5.13. Running Tasks Asynchronously with Operations
You want to execute operations concurrently.
Use operation queues. Alternatively, subclass
detach a new thread on the
As mentioned in Recipe 5.12, operations,
by default, run on the thread that calls the
start method. Usually we start operations on
the main thread, but at the same time we expect the operations to run
on their own threads and not take the main thread’s time slice. The
best solution for us would be to use operation queues. However, if you
want to manage your operations manually, which I do not recommend, you
NSOperation and detach
a new thread on the main method. Please refer to Recipe 5.16 for more information
about detached threads.
Let’s go ahead and use an operation queue and add two simple invocation operations to it. (For more information about invocation operations, please refer to this chapter’s Introduction. For additional example code on invocation operations, please refer to Recipe 5.12.) Here is the declaration (.h file) of the application delegate that utilizes an operation queue and two invocation operations:
#import <UIKit/UIKit.h> @interface Running_Tasks_Asynchronously_with_OperationsAppDelegate : UIResponder <UIApplicationDelegate> @property (nonatomic, strong) UIWindow *window; @property (nonatomic, strong) NSOperationQueue *operationQueue; @property (nonatomic, strong) NSInvocationOperation *firstOperation; @property (nonatomic, strong) ...