What’s New in Cocoa Touch

Session 203 WWDC 2013

iOS 7 introduces many enhancements made to the Cocoa Touch frameworks that will accelerate your development time and improve your app’s user experience. Get an overview of the changes to UIKit and other system frameworks, and find out which sessions you won’t want to miss.

Thank you, thank you.

Welcome to this morning's session for what's new in Cocoa Touch.

If you were here for the Building User Interfaces for iOS 7 talk with Jason Beaver and Andy Matuschak, they had a lot of really pretty pictures.

They went into some fantastic detail about the design aspects of iOS 7.

And I'm going to spend a lot of time on the actual API that you're going to be using in order to implement a lot of the stuff that they talked about.

So if you weren't able to get into the room, if you're listening to this on the tape, you probably want to go back and watch that talk on video first and then start in here.

So, let's get started.

One of the things that you'll notice, of course, is that stuff used to look like this.

This wouldn't be a presentation of mine without a picture of my dog.

But now, it has a little bit different look.

And again, they spent a lot of time talking about how this you know, the reasons behind this and how this works in the previous talk, so please make sure you go see that.

I'm going to spend, again, a lot more time on the really low level details here.

So first, we'd like to talk about adaptive multitasking.

So in iOS 6, if you were a multitasking app, you fell into one of the void categories or the audio categories and things like that.

So we're adding new mechanisms for you to be able to keep your content fresh and to be able to keep the illusion as if your application is running all the time in iOS 7.

And that involves three new things, background fetching, remote notifications, and background transfers.

So for background fetching, what you'll do is you'll add this new fetch category to your background mode in your application's Info.plist.

At that point, your application will be launched opportunistically.

So what we're doing here is watching the user's patterns for how they use your application.

And if we notice that, for instance, they're firing that application up every day at 7:55, we might fire you up at about 7:50 and say, "OK, go ahead and do this fetch," you'll get a new delegate method on UIApplication, application performFetchWith CompletionHandler.

And the idea here is you'll get called back at this point, say, we fired you up, you go off and do your network traffic.

And then at the end of that, you're handed a completion handler that you have to call.

That's how you tell us when you're done with your transfer.

The background fetching interval is controlled by this method on UIApplication.

It's setMinimumBackground FetchInterval.

You can use one of these two constants, UIBackground UIApplicationBackground FetchIntervalMinimum which is the slowest callback interval that you can give us.

ApplicationBackground FetchIntervalNever is please don't call me at all.

You'll have to call this method at launch.

Make sure that you get set or you can turn yourself off during your run.

And your own values above minimum will work as well.

So, for the remote notifications mechanism, if you're using if your app uses a server and the server knows that it has new information for one of your applications, you'll be able to get a push notification from the server and you'll get called back on this delegate method application didReceiveRemoteNotification FetchCompletionHandler.

And you'll also add that remote notification background mode to your Info.plist.

The handler here is, again, your opportunity to go out and do a bunch of work 'cause the userInfo dictionary is the push notification userInfo dictionary you've been getting before.

And again, when you go out and complete that, you'll call the completion handler with a UIBackgroundFetchResult.

And you don't have a lot of time to be able to do these things.

You've got a certain fixed amount of time.

If you don't call that completion handler in time, we may not actually fire you up the next time for either an opportunistic fetch or for a remote fetch.

So you need to make sure that you're getting your work done in a very short amount of time.

The UIBackgroundFetchResult, this is the completion handler signature.

When you call the completion handler, you're going to pass in one of these three values, ResultNewData, ResultNoData, or ResultFailed.

And this is how you tell us exactly what happened so that we know "Well, if the result failed, maybe we'll call you back again in a few minutes and maybe it will succeed then."

Or if you had no data, then we know that "Well, maybe every day at 7:50, there isn't any data and we don't actually need to fire you up."

All right, so that gives us some ability to be able to tune the behavior of the system to your user's behavior and your app's behavior as well.

So the new multitasking also has new Foundation API and NSURLSession.

So this is really a replacement system for NSURLConnection.

It handles data, upload and download tasks.

Sessions have identifiers, so you can actually restore from an identifier much the same way you can create things from state restoration.

There's a new delegate on UIApplication that gets called.

So if we know that you've got one of this background transfers going, you may have to fire up in order to handle things like authentication or transfer of data.

So application handleEventsFor BackgroundURLSessio: completionHandler gets called.

You get the session identifier.

We instate the session identifier the URLSession from the identifier and then do your behaviors.

So and again, here you're going to call the completion handler when you're done handling the callbacks.

And this completion handler just is is a void void, so you can just call it immediately.

There is a talk on What's New in Foundation Networking in the Mission, Wednesday at 9:00.

If you're doing any this kind of downloading or work with connections or sessions, you're definitely going to want to go see that talk.

So, you saw in the previous talk about all the changes that we've made for rendering and things like that, so let's talk about views and images a little bit.

We have some new image rendering modes in UIKit to deal with the way that you might actually display an image.

So, if you are working with template images before, you are probably going out to UIImage imageNamed, pulling an image off of disk, calling rendering context with a bunch of color and stuff like that and then slamming that color in.

So you actually do a bunch of work to be able to colorize a template of image.

This actually takes care that for you.

So once you have an image in hand, you're going to call UIImage imageWithRenderingMode.

And that rendering mode has three options.

Automatic means that we will do something with this image in a given context.

I'll talk about that in a second.

ImageRenderingModeAlwaysOriginal means always use the pixels as they came off of disks.

So if you've got a non-template image and you want to make sure that it doesn't get changed when it's put into a different context, you'll be able to use this.

Template means go ahead and colorize it or apply the template the way that the context defines it.

So what's the context?

The context is defined by a new UIView property called tintColor.

So, Andy talked about the fact that we've taken the tintColor concept and hoisted it all the way up to UIView, right.

So UIView now has this top level tintColor idea.

It's hierarchical.

You can set it on your window which will push the tintColor all the way through your application and things like controls and images will respond to that.

And you can also pull from that.

So, if somebody set it on a higher view in your view hierarchy and then you go down to a much lower view and call tintColor, you'll find out what the tintColor is.

You can render in context with that tintColor if you like or just find you know, use it for your own purposes.

What does this look like?

So, the default tintColor is this blue that you use.

What I've got here is a top level UIView.

There's a UIImage view there which has the little chevron and that's a UIButton that says "Onward."

And if you call, for instance, set tintColor red, the only thing I've done here is that image has the previous on image rendering mode set to template.

So if I call set tintColor red, everything that's in that view hierarchy inherits that tintColor.

So you don't have to do any of the rendering context anymore and all of our controls will take care of this.

This is a really good way to be able to apply, say, a theme color or a signature color to your application.

We also have this thing called the TintAdjustmentMode.

And when we present popovers on the pad or when present alert sheets on the phone, when we cover the content, we're going to put a dimming view over that.

And one of the things that we'd like to be able to do is indicate that things with a signature tintColor are no longer inter-actable.

And so, the TintAdjustmentMode allows us to say, "OK, this is a gray automatically desaturation.

If you don't want that behavior, you can change the TintAdjustmentMode so that it doesn't desaturate, OK."

So this is what it looks like with it's desaturated.

You can tweak that if you do actually want that those elements to not get changed.

When you find out about changes to the tintColor, frequently this kind of tintColor changes don't require layout changes.

You don't have to go back through and re-layout all your views.

You just need to change the colors, right.

If you implement tintColorDidChange on your UIView subclass, you'll get called and told when either somebody changes the tintColor up at the top level or the view hierarchy which you inherit, or when somebody calls set tintColor explicitly, or when any of these TintAdjustmentMode changes occur.

So that's your opportunity to do things like call the tintColor from high in the hierarchy, do a rendering context, and get the look with your tintColor that you want.

So View Animations can be a little tricky.

And we've introduced a new method called performWithoutAnimation.

And by introduce, I mean, we discovered that we were needing this a lot and we probably figured you guys needed it a lot too.

It's very easy to get caught up in either some of UIKit's default animation block or some animation block that you've created elsewhere.

And you can even do some layout changes or some behaviors that really require fixed layout that goes into a view hierarchy so that it doesn't get accidentally animated if these things happen.

So you can call UIViewperformWithoutAnimation.

This is a class method.

And anything you put in that block will happen instantly so it won't get animated when it gets into a view hierarchy or anything like that.

So this avoids a little effects where you created something, for instance, with CGRectZero and then suddenly it expands out during an implicit animation block.

The other thing that we've done is we've also added new UIViewAnimation level KeyframeAnimation API.

So you don't have to drop down the CAKEyframeAnimation anymore.

You can use animateKeyframesWithDuration delay options animations completion.

So this looks very similar to the UIViewAnimation API you already have.

Once you've got that you can also put in addKeyframeWithRelativeStartTime relativeDuration animations.

And you can compose this with the UIViewAnimation blocks as well.

So what's you're getting here is the ability to do things like start animations consistently at relative times, have those animations run a proportional value of the containing animation.

And there are a ton of options for this.

Some of them are familiar if you've been using the UIView Animation mechanism before.

So UIViewKeyframeAnimation options, layoutSubviews, AllowUserInteraction, all of those are the same as the UIViewAnimation API you're already using.

There are few, OK.

And there are new timing methods for calculating how those relative values will run through the animation.

So this should be a really easy way to be able to do the really subtle, really timed animations that you'd had to dropdown to KeyframeAnimation for.

So, you can stay up at the UIView level here now.

Andy talked a little bit about motion effects in the previous talk.

Motion effects are the things where when you pick up the device and you start moving it, that you get those effects like things are floating above or below various aspects of the interface.

Motion effects apply relative values to key paths of a view.

So what you'll do is specify which key paths you want, those things will get applied to the view.

And it applies the animatable properties of the view.

So if it's a CA animatable property, you'll be able to use it with motions effects.

And the idea is that you're going to produce a very subtle effect that really intrigues your user and really indicates the content or the focus of your application.

So the motion effects the easiest motion effect to use is a canned one that we have in UIKit called UIInterpolatingMotionEffect.

There's one initializer and it was KeyPath type.

And the KeyPath is the property on the view that you want to effect, and the type is one of these two things.

It's either along the horizontal axis or along the vertical axis.

And so, you'll specify, if you want to do something in both, you'll have to create two of these and decide with KeyPath and which type you're going to be affecting.

It interpolates between the minimumRelativeValue and the maximumRelativeValue, right.

So you'll be able attach these to a view.

And having it attach to those views as the device moves will take care of doing all the application of that effect to the view.

So you can do things like change the center, change the size, change the offset, you know, all of the various animatable properties, you can change the frame as well.

If you want to write your own, you can do that.

You can use the UIMotionEffect Abstract superclass.

There's one method on it, keyPathsAndRelative valuesForViewsOffset ViewerOffset, there we go.

The ViewerOffset is expressed we don't use UIOffset very much in our API if you've seen but just as a reminder, that's a horizontal and vertical offset.

So horizontal is obviously that the axis that we're using for the interpolating motion effect as well as the vertical.

You'll overwrite this and provide you'll get a you know, provide a dictionary of the key paths that you want and what values given the inputs of that UIOffset.

So this is how you can write all of your own more complicated motion effect.

You'll add or move them to the view with just addMotionEffect and removeMotionEffect.

And if you need find out what affects are on the view, you can go ahead and call the motion effect's accessor.

These are really, really interesting APIs because there's not much to the API but it concentrates on behavior.

So what you'll be able to do is add these things gradually to your application and touches here and there.

And it'll really make your application pop, so.

We've made some enhancements to collection views, all right.

Collection view is really flexible.

There are really interesting ways to be able to combine them.

And you're really able to do a large scale layouts without lots and lots of individual layouts subview tweaky little calls.

One of the things that we've added is a convenience API for switching between two collection view layouts, setCollectionViewLayout animated completion is a new method which compliments the old one that didn't have the completion handlers.

Now, if you are animating it, you can find out exactly when that animation completed.

So this is just a little one off method to help you out with that.

But one of the things we've done in terms of switching between two different collection view layouts is added a really easy way to be able to interpolate between the two with what's called UICollectionView TransitionLayout.

And a transition layout is a UICollectionViewLayout object.

You hand it two other collection view layouts, the current lay out and the next layout, and then we'll take care of interpolating between those two as you drive the transition progress.

So if you're needing to update values in there yourself for a custom subclass, you'll get called with updateValueForAnimatedKey or value forAnimatedKey so you find out what's happening as the CollectionViewTransitionLayout is firing.

But for the most part, you'll just be able to call this transition, setTransitionProgress property and say, "You know, I'm 10 percent, 20 percent, 30 percent, 40 percent of the way through it," and we'll take care of interpolating between all of the elements in your collection view layout in the starting collection layout and the ending one and take care all of the movement of the views and everything else for you.

So, this transition API is really handy if you combine it with the UIView controller, API to be able to switch between navigation controllers and handoff that collection view itself that we're talking about in the previous talk.

So, collection view layout, very powerful, very easy now be able to ship between two different layouts.

View controllers, of course, are the unit of composition for UIKit.

We've made a lot of changes to view controllers to accommodate the new API the new appearance.

We've also made a number of changes, try to make it easier for you to be able participate in a lot of the things that we do in terms of canned animations and stuff like that.

But of one of the first things I want to mention is wantsFullScreenLayout.

So, a lot of what you were doing in iOS 6 in terms of full screen layout was dealing with things like this.

Here's a picture of the dog.

He was helping me out with my presentation last week, cleaning things up or, as I like to call it, snoring.

This is a non-full screen layout iOS 6 view controller.

And if you were going to call wantsFullScreenLayout yes, and then if you set your navigation bar appearance to be translucent and your status bar appearance to be translucent, you get something like this and this is the classic barb with full screen layout which is, you know, you're not really I'm not stretching out the content here to make sure that it fits the full screen layout.

One of the things that we want to make sure that you guys are doing is using full screen layout because iOS 7 deprecates this property entirely.

wantsFullScreenLayout is no longer useful.

We will treat as if it were yes all the time for [inaudible] or after 7.0.

So, with Bud resting here, you can kind of see how the content is slid up under the navigation bar and but the way that in iOS 7 that we're going to have you specify which edges get stretched in a situation like this is with this extended edge API.

And some of this is in flux, but this is what in Seed 1 right now.

It may look a little different.

We're still tinkering with some of the names.

But the extended edge API here is specifying that the edges for extended layout for your view controller, this property is going to be all by default.

We want to be able to take you views and expand them to their full content size.

But if you want to specify only the left and right edges and leave the top and bottom the way they are, you would logically [inaudible] some of the flags together.

You can also check if the extended layout includes the opaque bars.

This is no by default in iOS 7.

And automatically AdjustsScrollViewInsets is how we're going to take a look at the scroll view that's probably at the top of your view controller and say, "OK, I can adjust the content insets to make sure that the content is actually positioned correctly inside a navigation controller or a Tab bar controller because now all of those bars, the Nav bar and the Tab bar and the Tool bar or Tab bar at the bottom have that blur translucent effect."

So we want to make sure that all of your content is winding up in the right place.

These methods are how we're going to help you adjust that content automatically.

So automatically AdjustsScrollViewInsets will take of a lot of those numbers of you.

And this also takes care things like when the device rotates, exactly how far you adjust those insets because, of course, on the phone, when you rotate to landscape, the Nav bar's a little shorter, so.

We also we have new API for content size.

So in many cases, we take a view controller from you guys or from you take one from another component like address book or something like that, and you're going to make a child view controller of your view controller, you want to find out how big it is.

So preferredContentSize is a way for view controller to tell UIKit or tell parent view controllers, "I'd like to be this size," right.

And this is actually replacement for the content size review in popover call because we're going to use this call everywhere now in iOS 7.

So if you want to tell us how big your view controller ought to be right when we initialize it, this is your opportunity to do it.

And it's a great way to be able say, "OK, I'm going to take this view controller, make it a certain size, how big do you want it to be?"

So, layout is very important.

In terms of the status bar appearance, there's new behavior for the status bar and the status bar actually has no background.

What's you're seeing in iOS 7 is the navigation bar getting taller and the status bar being over laid on it.

UIStatusBarStyleDefault is what you see it's got what we call "Dark content", meaning the status bar information is all in black or dark color.

Status bar UIStatusBarStyleLightContent has white text up there.

So if your content is going to be dark or otherwise not contrast with the default, you may want to set UIStatusBarLightContent.

And this refers to the content of the status bar itself.

These other two properties, StatusBarStyleBlackTranslucent and StatusBarStyleBlackOpaque, those refer to the background which really doesn't make any sense anymore.

They don't have a background now.

So, those are deprecated.

You can stop using them.

So if you recall with there are two major sections of UIKit or behaviors in UIKit where we do these transitions, where you slide, you do a push pop in navigation controllers or for a modal transition, the presentation slides up from the bottom.

Those are all canned transitions.

You haven't been able to participate in those until iOS 7.

So iOS 7 introduces custom transitions in all of our API that does it.

So you're talking about navigation controller push and pop, we've got modal transitions.

You'll be able to drive these both off a timer.

So if you're just doing a straight push or a straight pop, you'll be able to participate in that with your own transition, or you'll be able set up an interactive transition with the user actually sliding their thumb across and you'll get all kinds of events about things like whether or not they made it all the way across [inaudible], whether they canceled the transition, or whether they made it all the way across and actually finished the transition.

There's a new delegate method of UIViewController called transitioningDelegate.

The transitioningDelegate is going to be the object called to find out how to do this transition.

So, let's say you've got an UINavigationController, you're pushing a new view controller on it.

If that view controller has a transitioningDelegate property set on it, that object's going to get one of these methods, animationController ForPresentedController, presentingController, sourceController.

So the sourceController or the presentingController, you're given all of the view controllers that are participating in the transition.

And animationController ForDismissedController, this is basically the equivalent of a pop or a dismissal of a modal transition.

The objects conform to this protocol, UIViewController AnimatedTransitioning protocol.

The protocol is really useful here because it means that you can specify any object.

It can be another view controller.

It can be an object of your own type.

As long as it conforms to this protocol, you'll be able to drive these transitions.

For interaction, we'll ask the transitioningDelegate for an interaction controller for a presentation or an interaction controller for dismissal when the thing's going away.

So presentation on Nav contoller is, of course, a pop, the dismissal would be I'm sorry presentation's a push, dismissal is a pop.

It has its own protocol as well.

So you are in a maze of twisty little protocols all alike.

They're actually not all alike.

They're very, very powerful.

And for instance, the AnimatedTransitioning protocol, it's pretty simple.

The transitionDuration, animateTransition, and animationEnded, these are all methods that your transitioning object will get called on.

You can return the transitionDuration for a given transition context.

The animateTransition for a transition context.

This is when you're told, "Go ahead and do the animation."

We're ready to go do your slide, do your fading, do your twirly transition there.

And animationEnded, this is how you find out when that transition ended.

So, the animated bits, this is for the parts where things are happening on a timer, things are happening on our context.

Custom transitions for UIViewController InteractiveTransitioning, you'll be told when to start the animation, the interactive transition, right?

So just like the other API, this is where you're going to start the interaction.

And the completionSpeed and the completionCurve are used to find out when the user got far enough across, did they finish or not, and if they didn't or if they did, how fast do you want the rest of the animation to run, right?

So when you're sliding your thumb across and you're driving one of these things based on user gestures, if you get all the way across, then it must have run the completion, I think half way across, a little bit more than half way.

And that means, yes, you can actually do the rest of the transition as if they completed.

This is how you specify how long it takes and what the curve is.

And the curve is the UIAnimation bit.

Here's the meat of it.

The UIViewController ContextTransitioning, again, this is a protocol that your objects conform to.

This is where you put all of the information that you need in order to drive these animations.

You'll need to supply a container view.

Frequently, this is the parent view controller's view.

Whether or not it's animated, whether or not in it's interactive, whether or not a particular transition was canceled, you'll be able to do all of that and find out from this that the transition was canceled.

You'll also specify you can specify presentation styles and all kinds of stuff.

This is incredibly powerful.

And this is the mechanism that we're using, for instance, to do the slide transition in navigation controllers now, so you'll be able to participate in all of those things yourself.

We've got a Custom Transitions Using View Controllers talk in Pacific Heights on Thursday at 11:30.

If you've ever wanted to be able to participate in these things, that's the talk to go to.

So, let's talk a little bit about some new stuff in State Restoration.

One of the things that we've noticed in terms of our own usage of state restoration is there are times where your content or the state that you're restoring doesn't really match the snapshot we took when your app got killed before, right.

So, one of the new methods that's available in state restoration is ignoreSnapshotOn NextApplicationLaunch.

So, you've discovered as a function of starting through the state restoration mechanism that allow, you know what, the snapshot that's going to get taken won't make any sense.

You can call ignoreSnapshotOnNextAppLaunch.

That method will prevent us from taking a snapshot.

You'll get the default ping when it comes up.

You'll be able to still do state restoration things when your app comes up but it won't have the old content if it doesn't make sense.

One of the other things that's been a very popular request is for objects that aren't views or view controllers to be able to participate in a state restoration machinery.

So you may have your own model objects or you may have your own informational objects or created models, things like that, that are all going to need to participate in state restoration, you can use this method, registerObjectFor StateRestoration restorationIdentifier.

So just like view controllers can have restorationIdentifiers just like other views can restorationIdentifiers, you'll now be able to specify a restorationIdentifier for arbitrary objects.

You'll call UIApplication registerObject ForStateRestoration restorationIdentifier, tell us the object, tell us the identifier.

And as long as you conform to the state restoring protocol, we'll go ahead and restore that object along with everything else during the state restoration mechanism.

So this is a great way be able hand us more information and you guys can do a little bit less work in terms of archiving and saving off your additional state 'cause we'll keep track of it for you.

We also now support a couple of interesting features.

If you're using Core Bluetooth and you've paired up with a Bluetooth Central or a peripheral in your application, we can now state restore those things for you as well.

So UIApplicationLaunchOptions BluetoothCentralsKey, when you get the state restoration method callback, one of these things in the userInfo dictionary will be the all of the identifiers for the Bluetooth Centrals that we can determine that were present when you went down before.

So, you'll be able to pull all those back up and reconnect very easily.

And if you were connected to peripherals, you'll be able to get to all of those peripherals back out of the array that's returned by this key as well.

So, you don't have to go back and try to repair everything without and keep track of all of that stuff because we'll take care of it for you.

Let's talk a little bit about AirDrop.

AirDrop is new iOS 7.

You've got the Activity View Controller that comes up in AirDrop as an option.

One of things that you'll do is go ahead and look in the ActivityItemSourceProtocol, make sure that your object conforms to that.

You'll update your Info.plist which will create or register the UTIs for the things that you're going to be able to accept as an AirDrop.

And there's a new Documents/Inbox directory.

This directory lives in your application's wrapper.

And that wrapper the Inbox directory will accept all of the things that are being AirDropped to your application, right.

So whenever your application activates, you'll want to take a tour through this directory and see if there's anything new in there that you'll want to pull in.

New documents, new things that other users have shared with you are going to come along with these app activations.

And you should check this even if you don't get the usual application:openURL :sourceApplication :annotation: call because these things are going to come in from other places and they may come in frequently.

So somebody AirDrops 10 or 12 things to you, you might want to be able to queue that work up.

You don't want to do all of the transition work of "Oh, I received this thing and then I'm going to move it over here and process it somehow."

You want to defer that until a point where the application is you want to make sure that the application to stay responsive.

You don't want to block the user doing that.

So you might want to queue this stuff up if you discover that there are 12 or 15 things in the Inbox directory.

This is tremendously exciting because it's going to be a very easy behavior-base way for you guys to add really, really, really subtle effects but really fantastic physics-base effects and animations to your application.

The idea is to be able to provide fluid, very responsive animations that enhance the interactions in your application, all right.

This is not something that you should be using that says, "Hey look.

This is animating and it's bouncy and it's physics."

It should be really, really carefully considered.

And the concentration of the API is on behaviors.

We don't want you to have to write lots and lots of code to be able to get basic things like views dropping down from the screen.

The Lock Screen effect where you bounce the camera, you bounce the Lock Screen to find the camera, that's very few lines of code.

It's attaching behaviors to a view rather than having to write all of the physics behavior behind it.

What you'll do is create one of these UIDynamicAnimator objects.

And a Dynamic Animator concentrates on a reference view.

Most of the time, you'll be using this view initializer, initWithReferenceView.

That view contains it's going to apply behaviors to everything in it.

You'll add dynamic behaviors or remove dynamic behaviors depending on what's going on.

And you can also find out if you're writing one of your own, all of the items in a given rect.

So you may want to be able to do things like only look at the visible rectangle and only animate those things that are actually visible if you're going to write your own dynamic animators.

You can also find out whether or not it's running so you'll be able to know whether or not the animation has come to rest.

And there's a delegate that tells you also when things come to rest, when things started up again.

So, one of the things that we're doing with this is making sure that you're concentrating on the behavior, we're concentrating on the bookkeeping for the physics.

Dynamic behaviors are just a tree of all kinds of supported things for gravity and collisions and stuff like that.

So you'll add or remove child behaviors to a given dynamic behavior.

And a dynamic behavior defines all kinds of timings and things like that.

One of the things that you can do is you can also implement an action block.

It gets called at every frame of the dynamic animation.

So if you need to do something that our built-in behaviors don't do or can't really support without additional help from the system as it's running, you can implement this Action method.

It shouldn't be too common, but you can do it.

What are those supported behaviors?

Attachments, so if you want to be able to have one view follow another view, you can attach the two views together and they'll animate together.

CollisionBehavior, if two views are going to bump into each other and bounce off of each other, you can specify that.

GravityBehavior, how much gravity is involved, and that's how we control how fast that Lock Screen drops back down when you're bringing the camera up.

A PushBehavior is if you give it a view an impulse as if you were giving it a force and it's going to slide off and bump into something else.

We have a new unit of measure I think that we're introducing there.

You'll have to go to the Animation talk to find out what it is.

A SnapBehavior, SnapBehaviors are really interesting.

They allow you to be able to specify essentially a well or a snap so that when a view overlaps another one, it folds into place at that location.

And if you need to do something that isn't setup here, UIDynamicItemBehavior is your opportunity to participate in the system yourself.

So DynamicItem is just something that conforms to this protocol, center, bounds, transform.

And that's how we move things around on the screen during the animations.

There are two Dynamics talks, Getting Started with UIKit Dynamics right here at 4:30.

The demos are awesome.

And Olivia will an absolutely fantastic job talking about this.

Advanced Techniques with UIKit Dynamics, Thursday here at 3:15.

It's very composeable.

It's tremendously powerful.

There's a lot of stuff here.

If you're interested in this kind of physics-base animation, you're going to want to see this talk.

So, let's talk a little bit about text.

We've always had a concentration on beautiful typography and really, really crisp beautiful text.

In IOS 6, we introduced all of the NSAttributedString components that enable you to do things like mix and match runs of text with different styles.

You know, bold, italic, underline, things like that.

We also piped that all the way through UIKit.

So, buttons and text fields and text views and stuff like that.

Really, we're able to do you're able to do far more typographic things with it.

We've introduced a new dynamic types sizing mechanism.

So, dynamic type, this is the text size view controller that's in settings.

The user can go and slide this slider left and right to decide how large or small they want their primary content to be, right.

And that slider is piped to the preferredContentSizeCategory method property, rather, on UIApplication.

This is how you find out what the user selected.

And that preferred content size categories can be the essentially, the text size for the primary content text that you're using and that'll be based with one of these values, extra small, small, medium large, extra, it's like a t-shirt but with for text.

So, this specifies sort of the base relative size of the text.

When it changes, you'll find out when it changes because you'll get a ContentSizeCategory DidChangeNotification and a ContentSize CategoryNewValueKey, and this is your opportunity to be able to go back, find out what changed, relay out your text.

So, again, with the dynamic text bits, you're going to want to be using auto-layout because that will help you scale your layout as the text size changes.

They mentioned this one method here, preferredFont ForTextStyle, right.

Most of our content falls within certain bins.

There's a body.

There are some headlines or a subject line or something like that or a smaller text that's interstitial like a caption for a picture, something like that.

All of these styles, you can pass into preferredFontForTextStyle.

We'll go through and evaluate that, figure out what the appropriate size, weight, all of the things that would apply to that is in relative terms and produce a new UIFont for you to use.

So this method preferredFontForTextStyle is very, very important.

It's the single chill point to be able to get relative text styles and fonts for your application and they'll scale relative to the primary content size that you want.

One of the things that we've noticed is that the NSAttributedString system is very powerful.

You can specify attributes.

You can do all of these things.

But you're pretty much getting the rendering that we give you.

So in IOS 7, we talked about this a couple of times, but in IOS 7, we're introducing Text Kit.

Text Kit is an Objective-C API.

It's inspired by the Cocoa text system from OS X.

So if you've been using the Cocoa text system on OS X, a lot of the concepts that we're going to talk about here will be very, very familiar, and this wraps Core Text.

So this is our high level API for our low level text system.

So let's talk about the classes that are involved here.

This is just an application.

It's got a UITextView in it.

That UITextView has an NSTextContainer.

And NSTextContainer is the largest component of the text system for layout.

And then we get an NSLayoutManager.

And the Layout Manager is the thing that's actually in charge of doing all of the drawing and the bits.

And an NSTextStorage is the actual NSString that's backing all of this, right.

And one of the great things about Text Kit and one of the fantastic things about way this to setup is if you want to participate at any level of this, you don't have to subclass the whole stack.

You just subclass an NSLayoutManager if you want to change the way maybe glyphs render, or a TextContainer if you'd like to change the way text flows or wraps.

Or if you need to be able to manage your own specific kind of text storage that isn't just a straight array of Unicode characters, you can subclass that as TextStorage and you can participate at any level of this hierarchy.

Let's talk a little bit about TextView and TextContainer.

An initWithFrame textContainer is the new designated initializer on UITextView, OK.

So if you specify a nil TextContainer, you'll get the default that UIKit uses.

You can also find out what that TextContainer is.

And as a convenience, the layoutManager and textStorage methods are call-throughs to the TextContainer from UITextView.

We're just piping those through to make it a little easier to get to.

So, all you have to do here is if you're going to change your TextContainer, call that.

TextContainers get initialized with a size, so they get setup with a specific size for the frame that they're being laid out in.

And they also have a LayoutManager.

So if you're going to if you're going to subclass LayoutManager, you can provide your own subclass.

If you don't provide one here, again, you get our default, so you get the default behavior all the way down the stack.

You can also change the lineBreakMode and lineFragmentPadding.

So things that you've never really had a lot of control over before, where things break, how they break with the default break modes and the fragment padding for how things get split out.

lineFragmentRectForProposedRect atIndex writingDirection remainingRect, there are a lot more methods on TextContainer, and these are just a few of them.

But this is the kind of control you get.

Given a specific rectangle at an index and a character index of your Text Screen will tell you what the baseWritingDirection is, you'll fill in a remainingRect, in return, a rectangle for that.

So if you want to change where this stuff lays out, this is one place to do it.

So you're going to get exceptionally fine during control over where all of the glyphs wind up.

One of the most one of the coolest things we've done is exclusionPaths.

So, if you're doing a picture, for instance, of the flowers that you saw in the previous presentation, it's got an irregular path around it, that would've involved a lot of work to be able to try to figure out where is the bitmap, where are the places that it's overlapping.

With exclusionPaths, all you have to do is provide us a UIBezierPath.

The text will automatically flow around that path.

And as you change it, we'll re-layout it automatically.

[ Applause ]

It's a lot simpler.

LayoutManager has a bunch of different global options, things like showsInvisibleCharacters, showsControlCharacters, the hyphenationFactor you can tweak how aggressively words are hyphenated, usesFontLeading, whether reusing the leading from the font system or something else, and allowsNonContiguousLayout and hasNonContiguousLayout.

So, if you've invalidated a section of the text, we don't have to re-layout the entire [inaudible] one to be able to redisplay the text.

So NonContiguousLayout is a great performance when especially on embedded devices.

And this concept is almost directly from the OS X text system.

If you have NonContiguousLayout, you can find out from the LayoutManager here.

What does LayoutManager do?

LayoutManager is really the workhorse of the text system.

So a lot of the features involve things like invalidation and there are probably 15 or 20 invalidation methods.

One of them is something like invalidateLayout ForCharacterRange actualCharacterRange, so you'll be able to take portions of the layout and invalidate them yourself or find out when they're invalidated.

Glyphs and glyph properties.

If you've ever wanted to get involved with what winds up on the screen in place of something in your TextStorage, this is one part of LayoutManager's job.

You can find out many glyphs are in the run, that's just, you know, what characters are there.

glyphAtIndex and isValidIndex tell me what glyph is being used for the character at this index.

And then you can do things like getGlyphsInRange and you'll get a CGGlyph back with properties, characterIndexes and bidiLevels.

All of these things help you decide what's in the LayoutManager as well as what gets drawn.

So speaking of drawing, you'll be able to actually get involved with what hits the screen based on the text runs you have in your TextStorage.

So you can draw a background for a glyph range at point, that's how you'll be able to do things like put your own graphics behind things.

rawGlyphsForGlyphRange atPoint, if you want to put your own CGGlyphs in place of a range at a point, you'll be able to do that.

So you've got complete control over how text gets rendered on the system.

drawUnderlineForGlyphRange underlineType baseline all of these different styles, what kinds of underlines, what kinds of bold gets used, all of that stuff is controlled by the LayoutManager, you have all of these methods available to you.

So there is a fantastic control over text on iOS.

NSTextAttachment is another class in Text Kit.

You'll be able to put pictures and images inside the text runs inside of UITextView.

Much easier, yeah.

So, we are very, very serious about this.

This is an incredible technology.

It's a fantastic opportunity for you to really take control of the typography in your app, especially if you're writing advanced text processing applications.

We have three talks on this.

Introducing Text Kit, come back after lunch, after the lunch time speaker, we'll we've talking about it right here in the Presidio tomorrow.

Advance Text Layouts and Effects with Text Kit, that's going to get into all of the bits, things like all the LayoutManager stuff, where to overwrite things, that's in Mission, Thursday at 2:00.

And Using Fonts with Text Kit right here in the Presidio, Friday, bright and early at 9:00 AM.

You'll find out how to effectively use fonts from your application with Text Kit and everything else that that implies.

These are fantastic technologies.

It's all stuff that we're using in iOS all over the place.

If you don't take advantage of this, I'm not sure what to tell you.

This is fantastic stuff.

We're not the only people working on this stuff.

There are many, many, many new features across a number of different frameworks in iOS.

One of the more exciting things, Multipeer Connectivity, the Game Kit guys and the IMG guys have been working very hard at producing a new framework for local network connectivity involving things like session management, who's involved, who's joined a session, and multiplexing data across that session.

You'll be able to setup secure sessions yourself as well as file transfers and things like that.

So, if you're writing something that involves collaboration or you're writing a multiplayer game, this will be a fantastic talk to go to in Mission, Wednesday at 10:15.

If you are at the Platform State of the Union, you probably heard about SpriteKits.

SpriteKit is a cross platform, high performance, sprite-based game framework.

So, this makes it tremendously easy to be able to write fantastic iOS-based games, Mac OS X OS X-based games.

It has image atlas support and really tight integration with UIKit and Appkit.

One of the things that these guys did was to be able to pipe UIGestureRecognizers directly into this entire OpenGL-based rendering system.

So, you'll be able to do very idiomatic UIKit-like things with SpriteKit on iOS.

The game Controllers framework, you'll be able to pair arbitrary Bluetooth game controllers with your iOS device.

So if you're doing something with games and you want those shoulder buttons and the analogue joysticks and everything else to work, you'll be able to find out about all of that.

That's at the Integrating with Game Controllers talk in Pacific Heights at Tuesday at 3:15.

MapKit, of course, they have been very busy.

There's a new Directions API that you'll be able to take advantage of, 3D cameras for your maps, map tile overlays, snapshots of your maps.

They're working with Geodesics.

You'll be able do all of these things in your app for what's new in MapKit right here Thursday at 9:00.

CoreLocations adopted the new Bluetooth LE beacons bits, so you'll be able to take your device and actually turn it into a location-based beacon where people can find out how far away those beacons are.

There are some new region types or region monitoring and more control over the region monitoring you've had before.

What's new in CoreLocation, of course, in Presidio, Thursday at 11:30.

Accessibility is a huge deal for us.

One of the things that we are really proud of is making our apps as accessible as possible for users who are differently abled.

There's new UI there's new API to be able to participate in the Guided Access system.

So, Guided Access was a feature introduced on iOS VI.

Now, your app can actually tell the Guided Access system what's available to it.

Accessibility in iOS in Pacific Heights, Tuesday at 9:00.

If you're doing anything to make your app more accessible, please go this talk.

GamesCenter now also has a new turn-based API, so you'll be able to better manage turns in your application.

There's turns tabs, modes for bidding.

New leaderboard improvements and some system integrity features to make sure that nobody is packing max into your high score fields anymore.

So What's New in Game Center in Mission, Wednesday at 3:15.

There are many more talks and many more a labs than I can list here.

Please consult your schedule for that.

If you have any questions about the technologies that we've talking about, you know, John Geleynse and his team here, Jake Behrens is of course the UI Frameworks Evangelist, still wearing plaid every day this week.

And we also have, you know, all of these fine people.

If you're interested in games and things like that, some of these people are better to talk to.

So, thank you very much.

Come see us in the labs, take advantage for everything we've been talking about.

Thank you.

[applause]

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