WWDC Summary: developers need to know the new features of iOS 9 SDKWWDC 2015 Apple Developers Conference is an annual event mobile developers, InfoQ Chinese station in addition to the first time consolidation Keynote content for everyone to share, but also invited the senior tier developers to share their harvest. This article Wang Wei (onevcat) a summary of the WWDC revealed new features of iOS 9 SDK, to share to the majority of iOS developers. One year spent similar, each year is different. This year's WWDC always lively, thanks to Apple's random selection mechanism, this year there are more Chinese developers have the opportunity to visit the site to experience and get more exchanges and global developers. More developers may only pay attention to this global event Apple developers at home or long-distance company, but it also did not reduce the enthusiasm for the development of everyone. Life, there is more than learning. From WWDC began to receive attention since the majority of developers, this is an important way developers to learn and improve. You can feel the recent average level of domestic developers increasingly high hopes this trend will be maintained, after all, only with the support of the community, the developers will be the most powerful presence. Without further ado, let's look at this year's WWDC 2015 Latest Nike Shoes may require the developer to focus on some of the elements of it. Overview iOS biggest challenge and the most urgent task facing developers age 9 may have two aspects, first it is how to take advantage of and adapted the new iPad split-screen multitasking feature, followed by how to deal with and use to build native watchOS 2 Watch app. Also new are derived from the basic issues and the expansion of existing frameworks, including the extension from unit testing to UI testing, notification center, and the search page on how to further the occupation and use of the system, as well as the use of 2 or the like Swift. We can say that after iOS 7 and iOS 8 consecutive heavyweight change and renewal, for ordinary app developers, iOS 9 SDK attributed to ease slightly and calm, the new SDK did not happen in the API and the overall design Like the previous two systems that radical change. Developers are also able to take advantage of this opportunity to take a breather, to familiarize themselves with during the year and the transition to the use of at least iOS 8 SDK features to build your own app (for example, try to use the Size Class and Presentation Controller, etc.). Try to improve their ability and level of career making app and to ensure that Apple can keep the wheels rolling forward, it should be this year's Cocoa developers main task. In recent years, WWDC technology roadmap perspective, Apple development can be described as a chain, which a year if your technology stand still, then you want to catch up after that double effort may have to pay up. Multitasking iOS 9 It can be said that the biggest selling point. Multi-tasking features, especially split-screen multitasking makes iPad really become like a worthy task of PC. Although long ago already jailbreak iPad widget allows multiple programs to run simultaneously, but Apple is still very cautious until 2015 in his strongest performance of the mobile device mounting this function. iOS 9 multi task is divided into three forms, namely the temporary transfer out of the slide cover (Slide Over), video playback mode PIP (Picture in Picture) and really use both app split view ( Split View). Now the device can run iOS 9 in only the latest iPad Air 2 support split view mode, but I believe that with updated equipment, the use of split view mode is likely to become a mainstream daily use iPad way, so early preparation is Developers required homework. Although at first glance the feeling you want to support multitasking view would be a very complicated matter, but in fact if you keep up with Apple on the pace of the previous year, it is very simple. App will slide cover and split views using iOS 8 Size Class introduced the Compact Width and Regular Height setting, with the AutoLayout to lay. That is, if your app is before the iPhone and iPad universal, and have used a Size Class layout, basically you do not need to do anything Air Jordan 7 extra child has been able to support multi-tasking iOS 9 of the view. But if unfortunately you do not use these techniques, then perhaps you may need to move as quickly as possible to this layout in order to perfect support. Video app PIP model is relatively simple, or if you use AVPlayerViewController AVPlayerLayer to play the video, then do nothing would have been supported. But if you previously selected program is MPMoviePlayerController or MPMoviePlayerViewController, you may also need to migrate to the frame AVKit morning down, because in iOS 9 Media Player will be marked as deprecated and will not continue to maintain. watchOS 2 new watchOS in 2, Watch App architecture changed dramatically. Watch App the new system extension will not now exist in the iPhone, but will be installed directly into the watch to go, Apple Watch for equipment developers executable code from a simple interface to monitor evolution. Thanks to this, developers can also access the extension into the digital crown and like (though just very early visit, but better than nothing) heartbeat count such information. Although some progress, but in fact Apple in watchOS 2 years demonstrated the attitude is very cautious, this may be the first generation of Apple Watch equipment limitations of a great relationship, so in fact left to app developers the power and performance space is not very broad. But compared to the current WatchKit, it can be run from the iPhone itself is great progress. In order to communicate with the iPhone, now also added WatchConnectivity this new framework. We have every reason to look forward to Apple Watch and WatchKit performance in the next two to three years of. UI Test in the development field, the test Nike Basketball Shoes has been the key to ensure product quality. Since Xcode 4 from the test position in app development can be described as increasing every year. From the introduction of XCT framework to test target as the default when a new project, to join the last asynchronous code testing and performance testing. It can be said now testing framework that comes with Xcode has been able to meet the needs of most of the unit tests. But this is not enough. An iOS app developers always pay more attention to the work of UI and user experience, and unit testing simply can easily ensure that the correct model layer, it is difficult to make a difference in the UI. How to write an app UI testing has been one of the problems Cocoa community. Before then there like KIF, Automating, even FBSnapshotTestCase this brain-hole wide open programs. This year Apple gives a more attractive option, and that is Xcode comes XCUITest set of tools. And most of the existing UI testing tools similar, XCUI use markers to determine Accessibility view, but because it is Apple's own thing, it can automatically record your operation process, so you only need to write the last part of verification can be compared Many other convenient UI testing tools. Swift 2 Swift after a year of improvement and progress, now may well serve as app development work. I myself have been using Swift as the main language of daily work more than six months time, this half year, the overall feeling is that write more comfortable. Swift 2 main changes is the change in the error handling aspects, Apple NSError from Cocoa based on the traditional error handling into a throw catch of exception handling mechanism. This change can really make the program more secure, new ErrorType also very well be a unified description of the error. But after a day or two actual contact, grammatically feeling than the original process to write the code more. May be long habit of using NSError cause of it, it also was not able to fully accept the Swift 2 well in the exception mechanism. But this time Apple did relatively radical, the Cocoa API in error fully replaced by throw. So no matter the situation reluctantly, the transition to exception handling is Swift developer must face. Also like Apple added some new guard and defer such control flow keywords, it is also very practical in some other language features, which allow more streamlined Swift writing, to read more smoothly. In order to solve the problem of the availability of different SDK run-time, Apple is still avaliable Swift 2 added a block, before we need to remember their own API availability, and to do it by checking the system version and compare. Now, with avaliable detection, the compiler will check out the API calls that may arise version mismatch, app development of security has been further protected. In order to make the whole more suitable Swift SDK grammar habits, Apple finally introduces a generic in Objective-C in. This appears to be strengthening Objective-C, but in fact it is actually Swift dominate Apple developers open. With Objective-C generics later, with Swift Cocoa API access will no longer get AnyObject basic types, which makes the security features of Swift is also on the floor level. Finally, Swift 2 open messages. Swift compiler and standard library will open at the Nike Air Max 2012 end of this year, for the average app developers may not bring any changes, but it does mean that Swift will be making a special app transformation into a universal language language. Most likely to think that Swift-based back-end development, perhaps we will be able to feel before seeing the dominance of what Swift Javascript strength of the whole stack? App Thinning author working in Japan, because here we are a month and overflow traffic, so basically no one size on the app's mind, nothing more than download 5 seconds or 10 seconds of difference. But domestic peers, we found the size of the domestic app development for almost demanding requirements. Because the iOS app for Air Jordan 11 backwards compatibility, now contains both the 32 bit and 64 bit two slice. Also in the picture resources, it is readily available 1x 2x 3x image (1x Okay now be less need for a). And when the user app, because the device is specific, in fact, only one of a set of resources. But now purchase and download time is the whole app packages are downloaded. Air Jordan 13 Apple finally realized how silly this thing, iOS 9, finally can select only the required content (Slicing) download. This user is a big positive, because only need to upgrade to iOS 9, you can save a lot of traffic. For developers, there is not much to do, just use the asset catalog to manage material 2x 3x mark on it. App to another means of downsizing is to submit Bitcode to Apple, rather than the final binary. Bitcode is LLVM's intermediate code, the compiler updates, Apple can use Bitcode you previously submitted optimized so you do not update after the compiler to submit your app again, but Air Jordan 5 also to enjoy the improvements brought about by the compiler benefits. Bitcode support in the new project is enabled by default, there is no particular reason for it, you do not need it deliberately off. The final step is to load on demand resources. This may be a little more scenarios in the game. You can use the tag to organizations such as image or sound resources, such as mark them as level1, level2 so. Then start only need to download content level1, and in the course of play to go download level2. Or it can be passed to push this file download within those resources need to buy to get the. In some large game, which is very common optimization method, now in iOS 9 years can also easily use. Artificial intelligence and search API If this session WWDC Keynote what left me impressed with the content, I will give the phone more intelligent assistant cast a vote. Although it looks very basic, for example, is playing your favorite music into the headset, it is recommended you may contact people and open the app and so on, but it really is a step of great significance. Siri is now just a question answering system, if the context interrupted, \u0026 ldquo; She \u0026 rdquo; not even remember what the previous two sentences. Boss will not remember a secretary habits definitely not a good nurse, and Apple is giving iPhone these efforts. The good news is that we do not have to worry about yet come across deliberately not pass the Turing test machine, so there is a lot of space on the artificial intelligence can play. The search API essentially make app more than a possible entry. Some users will frequently use search interface, which is an excellent showcase your app and increase opportunities for open rates. If the app appropriate type, then it is well worth doing additional features. Game related games like app because in the different mobile platforms and user experience like no gap difference, it is most likely a cross-platform - after all, no matter which developers can ignore the share of Android. This is Apple's own SpriteKit and SceneKit this game framework has been tepid reasons. Than being confined to the Apple platform, more developers choose like Unity or Cocos2d-x such cross-platform solution. But this year Apple is continuing to strengthen the development of tools to support the game, including the state machine responsible for maintaining and routing, etc. GameplayKit framework, ReplayKit framework is responsible for recording and playback during the game, and the Model I / O framework for physical modeling. These are actually added some game industry has matured algorithms and tools in Apple game development system, developers save a lot of time. For individual developers homemade games, Apple's tool provides a relatively low threshold, easy to use. But now most of the game's developers will need cross-platform, always feel if Apple system can successfully go further observation. Other HomeKit, frame CloudKit, HealthKit etc. hodgepodge. If the app is iOS Only then do BaaS use CloudKit may be a good choice, but also the risk of future cross-platform data sharing difficult. Several other relatively strong professional framework, with the most need hardware support, in fact, been saying intelligent hardware is the next critical point, but at least until now not been able to burst a loud noise, the more it has entered the low-cost competition (bracelet or something you know), can only look forward to the follow-up performance of these devices say it. Finally, a just getting started or intend to join the Apple development in the welfare of friends. Now you may not need to join the paid developer program will be able to deploy the app on your device, and in the past this requires you $ 99 a year to join the developer program, at least, it can be said to be Apple further reduced barriers to development . Summary As mentioned above, the developer, this year's WWDC, and not as disruptive change for 13 years and 14 years, mostly to complement and strengthen the existing features of the development tool chain enhancements. This year can be said to be a good opportunity to Cocoa developers before precipitation knowledge, enhance their skills. Now WWDC 15 is still in full swing in progress. If you intend to embrace change as soon as the new SDK, please do not hesitate to visit Apple's developer site, to find topics of interest and watch it.