子线程使用gcd起timer

NSLog(@"主线程 %@", [NSThread currentThread]);

//间隔还是2秒

uint64_t interval = 2 * NSEC_PER_SEC;

//创建一个专门执行timer回调的GCD队列

dispatch_queue_t queue = dispatch_queue_create("my queue", 0);

//创建Timer

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

//使用dispatch_source_set_timer函数设置timer参数

dispatch_source_set_timer(_timer, dispatch_time(DISPATCH_TIME_NOW, 0), interval, 0);

//设置回调

dispatch_source_set_event_handler(_timer, ^()

{

    NSLog(@"Timer %@", [NSThread currentThread]);

});

//dispatch_source默认是Suspended状态，通过dispatch_resume函数开始它

dispatch_resume(_timer);

关timer dispatch_suspend