MSWeakTimer)
CCWeakTimer (Microadjustment fromDescription
[Thread-safe NSTimer
drop-in alternative that doesn't retain the target and supports being used with GCD
queues.
Motivation
The first motivation for this class was to have a type of timer that objects could own and retain, without this creating a retain cycle ( like NSTimer
causes, since it retains its target ). This way you can just release the timer in the -dealloc
method of the object class that owns the timer.
The other problem when using NSTimer
is this note on the documentation:
Special Considerations
You must send this message from the thread on which the timer was installed. If you send this message from another thread, the input source associated with the timer may not be removed from its run loop, which could prevent the thread from exiting properly.
More often than not, an object needs to create a timer and invalidate it when a certain event occurs. However, doing this when that object works with a private GCD
queue gets tricky. This timer object is thread safe and doesn't have the notion of run loop, so it can be used with GCD
queues and installed / invalidated from any thread or queue.
Implementation
The implementation of CCWeakTimer
was reviewed and validated by a libdispatch
(GCD
) engineer at the WWDC 2013 Core OS Lab.
How to Use
Create an CCWeakTimer
object with this class method:
+ (CCWeakTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)timeInterval
target:(id)target
selector:(SEL)selector
userInfo:(id)userInfo
repeats:(BOOL)repeats
dispatchQueue:(dispatch_queue_t)dispatchQueue;
Check out the code in the sample app.
Installation
- Using CocoaPods:
Just add this line to your Podfile
:
pod 'CCWeakTimer'
- Manually:
Simply add the files CCWeakTimer.h
and CCWeakTimer.m
to your project.
Screenshots
Compatibility
- Requires ARC. If you want to use it in a project without ARC, mark
CCWeakTimer.m
with the linker flag-fobjc-arc
. - Supports iOS iOS8+ and Mac OSX 10.8+.
License
CCWeakTimer
is available under the MIT license. See the LICENSE file for more info.