thin's Introduction

THIn

© 2013 James Montgomerie
[email protected], http://www.blog.montgomerie.net/
[email protected], http://th.ingsmadeoutofotherthin.gs/

What it is

Three easy ways to do things later in Cocoa/Cocoa Touch.
Simpler than dispatch_after, -performSelector:withObject:afterDelay: and NSTimer

How it works

Three ways! All call back on the main thread/runloop/dispatch queue.

A Category on NSObject defines a -thIn: method that takes an NSTimeInterval and returns a proxy object. Methods sent to it will be queued and sent to the original object after the interval elapses. The recently new instancetype return type makes this type-safe too!
```
[[self thIn:3] doYourThingWithThisArray:@[ @"Everybody", @"to", @"the", @"limit!" ]];
```
A Category on NSObject defines a -thIn:do: method that takes an NSTimeInterval and a block, and invokes the block after the interval elapses.
```
[self thIn:3 do:^(id obj) { 
    NSLog(@"The passed in object is the same as self. It's weakly held: %@", obj);
}];
```
THInWeakTimer is a lightweight timer. It has two main methods. -invalidate specifically cancels the timer. The timer is also implicitly cancelled if the THInWeakTimer is deallocated.
```
@interface THInWeakTimer : NSObject
- (id)initWithDelay:(NSTimeInterval)delay do:(void (^)(void))block;
- (void)invalidate;
@end
```

In the first two cases, the target object is weakly held. This means that if it is released before the interval is up the queued message/block will never be sent/invoked. Why? This is what made sense for my initial use case, and I still haven't found a case where I don't like the behaviour.

How to use it

I've packaged this as a static library, you should be able to use it as detailed in this blog post. It's only a couple of files though, so I won't tell anyone if you just copy them into your project instead.

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