A New Design

The iOS 7 UI has been completely redesigned. Throughout the system, a sharpened focus on functionality and on the user's content informs every aspect of design. Translucency, refined visual touches—and fluid, realistic motion—impart clarity, depth, and vitality to the user experience. Whether you're creating a new app or updating an existing one, keep these qualities in mind as you work on the design.

Apps compiled against the iOS 7 SDK automatically receive the new appearance for any standard system views when the app is run on iOS 7. If you use Auto Layout to set the size and position of your views, those views are repositioned as needed. But there may still be additional work to do to make sure your interface still has the appearance you want. Similarly, if you customize your app’s views, you may need to make changes to support the new appearance fully.

For guidance on how to design apps that take full advantage of the new look in iOS 7, see iOS 7 Design Resources.

UIKit Dynamics

Apps can now specify dynamic behaviors for UIView objects and for other objects that conform to the UIDynamicItem protocol. (Objects that conform to this protocol are called dynamic items.) Dynamic behaviors offer a way to improve the user experience of your app by incorporating real-world behavior and characteristics, such as gravity, into your app’s animations. UIKit supports the following types of dynamic behaviors:

• A UIAttachmentBehavior object specifies a connection between two dynamic items or between an item and a point. When one item (or point) moves, the attached item also moves. The connection is not completely static, though. An attachment behavior has damping and oscillation properties that determine how the behavior changes over time.

• A UICollisionBehavior object lets dynamic items participate in collisions with each other and with the behavior’s specified boundaries. The behavior also lets those items respond appropriately to collisions.

• A UIGravityBehavior object specifies a gravity vector for its dynamic items. Dynamic items accelerate in the vector’s direction until they collide with other appropriately configured items or with a boundary.

• A UIPushBehavior object specifies a continuous or instantaneous force vector for its dynamic items.

• A UISnapBehavior object specifies a snap point for a dynamic item. The item snaps to the point with a configured effect. For example, it can snap to the point as if it were attached to a spring.

Dynamic behaviors become active when you add them to an animator object, which is an instance of the UIDynamicAnimator class. The animator provides the context in which dynamic behaviors execute. A given dynamic item can have multiple behaviors, but all of those behaviors must be animated by the same animator object.

For information about the behaviors you can apply, see UIKit Framework Reference.

Text Kit

Text Kit is a full-featured, high-level framework for apps that need to handle text that has all the characteristics of fine typography. Text Kit can lay out styled text into paragraphs, columns, and pages; it easily flows text around arbitrary regions such as graphics; and it manages multiple fonts. Text Kit is integrated with all UIKit text-based controls to enable applications to create, edit, display, and store text more easily—and with less code than was previously possible in iOS.

Text Kit comprises new classes plus extensions to existing classes, including the following:

• The NSAttributedString class has been extended to support new attributes.

• The NSLayoutManager class generates glyphs and lays out text.

• The NSTextContainer class defines a region where text is laid out.

• The NSTextStorage class defines the fundamental interface for managing text-based content.

For more information about Text Kit, see Text Programming Guide for iOS.

Sprite Kit Framework

The Sprite Kit framework (SpriteKit.framework) provides a hardware-accelerated animation system optimized for creating 2D and 2.5D games. Sprite Kit provides the infrastructure that most games need, including a graphics rendering and animation system, sound playback support, and a physics simulation engine. Using Sprite Kit frees you from creating these things yourself and lets you focus on the design of your content and the high-level interactions for that content.

Content in a Sprite Kit app is organized into scenes. A scene can include textured objects, video, path-based shapes, Core Image filters, and other special effects. Sprite Kit takes those objects and determines the most efficient way to render them onscreen. When it comes time to animate the content in your scenes, you can use Sprite Kit to specify explicit actions you want to perform or use the physics simulation engine to define physical behaviors (such as gravity, attraction, or repulsion) for your objects.

In addition to the Sprite Kit framework, there are Xcode tools for creating particle emitter effects and texture atlases. You can use the Xcode tools to manage app assets and update Sprite Kit scenes quickly.

For more information about how to use Sprite Kit, see Sprite Kit Programming Guide. To see an example of how to use Sprite Kit to build a working app, seecode:Explained Adventure.

Game Controller Framework

The Game Controller framework (GameController.framework) lets you discover and configure Made-for-iPhone/iPod/iPad (MFi) game controller hardware in your app. Game controllers can be devices connected physically to an iOS device or connected wirelessly over Bluetooth. The Game Controller framework notifies your app when controllers become available and lets you specify which controller inputs are relevant to your app.

For more information about supporting game controllers, Game Controller Programming Guide.

Game Center Improvements

Game Center includes the following improvements:

• Exchanges give players an opportunity to initiate actions with other players, even when it is not their turn. You can use this feature to implement simultaneous turns, player chats, and trading between players when it is not their turn.

• The limit on per-app leaderboards has been raised from 25 to 100. You can also organize your leaderboards using a GKLeaderboardSet object, which increases the limit to 500.

• You can add conditions to challenges that define when the challenge has been met. For example, a challenge to beat a time in a driving game might stipulate that other players must use the same vehicle.

• The framework has improved its authentication support and added other features to prevent cheating.

For more information about how to use the new Game Center features, see Game Center Programming Guide. For information about the classes of the Game Kit framework, see Game Kit Framework Reference.

UIKit Framework

The UIKit framework (UIKit.framework) includes the following enhancements:

• All UI elements have been updated to present the new look associated with iOS 7.

• UIKit Dynamics lets you mimic real-world effects such as gravity in your animations; see “UIKit Dynamics.”

• Text Kit provides sophisticated text editing and display capabilities; see “Text Kit.”

• The UIView class defines the following additions:

  • The tintColor property applies a tint color that affects both the view and its subviews. For information on how to apply tint colors, see iOS 7 UI Transition Guide.

  • You can create keyframe-based animations using views. You can also make changes to your views and specifically prevent any animations from being performed.

• The UIViewController class defines the following additions:

  • View controller transitions can be customized, driven interactively, or replaced altogether with ones you designate.

  • View controllers can now specify their preferred status bar style and visibility. The system uses the provided information to manage the status bar style as new view controllers appear. You can also control how this behavior is applied using the UIViewControllerBasedStatusBarAppearance key in your app’sInfo.plist file.

• The UIMotionEffect class defines the basic behavior for motion effects, which are objects that define how a view responds to device-based motion.

• Collection views support UIKit Dynamics. Using this support, you can apply behavior objects to layout attributes to animate the corresponding items in the collection.

• The imageNamed: method of UIImage supports retrieving images stored in image asset catalogs, which are a way to manage and optimize assets that have multiple sizes and resolutions. You create image asset catalogs in Xcode.

• There is a new snapshot method on UIView and UIScreen creates a view that you can use to present your app’s content.

• The UIKeyCommand class wraps keyboard events received from an external hardware keyboard. These events are delivered to the app’s responder chain for processing.

• A UIFontDescriptor object describes a font using a dictionary of attributes. Use font descriptors to interoperate with other platforms.

• The UIFont and UIFontDescriptor classes support dynamic text sizing, which improves legibility for text in apps. With this feature, the user controls the desired font size that all apps in the system should use.

• The UIActivity class now supports new activity types, including activities for sending items via AirDrop, adding items to a Safari reading list, and posting content to Flickr, Tencent Weibo, and Vimeo.

• The UIApplicationDelegate protocol adds methods for handling background fetch behaviors.

• UIKit adds support for running in a guided-access mode, which allows an app to lock itself to prevent modification by the user. This app is intended for institutions such as schools where users bring their own devices but need to run apps provided by the institution.

• State restoration now allows the saving and restoration of any object. Objects adopting the UIStateRestoring protocol can write out state information when the app moves to the background and have that state restored during subsequent launches.

• Table views now support estimating the height of rows and other elements, which improves scrolling performance.

For information about the classes of this framework, see UIKit Framework Reference.

Store Kit Framework

The Store Kit framework (StoreKit.framework) has migrated to a new receipt system that developers can use to verify in-app purchases on the device itself. You can also use it to verify the app purchase receipt on the server.

For more information about how to use this new receipt system, see Receipt Validation Programming Guide.

Security Framework

The Security framework (Security.framework) adds support for syncing passwords between user's devices via iCloud. Apps can mark their keychain items for iCloud via a new keychain attribute (kSecAttrSyncronizable).

For more information about this attribute, see the framework header files. For general information about the keychain, see the Keychain Services Programming Guide.

Pass Kit Framework

The Pass Kit framework (PassKit.framework) includes new APIs for adding multiple passes at once, along with these additions to the pass file format:

• New keys specify the expiration date for a pass.

• You can specify that a pass is relevant only when it is in the vicinity of specific Bluetooth beacons.

• New attributes control how a pass is displayed. You can group passes together, display links with custom text on the back of a pass, and control how time values are displayed on the pass.

• You can now associate extra data with a pass. This data is available to your app but not displayed to the user.

• You can designate which data detectors to apply to the fields of your passes.

For information about how to use Pass Kit in your app, see Passbook Programming Guide. For information about the pass file format, see Passbook Package Format Reference.

OpenGL ES

OpenGL ES includes the following new extensions:

• The EXT_sRGB extension adds support for sRGB framebuffer operations.

• The GL_APPLE_pvrtc_sRGB extension adds support for sRGB texture data compressed in the PVRTC texture format.

• The GL_APPLE_draw_instanced and GL_APPLE_instanced_arrays extensions can improve rendering performance when your app draws multiple instances of the same object. You use a single call to draw instances of the same object. You add variation to each instance by specifying how fast each vertex attribute advances or by referencing an ID for each instance in your shader.

As always, check for the existence of an extension before using it in your app.

Also, textures can now be accessed in vertex shaders; query the value of the MAX_VERTEX_TEXTURE_IMAGE_UNITS attribute to determine the exact number of textures you can access.

MessageUI Framework

In the MessageUI framework, the MFMessageComposeViewController class adds support for attaching files to messages. For information about the new interfaces, see the framework header files.

For information about the classes of this framework, see Message UI Framework Reference.

Media Player Framework

In the Media Player framework, the MPVolumeView class provides support for determining whether wireless routes such as AirPlay and Bluetooth are available for the user to select. You can also determine whether one of these wireless routes is currently active. For information about the new interfaces, see the framework header files. For information about the classes of Media Player framework, see Media Player Framework Reference.

Map Kit Framework

The Map Kit framework (MapKit.framework) includes changes that are described in “Maps.”

For information about the classes of this framework, see Map Kit Framework Reference.

Image I/O Framework

The Image I/O framework (ImageIO.framework) now has interfaces for getting and setting image metadata.

For information about the new interfaces, see the framework header files. For information about the classes of this framework, see Image I/O Reference Collection.

iAd Framework

The iAd framework (iAd.framework) includes two extensions to other frameworks that make it easier to incorporate ads into your app’s content:

• The framework introduces new methods on the MPMoviePlayerController class that let you run ads before a movie.

• The framework extends the UIViewController class to make it easier to create ad-supported content. You can now configure your view controllers to display ads before displaying the actual content they manage.

For information about the new interfaces, see the framework header files. For information about the classes of this framework, see Ad Support Framework Reference.

Game Kit Framework

The Game Kit framework (GameKit.framework) includes numerous changes, which are described in “Game Center Improvements.”

For information about the classes of this framework, see Game Kit Framework Reference.

Foundation Framework

The Foundation framework (Foundation.framework) includes the following enhancements:

• The NSURLSession class is a new class for managing the acquisition of network-based resources in the background. This class serves as a replacement for theNSURLConnection class and its delegate; it also replaces the NSURLDownload class and its delegate.

• The NSURLComponents class is a new class for parsing the components of a URL. This class supports the URI standard (rfc3986/STD66) for parsing URLs.

• The NSNetService and NSNetServiceBrowser classes support peer-to-peer discovery over Bluetooth and Wi-Fi.

• The NSURLCredential and NSURLCredentialStorage classes let you create credentials with a synchronizable policy and provide the option of removing credentials with a synchronizable policy from iCloud.

• The NSURLCache, NSURLCredentialStorage, NSHTTPCookieStorage classes now support for the asynchronous processing of storage requests.

• The NSCalendar class supports new calendar types.

For information about the new interfaces, see the framework header files and Foundation release notes. For general information about the classes of this framework, see Foundation Framework Reference.

Core Telephony Framework

The Core Telephony framework (CoreTelephony.framework) lets you get information about the type of radio technology in use by the device, the current signal strength, and the cell ID serving the device. Apps developed in conjunction with a carrier can also authenticate their apps against a particular subscriber for that carrier.

For information about the new interfaces, see the framework header files. For general information about the classes of the Core Telephony framework, see Core Telephony Framework Reference

Core Motion Framework

The Core Motion framework (CoreMotion.framework) adds support for step counting and motion tracking. With step counting, the framework detects movements that correspond to user motion and uses that information to report the number of steps to your app. Because the system detects the motion, the system can continue to gather step data even when your app is not running. Alongside this feature, the framework can also distinguish different types of motion, including different motions reflective of travel by walking, by running, or by automobile. Navigation apps might use that data to change the type of directions they give to users.

For information about the new interfaces, see the framework header files. For general information about the classes of this framework, see Core Motion Framework Reference.

Core Location Framework

The Core Location framework (CoreLocation.framework) supports ranging using Bluetooth devices. Ranging lets you determine the relative range of nearby Bluetooth devices and respond appropriately. For example, a museum might place Bluetooth beacons in its galleries and provide visitors with an app that displays information as the user enters and exits those galleries. The framework also supports deferring the delivery of location updates until a specific time has elapsed or the user has moved a minimum distance.

For general information about the classes of this framework, see Core Location Framework Reference.

Core Foundation Framework

The Core Foundation framework (CoreFoundation.framework) now supports scheduling stream objects on dispatch queues. For information about the new interfaces, see the framework header files.

For general information about the interfaces of this framework, see Core Foundation Framework Reference.

Core Bluetooth Framework

The Core Bluetooth framework (CoreBluetooth.framework) includes the following enhancements:

• The framework supports saving state information for central and peripheral objects and restoring that state at app launch time. You can use this feature to support long-term actions involving Bluetooth devices.

• The central and peripheral classes now use an NSUUID object to store unique identifiers.

• You can now retrieve peripheral objects from a central manager synchronously.

For information about the new interfaces, see the framework header files. For general information about the classes of this framework, see Core Bluetooth Framework Reference.

AV Foundation Framework

The AV Foundation framework (AVFoundation.framework) includes the following enhancements:

• The AVAudioSession class supports the following new behaviors:

  • Support for selecting the preferred audio input, including audio from built-in microphones

  • Support for multichannel input and output

• The AVVideoCompositing and related classes let you support custom video compositors.

• The AVSpeechSynthesizer and related classes provide speech synthesis capabilities.

• The capture classes add support and interfaces for the following features:

  • Discovery of a camera’s supported formats

  • Support for 60 fps recording

  • Video zoom (true and digital) in recordings and video preview, including custom ramping

  • Real-time discovery of machine-readable barcode metadata

  • Autofocus range restriction

  • Access to the clocks used during capture

• There are new metadata key spaces for supported ISO formats such as MPEG-4 and 3GPP and improved support for filtering metadata items when copying those items from source assets to output files using the AVAssetExportSession class.

• The AVAssetWriter class provides assistance in formulating output settings and there are new level constants for H.264 encoding.

• The AVPlayerLayer class adds the videoRect property, which you can use to get the size and position of the video image.

• The AVPlayerItem class supports the following changes:

  • Asset properties can be loaded automatically when AVPlayerItem objects are prepared for playback.

  • When you link your app against iOS SDK 7, the behavior when getting the values of player item properties—such as the duration, or tracks, orpresentationSize properties—is different than pervious versions of iOS. The properties of this class now return a default value and no longer block your app if the AVPlayerItem object is is not yet ready to play. As soon as the player item’s status changes to AVPlayerItemStatusReadyToPlay, the getters reflect the actual values of the underlying media resource. If you use key-value observing to monitor changes to the properties, your observers are notified as soon as changes are available.

• The AVPlayerItemLegibleOutput class can process timed text from media files.

• The AVAssetResourceLoadingDelegate protocol now supports loading of arbitrary ranges of bytes from a media resource.

For information about the new interfaces, see the framework header files. For general information about the classes of this framework, see AV Foundation Framework Reference.

Accelerate Framework

The Accelerate framework (Accelerate.framework) includes the following enhancements:

• Improved support for manipulating Core Graphics data types

• Support for working with grayscale images of 1, 2, or 4 bits per pixel

• New routines for converting images between different formats and transforming image contents

• Support for biquad (IIR) operations

For information about the new interfaces, see the framework header files. For general information about the functions and types of this framework, see Accelerate Framework Reference.