GCD定时器实现动态检测

(void) timer{
dispatch_queue_t quque = dispatch_queue_create("myQ", 0);
dispatch_source_t timer=dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, quque);

uint64_t interval = 1 * NSEC_PER_SEC; // 时间间隔1秒

dispatch_source_set_timer(timer, dispatch_time(0.8, 0), interval, 0); // 延迟0.8秒执行

dispatch_source_set_event_handler(timer, ^{

  switch (self.Searchflag) {
      case 0:{
          YYLog(@"启动")
          
          break;
      }
      case 1:{
          
          dispatch_sync(dispatch_get_main_queue(), ^{
              [_searchRedRubineView stopSearchAnimation:^{
                  
                  _searchRedRubineView.failSearch = YES;
              }];
              
              dispatch_source_cancel(timer);
          });
          
         
          break;
      }
      case 2:{
          YYLog(@"搜索完毕")
          // 关闭
          dispatch_suspend(timer);
          
          YYLog(@"%@",timer)
          break;
      }
      default:
          break;
  }

});

dispatch_source_set_cancel_handler(timer, ^{
self.Searchflag = 0;
NSLog(@"cancel");
});

dispatch_resume(timer);