Chapter 11: Using Timers, Threads, and Blocks
In This Chapter
Using NSTimer
Working with NSThread
Using NSOperation
Working with blocks and Grand Central Dispatch
Using NSTask
It's often useful to do many things at the same time. Cocoa offers a selection of classes and techniques for creating multiple simultaneous events and processes and for managing the relative and absolute timing of events. The newest classes use a new code idiom called blocks, which was introduced in OS X 10.6. Blocks can be used anywhere in an application, but Cocoa's event and data collection classes are being modified to support blocks where previously they used delegates and calls to other classes.
Using NSTimer
NSTimer is the simplest Cocoa event timing class. To trigger events at regular intervals, use:
NSTimer *theTimer = [NSTimer scheduledTimerWithTimeInterval: float
target: anObject
selector: @selector(theTimerMethod:)
userInfo: anOptionalObject
repeats: YES];
Implement the timer method in the target object:
-(void) theTimerMethod: (NSTimer *) theTimer {
//This code is called on every timer tick
}
To stop the timer, use
[myTimer invalidate];
The shortest possible interval is 0.0001s, but on ...
