GCD-Grand Central Dispatch

经常要用的,总结分类一下。

　　 //获得队列 DISPATCH_QUEUE_PRIORTY 优先级
    dispatch_queue_t Queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,);

    dispatch_queue_t MainQueue = dispatch_get_main_queue();

    //自定义Queue 第二参数默认串行(FIFO)  DISPATCH_QUEUE_CONCURRENT(可选,并发)
    dispatch_queue_t SelfQueue = dispatch_queue_create("COM.M1989.Queue", NULL);

    //dispatch_async
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,), ^{

        //Do Some?

    });

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,), ^{

        //耗时操作

         dispatch_async(dispatch_get_main_queue(), ^{

             //更新界面

         });

    });

    //dispatch_once_t 单例模式常用
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{

    });

    // dispatch_apply 并行,可利用CPU多核进行多线程操作 不过会阻塞当前线程,

    dispatch_apply(, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, ), ^(size_t y) {

        NSLog(@"123,%zu",y);

    });

    //觉得还是反正子线程比较好。如下
     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,), ^{

         dispatch_apply(, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, ), ^(size_t y) {

             NSLog(@"123,%zu",y);

         });

     });

    //dispatch_after 延迟执行,缺点不能临时取消,起码NSTimer 有个-(void)invalidate 能取消

    double Seconds = 10.0;

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t) (Seconds * NSEC_PER_SEC)), dispatch_get_main_queue(), ^(void){
        //延后10秒需要执行的代码
    });

    //dispatch_group_t 并行 group全部完成后发消息给notify，执行notify里block内容。 不阻塞当前线程。。。。
    dispatch_group_t groupQ = dispatch_group_create();

    dispatch_group_async(groupQ, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, ), ^{
        NSLog(@"");
    });

    dispatch_group_async(groupQ, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, ), ^{
        NSLog(@"");
    });

    dispatch_group_async(groupQ, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, ), ^{
        for(int i = ;i<;i++){
            NSLog(@"");
        }
    });

    dispatch_group_notify(groupQ, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, ), ^{

        NSLog(@"OK");

    });

    //dispatch_barrier_async  等待前面所有的任务执行完,并中断在此之后的任务。当前面的任务执行完后,此会执行,并恢复后面的任务。(试了,结果不理想)

    dispatch_barrier_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, ), ^{
        NSLog(@"barrier");
    });

未完待续。。。