GCD 定时器 dispatch_source_set_timer

dispatch_source_t   defaultTimer;///计时器

NSTimeInterval period = 1.0;

//创建队列

dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

_defaultTimer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);

dispatch_source_set_timer(_defaultTimer, dispatch_walltime(NULL, 0), period * NSEC_PER_SEC, 0);

__block NSInteger duration = defaultDuration;

dispatch_source_set_event_handler(_defaultTimer, ^{

dispatch_async(dispatch_get_main_queue(), ^{

if(duration==0)

{

dispatch_source_cancel(_defaultTimer);

[self remove];

}

duration--;

});

});

//取消队列

dispatch_source_set_cancel_handler(_defaultTimer, ^{

dispatch_release(_defaultTimer);

});

dispatch_resume(_defaultTimer);