WWDC Notes

What's New in Cocoa Touch

Show Apple's description.
iOS 12 enhances the Cocoa Touch frameworks to improve app performance and deliver exciting new features. Learn about performance best practices, security improvements, tools for supporting multiple screen sizes and shapes, new APIs for iMessage apps, Siri Shortcuts, and Swift refinements. Find out which sessions you won't want to miss throughout the week.


cellForRow has:

  • 16ms to execute in a 60hz screen device
  • 8ms in a 120hz screen device

If the function takes longer than that, the app fps (and user experience) will drop.


From iOS 10 we have a prefetch data function (that runs in the background) which helps us fetching the data before it being required to be displayed in a cell:

Improvements Under The Hood

Beside the prefetching above, this session goes deep into a lot of system improvements (cpu, different threads management, auto layout).

Missing anything? Corrections? Contributions are welcome 😃


Written by


Federico Zanetello

Federico Zanetello is an iOS Engineer with strong passion for Swift, minimalism, and design. When he’s not busy automating things, he can be found writing at fivestars.blog and/or playing with the latest shiny toys.