iOS Digest No. 6 (May 17 - May 30)

Less than a week remains before the Apple WWDC conference , let's see what expectations the developer community has and what events have occurred in the iOS development world over the past couple of weeks.

Industry news

• Heading "Ours at WWDC": 8 students from Russia are invited to the conference . They will be able to attend the event for free (recall, in addition, that the ticket, flight and accommodation costs tangible finances, you also need to participate in the lottery for the ticket) and take a picture with Tim Cook.
• Apple fuels public interest and creates a news feed by June 3. For example, the iPod Touch was updated for the first time in four years, while the design has not changed, basically only the processor and the price of the device have changed - the version with a pink body with 32GB on board in Russia can be bought for 18,990 rubles.
  Do you as mobile developers have to make iPod Touch support for their applications? Are you testing on this type of device? At the end of the article is a survey.
• MacBook Pro also caught up with the update . True, again, only the processor improved, and once again (already in the third!) They tried to solve the problems with the keyboard.
• Developers, as usual, wait for grand announcements and changes from the conference and share this on social networks: someone is waiting for a framework for a declarative UI, someone is in a Swift-like language instead of JavaScriptCore, and some are in Terminal and Xcode for the iPad :
  

  Let's start with this ^^ # wwdc19 Wishes
  
  - Declarative UI framework.
  - Or at least a fix for dynamic heights once and for all.
  - UIKit on Mac.

  - Alejandro Martinez (@ alexito4) April 6, 2019

  
  

  This is one of the few things that would get me standing on my feet cheering at WWDC. (Other options: reimagined Xcode extensions, Swift for WASM, and a Swift language equivalent of JavaScriptCore.) Https://t.co/aPJSPyWvO8

  - Paul Hudson (@twostraws) May 2, 2019

  
  What are your expectations from WWDC this year? What does the iOS developer lack for more comfortable programming? Share the pain in the comments.
  

  By the way, Paul Hudson, whose tweet is given above, is very familiar to us: he came to Moscow last year to Mobius conference and talked about how to write more secure code using Swift protocols, generics and extensions. Meanwhile, we held Mobius 2019 Piter last week - we will share the details in a separate post.

  
  
• It's no secret that some applications use the iOS capabilities in the background to send data about the device and users. A study is published with a list of companies whose applications send data at night without the knowledge of the user. In the comments, security users suggest switching to Android.

IOS Development News

• For faster removal of objects from CoreData, it is recommended to use NSBatchDeleteRequest, but be careful with it if your application has entities and delete rules are configured; several types of objects are deleted; non-SQLite storage under CoreData is used. Otherwise, you can get interesting artifacts in storage and crashes in runtime. See Using NSBatchDeleteRequest to delete batches in Core Data for more information .
• In addition to CoreData, we figure out how to properly store images for our entities (for example, miniature previews): next to other attributes like a BinaryData field or on a file system separately from the CoreData storage.
• In technical interviews, I often hear from candidates that you can forget and refuse to use @autoreleasepool in Swift. If your application suddenly creates UIImage or CoreData objects in a loop, then this is a potential memory leak, which can lead to the crash of the application during large iterations in the loop. You can deal with the principle of the authorization of pools after reading the article @autoreleasepool uses in 2019 Swift at https://swiftrocks.com .
• One of the most useful innovations in Swift 5.1 is the ability to find differences between the two collections out of the box, which will undoubtedly be convenient when updating the UITableView list so as not to overload the entire table or write your own code to search for changes between the two data arrays. An example of use is here .
• After you have learned how to correctly update the data list without a complete reboot in the previous paragraph, you must be able to beautifully show the user details by clicking on the list item. To do this, we deal with transitions between screens for cases when standard transition animations are not enough. A large series of articles in four parts will talk about this in more detail.
• Many novice developers are pushed away by learning the Swift language because of its apparent limited use (only for iOS development). But lately, Swift has been increasingly used to solve Machine Learning problems, as evidenced by convincing arguments in the article Why Swift May Be the Next Big Thing in Deep Learning .
• It’s also difficult to set autolayout constraints correctly, how to decide which way to turn the arrow on the UML class diagram in your mobile architecture. To fix this, we learn to solve problems with the constants without restarting the application .
• And finally: if you have already implemented all the features in your application and fixed all the bugs, pay attention to accessibility issues, this week there was a thread on Twitter on this topic with practical tips for those interested.