alertControllerWithTitle:@"Title"
																 message:@"This is a message"
														  preferredStyle:SDCAlertControllerStyleAlert];
[alert addAction:[SDCAlertAction actionWithTitle:@"OK" style:SDCAlertActionStyleDefault handler:nil]];
[alert presentWithCompletion:nil];

Or you can use one of the convenience methods:

[SDCAlertController showAlertControllerWithTitle:@"Title" message:@"This is a message" actionTitle:@"OK"]

`contentView`

Of course, you're not using SDCAlertView's full potential unless you are using the contentView:

SDCAlertController *alert = [SDCAlertController alertControllerWithTitle:@"Title"
																 message:@"This is a message"
														  preferredStyle:SDCAlertControllerStyleAlert];
[alert addAction:[SDCAlertAction actionWithTitle:@"OK" style:SDCAlertActionStyleDefault handler:nil]];

UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] init];
spinner.activityIndicatorViewStyle = UIActivityIndicatorViewStyleGray;
[spinner setTranslatesAutoresizingMaskIntoConstraints:NO];
[spinner startAnimating];

[alert.contentView addSubview:spinner];
[spinner sdc_horizontallyCenterInSuperview];
[alert.contentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-[spinner]-|"
																		  options:0
																		  metrics:nil
																			views:NSDictionaryOfVariableBindings(spinner)]];

[alert presentWithCompletion:nil];

Dismissal Prevention

You can use the shouldDismissBlock to prevent an alert from being dismissed:

SDCAlertController *alert = [SDCAlertController alertControllerWithTitle:@"Title"
																 message:@"This is a message"
														  preferredStyle:SDCAlertControllerStyleAlert];
[alert addAction:[SDCAlertAction actionWithTitle:@"OK" style:SDCAlertActionStyleDefault handler:nil]];

alert.shouldDismissBlock = ^ BOOL(SDCAlertAction *action) {
	return NO;
};

[alert presentWithCompletion:nil];

Styling and Appearance

SDCAlertController is a normal view controller, so applying a tintColor to its view will color the buttons and any subviews you add to the contentView. If you are looking for more customizations, create a class that conforms to the SDCAlertControllerVisualStyle protocol and set it as the visualStyle on an SDCAlertController instance. You can also subclass SDCAlertControllerDefaultVisualStyle for a set of default values that you can then override as needed.

If you're feeling particularly adventurous, you can use a different transition/animation by creating a class that conforms to UIViewControllerTransitioningDelegate and setting it as the alert's transitionCoordinator. Transitioning is implemented using default iOS 8 custom view controller transitions, so anything you can do with a normal view controller, you can do with an alert controller.

Backwards compatibility

SDCAlertController will in most cases be backwards compatible with SDCAlertView. However, most is not all, and if you need to fine-tune an alert just for iOS 7, you can still do that:

SDCAlertController *alert = [SDCAlertController alertWithTitle:@"Title" message:@"Message" preferredStyle:SDCAlertControllerStyleAlert];
// ... configure alert with content view, text fields, buttons, etc ...

if (alert.legacyAlertView) {
	// ... use alert.legacyAlertView to make iOS 7 modifications
} else {
	// Keep using original alert
}

[alert presentWithCompletion:nil];

Behavior different from `UIAlertController`

With the introduction of SDCAlertController, pretty much all behavior in alerts could be replicated. If you use the legacy SDCAlertView, you may run into some additional problems as described below:

Special interaction with the system. The system does not consider instances of SDCAlertController actual alerts, which means that won't experience the normal system interaction you'd expect from a normal alert. This also means that combining UIAlertView with SDCAlertView (or SDCAlertController) is a bad idea.
SDCAlertView only: UITextField placeholders in different languages. "Login" and "Password" are entered as localized strings, but they aren't actually translated.
SDCAlertView only: Some behavior is purposely not ported from UIAlertView. These cases are discussed in SDCAlertView.h.

New in 2.0

What's New:

All new API that matches and extends UIAlertController
Ability to always show buttons horizontally or vertically
Backwards compatible with SDCAlertView (1.0)
More stylistic elements you can style (alert width, button separators, text fields, etc.)

Support

I'm pretty active on Stack Overflow, so please use that if you have any questions. You can also use Twitter to contact me directly.

If you are experiencing bugs, feel free to post an issue or submit a pull request. I don't bite, promise!

Credits

Some credits are in order:

Robert Böhnke (@robb): RBBAnimation
Lee McDermott (@lmcd) for reverse-engineering the showing and dismissing animations.

And everyone else who contributed by reporting issues, creating pull requests, or in some other way!

longlongjump/SDCAlertView