#import "ViewController.h" @interface ViewController () @end /* GCD 核心概念：将任务添加队列，指定任务执行的方法 -任务 - 使用block 封装 - block 就是一个提前准备好的代码块，需要的时候执行 -队列 - 串行队列：一个接一个的执行任务 - 并发队列：可以同时调度多个任务 -任务执行函数（任务都需要在线程中执行） - 同步执行：不会到线程池里面去获取子线程 - 异步执行：只要有任务，就会去线程池取子线程（主队列除外） 小结： -- 开不开线程，取决于执行任务的函数，同步不开，异步就开 -- 开几条线程，取决于队列，串行开一条，并发开多条（异步） */ @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; } - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event { [self gcdDemo7]; } //全局队列 //Mark:全局队列(本质上是一个并发队列) -(void)gcdDemo7 { //全局队列 /* 参数 1：涉及系统适配 iOS 8.0 服务质量 QOS_CLASS_USER_INTERACTIVE 用户交互（希望线程快速执行，不要放一些耗时操作） QOS_CLASS_USER_INITIATED 用户需要的（不要放一些耗时操作） QOS_CLASS_DEFAULT 默认 QOS_CLASS_UTILITY 使用工具（用来耗时操作） QOS_CLASS_BACKGROUND 后台 QOS_CLASS_UNSPECIFIED 没有指定优先级 iOS 7.0 调度优先级 DISPATCH_QUEUE_PRIORITY_HIGH 高优先级 DISPATCH_QUEUE_PRIORITY_DEFAULT 0 默认优先级 DISPATCH_QUEUE_PRIORITY_LOW (-2) 低优先级 DISPATCH_QUEUE_PRIORITY_BACKGROUND 后台优先级 参数2：为未来的保留参数 提示：尤其不要选择BACKGROUND ，线程执行会慢到令人发指！ */ dispatch_queue_t q = dispatch_get_global_queue(0, 0);//前者:优先级 后者:保留值 for (int i = 0; i < 10; i++) { dispatch_async(q, ^{ // sync NSLog(@"%@ %d",[NSThread currentThread],i); }); } NSLog(@"Come here"); /* 2018-05-07 18:11:01.401836+0800 003 GCD演示[86602:5136701] Come here 2018-05-07 18:11:01.402103+0800 003 GCD演示[86602:5136760] <NSThread: 0x600000461b80>{number = 3, name = (null)} 0 2018-05-07 18:11:01.402121+0800 003 GCD演示[86602:5136759] <NSThread: 0x604000272f40>{number = 4, name = (null)} 1 2018-05-07 18:11:01.402156+0800 003 GCD演示[86602:5136761] <NSThread: 0x600000461f80>{number = 5, name = (null)} 2 2018-05-07 18:11:01.402204+0800 003 GCD演示[86602:5136768] <NSThread: 0x604000273000>{number = 6, name = (null)} 3 2018-05-07 18:11:01.402478+0800 003 GCD演示[86602:5136762] <NSThread: 0x604000273040>{number = 7, name = (null)} 4 2018-05-07 18:11:01.402593+0800 003 GCD演示[86602:5136821] <NSThread: 0x604000272f80>{number = 9, name = (null)} 6 2018-05-07 18:11:01.402610+0800 003 GCD演示[86602:5136820] <NSThread: 0x6000004620c0>{number = 8, name = (null)} 5 2018-05-07 18:11:01.402614+0800 003 GCD演示[86602:5136822] <NSThread: 0x6040002730c0>{number = 10, name = (null)} 7 2018-05-07 18:11:01.402693+0800 003 GCD演示[86602:5136823] <NSThread: 0x600000461bc0>{number = 11, name = (null)} 8 2018-05-07 18:11:01.402744+0800 003 GCD演示[86602:5136824] <NSThread: 0x604000273140>{number = 12, name = (null)} 9 ----> 总结:没什么特别的 开启一个 异步并发队列 2018-05-07 18:12:05.299154+0800 003 GCD演示[86627:5138620] <NSThread: 0x604000075f40>{number = 1, name = main} 0 2018-05-07 18:12:05.302814+0800 003 GCD演示[86627:5138620] <NSThread: 0x604000075f40>{number = 1, name = main} 1 2018-05-07 18:12:05.303830+0800 003 GCD演示[86627:5138620] <NSThread: 0x604000075f40>{number = 1, name = main} 2 2018-05-07 18:12:05.304140+0800 003 GCD演示[86627:5138620] <NSThread: 0x604000075f40>{number = 1, name = main} 3 2018-05-07 18:12:05.304293+0800 003 GCD演示[86627:5138620] <NSThread: 0x604000075f40>{number = 1, name = main} 4 2018-05-07 18:12:05.304410+0800 003 GCD演示[86627:5138620] <NSThread: 0x604000075f40>{number = 1, name = main} 5 2018-05-07 18:12:05.304639+0800 003 GCD演示[86627:5138620] <NSThread: 0x604000075f40>{number = 1, name = main} 6 2018-05-07 18:12:05.304751+0800 003 GCD演示[86627:5138620] <NSThread: 0x604000075f40>{number = 1, name = main} 7 2018-05-07 18:12:05.304915+0800 003 GCD演示[86627:5138620] <NSThread: 0x604000075f40>{number = 1, name = main} 8 2018-05-07 18:12:05.305030+0800 003 GCD演示[86627:5138620] <NSThread: 0x604000075f40>{number = 1, name = main} 9 2018-05-07 18:12:05.399105+0800 003 GCD演示[86627:5138620] Come here ----> 总结:没什么特别的 开启一个 同步并发队列 */ } //Mark:增加班同步任务 /* 队列调度多个任务之前，指定一个同步任务，让所有的异步任务，等待同步任务执行完成，就是依赖关系 同步任务就相当于一个锁 */ -(void)gcdDemo6 { // dispatch_queue_t loginQueue = dispatch_queue_create("CC_GCD", DISPATCH_QUEUE_CONCURRENT); dispatch_queue_t loginQueue = dispatch_queue_create("CC_GCD", NULL); void (^task)() = ^{ //1.登录 NSLog(@"用户登录了 %@",[NSThread currentThread]); //2.支付 sleep(1.3); NSLog(@"用户支付了 %@",[NSThread currentThread]); //3.下载 NSLog(@"用户下载了 %@",[NSThread currentThread]); /* 2018-05-07 17:50:52.713088+0800 003 GCD演示[86418:5118592] 用户登录了 <NSThread: 0x60400027b1c0>{number = 3, name = (null)} 2018-05-07 17:50:53.720881+0800 003 GCD演示[86418:5118592] 用户支付了 <NSThread: 0x60400027b1c0>{number = 3, name = (null)} 2018-05-07 17:50:53.721117+0800 003 GCD演示[86418:5118592] 用户下载了 <NSThread: 0x60400027b1c0>{number = 3, name = (null)} 总结:串行队列/并行队列 效果是一样的 */ }; dispatch_async(loginQueue, task); } //Mark 并发队列，同步执行 /* 会不会开辟线程？ 顺序执行吗？ comeHere 不会 顺序 最后 */ -(void)gcdDemo4 { //1.队列 DISPATCH_QUEUE_CONCURRENT dispatch_queue_t q = dispatch_queue_create("CC_GCD", DISPATCH_QUEUE_CONCURRENT); //2.同步执行任务 for (int i = 0; i < 10; i++) { NSLog(@"%d------------- ",i); dispatch_sync(q, ^{ if(i==3||i==5){ sleep(2.0); } NSLog(@"%@，%d",[NSThread currentThread],i); }); } NSLog(@"come here"); /* 2018-05-07 16:51:46.511757+0800 003 GCD演示[85767:5060291] 0------------- 2018-05-07 16:51:46.518181+0800 003 GCD演示[85767:5060291] <NSThread: 0x600000071e40>{number = 1, name = main}，0 2018-05-07 16:51:46.518790+0800 003 GCD演示[85767:5060291] 1------------- 2018-05-07 16:51:46.519115+0800 003 GCD演示[85767:5060291] <NSThread: 0x600000071e40>{number = 1, name = main}，1 2018-05-07 16:51:46.519493+0800 003 GCD演示[85767:5060291] 2------------- 2018-05-07 16:51:46.521978+0800 003 GCD演示[85767:5060291] <NSThread: 0x600000071e40>{number = 1, name = main}，2 2018-05-07 16:51:46.522231+0800 003 GCD演示[85767:5060291] 3------------- 2018-05-07 16:51:48.523538+0800 003 GCD演示[85767:5060291] <NSThread: 0x600000071e40>{number = 1, name = main}，3 2018-05-07 16:51:48.523810+0800 003 GCD演示[85767:5060291] 4------------- 2018-05-07 16:51:48.524136+0800 003 GCD演示[85767:5060291] <NSThread: 0x600000071e40>{number = 1, name = main}，4 2018-05-07 16:51:48.524444+0800 003 GCD演示[85767:5060291] 5------------- 2018-05-07 16:51:50.526239+0800 003 GCD演示[85767:5060291] <NSThread: 0x600000071e40>{number = 1, name = main}，5 2018-05-07 16:51:50.526510+0800 003 GCD演示[85767:5060291] 6------------- 2018-05-07 16:51:50.526741+0800 003 GCD演示[85767:5060291] <NSThread: 0x600000071e40>{number = 1, name = main}，6 2018-05-07 16:51:50.526947+0800 003 GCD演示[85767:5060291] 7------------- 2018-05-07 16:51:50.527393+0800 003 GCD演示[85767:5060291] <NSThread: 0x600000071e40>{number = 1, name = main}，7 2018-05-07 16:51:50.528577+0800 003 GCD演示[85767:5060291] 8------------- 2018-05-07 16:51:50.528809+0800 003 GCD演示[85767:5060291] <NSThread: 0x600000071e40>{number = 1, name = main}，8 2018-05-07 16:51:50.528969+0800 003 GCD演示[85767:5060291] 9------------- 2018-05-07 16:51:50.529213+0800 003 GCD演示[85767:5060291] <NSThread: 0x600000071e40>{number = 1, name = main}，9 2018-05-07 16:51:50.529396+0800 003 GCD演示[85767:5060291] come here 总结:由于同步执行,即使为异步队列,也不会开辟新线程, 任务在主线程内执行.顺序执行() 所以说开不开线程,看是否异步,和这个队列没毛关系 */ } //Mark：并发队列，异步执行 /* 会不会开辟线程？ 顺序执行吗？ comeHere 会 不是 不确定 */ -(void)gcdDemo3 { //1.队列 DISPATCH_QUEUE_CONCURRENT dispatch_queue_t q = dispatch_queue_create("CC_GCD", DISPATCH_QUEUE_CONCURRENT); //2.异步执行任务 for (int i = 0; i < 10; i++) { NSLog(@"%d------------- ",i); dispatch_async(q, ^{ if(i== 3||i==4){ sleep(1.5); } NSLog(@"%@，%d",[NSThread currentThread],i); }); } NSLog(@"come here"); /* 2018-05-07 16:47:48.030652+0800 003 GCD演示[85712:5053945] 0------------- 2018-05-07 16:47:48.030958+0800 003 GCD演示[85712:5053945] 1------------- 2018-05-07 16:47:48.031097+0800 003 GCD演示[85712:5054078] <NSThread: 0x600000471a80>{number = 3, name = (null)}，0 2018-05-07 16:47:48.031267+0800 003 GCD演示[85712:5053945] 2------------- 2018-05-07 16:47:48.031354+0800 003 GCD演示[85712:5054079] <NSThread: 0x600000472100>{number = 4, name = (null)}，1 2018-05-07 16:47:48.031461+0800 003 GCD演示[85712:5053945] 3------------- 2018-05-07 16:47:48.031501+0800 003 GCD演示[85712:5054078] <NSThread: 0x600000471a80>{number = 3, name = (null)}，2 2018-05-07 16:47:48.031620+0800 003 GCD演示[85712:5053945] 4------------- 2018-05-07 16:47:48.032760+0800 003 GCD演示[85712:5053945] 5------------- 2018-05-07 16:47:48.033992+0800 003 GCD演示[85712:5053945] 6------------- 2018-05-07 16:47:48.034114+0800 003 GCD演示[85712:5054077] <NSThread: 0x600000471ec0>{number = 5, name = (null)}，5 2018-05-07 16:47:48.035160+0800 003 GCD演示[85712:5053945] 7------------- 2018-05-07 16:47:48.035318+0800 003 GCD演示[85712:5054075] <NSThread: 0x604000262d00>{number = 6, name = (null)}，6 2018-05-07 16:47:48.037172+0800 003 GCD演示[85712:5053945] 8------------- 2018-05-07 16:47:48.037215+0800 003 GCD演示[85712:5054077] <NSThread: 0x600000471ec0>{number = 5, name = (null)}，7 2018-05-07 16:47:48.037922+0800 003 GCD演示[85712:5053945] 9------------- 2018-05-07 16:47:48.037965+0800 003 GCD演示[85712:5054075] <NSThread: 0x604000262d00>{number = 6, name = (null)}，8 2018-05-07 16:47:48.038402+0800 003 GCD演示[85712:5053945] come here 2018-05-07 16:47:48.038440+0800 003 GCD演示[85712:5054077] <NSThread: 0x600000471ec0>{number = 5, name = (null)}，9 2018-05-07 16:47:49.034294+0800 003 GCD演示[85712:5054079] <NSThread: 0x600000472100>{number = 4, name = (null)}，3 2018-05-07 16:47:49.034364+0800 003 GCD演示[85712:5054078] <NSThread: 0x600000471a80>{number = 3, name = (null)}，4 总结:并行队列/异步执行 是否开辟线程:会 开辟线程数:不一定/cpu调度 执行顺序:不一定,看线程内任务是否耗时 */ } //Mark：串行队列，异步执行 /* 会不会开辟线程？ 顺序执行吗？ 会 会 */ -(void)gcdDemo2 { //1.队列 -- 串行 DISPATCH_QUEUE_SERIAL 串行 等价于NULL dispatch_queue_t q = dispatch_queue_create("CC_GCD", NULL); //2.异步执行任务 for (int i = 0; i < 10; i++) { NSLog(@"%d------------- ",i); dispatch_async(q, ^{ NSLog(@"%@，%d",[NSThread currentThread],i); }); } NSLog(@"come here"); /* 2018-05-07 16:42:14.945286+0800 003 GCD演示[85624:5044961] 0------------- 2018-05-07 16:42:14.945568+0800 003 GCD演示[85624:5044961] 1------------- 2018-05-07 16:42:14.945730+0800 003 GCD演示[85624:5045326] <NSThread: 0x60400026f300>{number = 3, name = (null)}，0 2018-05-07 16:42:14.946207+0800 003 GCD演示[85624:5044961] 2------------- 2018-05-07 16:42:14.946371+0800 003 GCD演示[85624:5045326] <NSThread: 0x60400026f300>{number = 3, name = (null)}，1 2018-05-07 16:42:14.946510+0800 003 GCD演示[85624:5044961] 3------------- 2018-05-07 16:42:14.946642+0800 003 GCD演示[85624:5044961] 4------------- 2018-05-07 16:42:14.946673+0800 003 GCD演示[85624:5045326] <NSThread: 0x60400026f300>{number = 3, name = (null)}，2 2018-05-07 16:42:14.947064+0800 003 GCD演示[85624:5044961] 5------------- 2018-05-07 16:42:14.948015+0800 003 GCD演示[85624:5045326] <NSThread: 0x60400026f300>{number = 3, name = (null)}，3 2018-05-07 16:42:14.948690+0800 003 GCD演示[85624:5044961] 6------------- 2018-05-07 16:42:14.949690+0800 003 GCD演示[85624:5045326] <NSThread: 0x60400026f300>{number = 3, name = (null)}，4 2018-05-07 16:42:14.950768+0800 003 GCD演示[85624:5044961] 7------------- 2018-05-07 16:42:14.951341+0800 003 GCD演示[85624:5045326] <NSThread: 0x60400026f300>{number = 3, name = (null)}，5 2018-05-07 16:42:14.951730+0800 003 GCD演示[85624:5044961] 8------------- 2018-05-07 16:42:14.952629+0800 003 GCD演示[85624:5045326] <NSThread: 0x60400026f300>{number = 3, name = (null)}，6 2018-05-07 16:42:14.953559+0800 003 GCD演示[85624:5044961] 9------------- 2018-05-07 16:42:14.954518+0800 003 GCD演示[85624:5045326] <NSThread: 0x60400026f300>{number = 3, name = (null)}，7 2018-05-07 16:42:14.955275+0800 003 GCD演示[85624:5044961] come here 2018-05-07 16:42:14.955690+0800 003 GCD演示[85624:5045326] <NSThread: 0x60400026f300>{number = 3, name = (null)}，8 2018-05-07 16:42:14.956065+0800 003 GCD演示[85624:5045326] <NSThread: 0x60400026f300>{number = 3, name = (null)}，9 总结:异步串行队列,会开辟子线程,然后子线程内任务依次执行(废话 一个线程内执行的 能不顺序执行么) come here 虽然在主线程,但是不见得先打印,也许子线程中任务执行更快 */ } //Mark:串行队列，同步执行 /* 会不会开辟线程？ 顺序执行吗？ 不会 会 */ -(void)gcdDemo1 { //1.队列 -- 串行 DISPATCH_QUEUE_SERIAL 串行 等价于NULL dispatch_queue_t q = dispatch_queue_create("CC_GCD", NULL); //2.同步执行任务 for (int i = 0; i < 10; i++) { dispatch_sync(q, ^{ NSLog(@"%@，%d",[NSThread currentThread],i); }); } /* 2018-05-07 16:40:25.967160+0800 003 GCD演示[85590:5041711] <NSThread: 0x6000002600c0>{number = 1, name = main}，0 2018-05-07 16:40:25.969158+0800 003 GCD演示[85590:5041711] <NSThread: 0x6000002600c0>{number = 1, name = main}，1 2018-05-07 16:40:25.987708+0800 003 GCD演示[85590:5041711] <NSThread: 0x6000002600c0>{number = 1, name = main}，2 2018-05-07 16:40:25.988432+0800 003 GCD演示[85590:5041711] <NSThread: 0x6000002600c0>{number = 1, name = main}，3 2018-05-07 16:40:25.989809+0800 003 GCD演示[85590:5041711] <NSThread: 0x6000002600c0>{number = 1, name = main}，4 2018-05-07 16:40:25.990379+0800 003 GCD演示[85590:5041711] <NSThread: 0x6000002600c0>{number = 1, name = main}，5 2018-05-07 16:40:25.990513+0800 003 GCD演示[85590:5041711] <NSThread: 0x6000002600c0>{number = 1, name = main}，6 2018-05-07 16:40:25.990759+0800 003 GCD演示[85590:5041711] <NSThread: 0x6000002600c0>{number = 1, name = main}，7 2018-05-07 16:40:25.990905+0800 003 GCD演示[85590:5041711] <NSThread: 0x6000002600c0>{number = 1, name = main}，8 2018-05-07 16:40:25.991057+0800 003 GCD演示[85590:5041711] <NSThread: 0x6000002600c0>{number = 1, name = main}，9 总结:没啥好说的 同步串行队列 ,主线线程内依次执行 */ } //线程池???? !!! //全局队列本质是一个 并发队列 /*gcd 执行子线程的执行顺序 方案1: 实现一个异步串行队列 异步开启子线程,串行队列顺序执行 三个任务 方案2:将三个任务封装成一个block整体 开启异步队列/串行,并行队列都行,因为是个整体 */ @end