Mastering Swift 2 Programming (Video 38)

This video tutorial explains how to use dispatch groups in Grand Central Dispatch (GCD) to manage asynchronous tasks in iOS applications. It covers creating a simple Xcode project, implementing time-consuming tasks on background queues, and using dispatch groups to ensure tasks complete before proceeding. The tutorial also discusses the use of dispatch group enter and leave to manage task execution and introduces dispatch group notify as an alternative to blocking threads. The video concludes with a brief overview of concurrent work using NS thread and NS operation queue.

What is the primary purpose of using dispatch groups in Grand Central Dispatch?

• To handle user input

• To wait for asynchronous tasks to complete

• To manage memory allocation

• To create new threads

In the simple application, what is the purpose of the 'time consuming task' function?

• To handle user interface updates

• To manage network requests

• To emulate a time-consuming task

• To perform a quick calculation

Why should dispatch groups be used on a custom queue rather than the main queue?

• To prevent blocking the main thread

• To enhance security

• To improve application speed

• To reduce memory usage

What function is used to indicate that a task in a dispatch group has started?

• dispatch_group_notify

• dispatch_group_wait

• dispatch_group_leave

• dispatch_group_enter

What is the advantage of using dispatch group notify over dispatch group wait?

• It uses less memory

• It is faster

• It avoids blocking threads

• It is easier to implement

Which method is used to execute code after a dispatch group task is completed without blocking a thread?

• dispatch_group_wait

• dispatch_group_notify

• dispatch_group_enter

• dispatch_group_leave

What is Grand Central Dispatch primarily used for in applications?

• Managing user interfaces

• Handling network requests

• Performing concurrent tasks

• Storing data