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Learn moreGrand Central Dispatch (GCD)
Free Course
Perform Asynchronous Operations in iOS
Estimated time
Approx. 2 Weeks
Skill level
Intermediate
Prerequisites
See prerequisites in detail
About this course
Many times your apps need to run lengthy operations in the background, like downloading data, but you don't want these operations to interfere with your UI.
Apple's GCD (long form: Grand Central Dispatch) framework allows you to create asynchronous apps for iOS, ensuring smooth a smooth user experience in situations like the one mentioned above.
What you will learn
Closures Reloaded
- Closures in Swift
- Properties of closures that we bypassed in our Swift Syntax course
Grand Central Dispatch
- Apple's open source library Grand Central Dispatch
- How GCD allows you to send tasks to the background and (equally important) to the foreground
- How and what you can send to the background and what must always run in the foreground
Sample App
- Create a simple App that downloads huge images (the easiest way to block the UI)
- Send this network lengthy task to the background in 2 different ways
- Run closures in the background
- Design methods that take a completion closure
Prerequisites and requirements
To be successful in this course, you should be comfortable programming in Swift, and understand closures. You can learn these skills in our Swift Syntax course.
Familiarity with The Hitchhiker's Guide to the Galaxy and The Matrix are also recommended in order to understand the jokes in this course.
See the Technology Requirements for using Udacity.
Why take this course?
Almsot all Apps consume data from web services, and therefore must use background threads for these lengthy operations.
Even though we provide a black box solution for concurrency in the iOS Networking with Swift course, it is important that you understand how concurrency works in iOS.
This knowledge is vital to deliver Apps that won't be rejected from the App Store and also provide a great user experience.
On top of that, GCD is a frequent topic in iOS job interviews.