disptch_after 自递归

NSArray *arr = @[@"1", @"2", @"3", @"4", @"5"];

    int time = 1;//间隔时间s

    for (int i = 0; i < arr.count; i++) {

        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(i * time * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

            //循环里执行的语句

            NSLog(@"%@",arr);
        });

    }