1-创建、获取队列
主要测试
1.dispatch_queue_create
2.dispatch_sync
3.dispatch_async
4.dispatch_get_main_queue
5.dispatch_get_global_queue
//
// ViewController.m
// GCDDemo
//
// Created by gongzixiaobai on 16/3/19.
// Copyright ? 2016年 公子小白. All rights reserved.
//
#import "ViewController.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
[self gcdTest7];
}
#pragma mark - GCD API 测试
// step1 ：测试dispatch_queue_create和dispatch_async
/**************************************************step1-start*************************************************************/
/*
测试总结：
*任务提交方式(sync、async)和队列的属性(DISPATCH_QUEUE_SERIAL、DISPATCH_QUEUE_CONCURRENT)对任务执行(顺序和所在线程)的影响
只要队列中有任务就会立即执行，
a)sync 方式提交的会立即在当前线程执行(会阻塞当前线程，与当前线程间有先后顺序)，
b)async 方式提交的会在其它线程执行(具体开多少条线程由GCD系统管理)并与当前线程并发执行(与当前线程没有先后顺序)
c)DISPATCH_QUEUE_SERIAL决定了队列中的任务只能顺序执行(不论用sync还是async方式提交)
d)DISPATCH_QUEUE_CONCURRENT决定了队列中的任务可以顺序执行(sync方式提交)也可以乱序执行(async方式提交)
e)串行队列最多只会创建一个线程(用async提交)并行队列可以创建多个具体由GCD系统决定(用async提交)
*/
//- (void)gcdTest4
//{
// //1. 并行队列
// dispatch_queue_t queue = dispatch_queue_create("xiaobai", DISPATCH_QUEUE_CONCURRENT);
//
// // 2. 异步执行任务
// for (int i = 0; i < 10; i++) {
// dispatch_async(queue, ^{
// NSLog(@"%@ %d", [NSThread currentThread], i);
// });
// }
//
//
// NSLog(@"========");
// /*
// 2016-03-19 14:54:17.727 GCDDemo[9112:751722] ========
// 2016-03-19 14:54:17.728 GCDDemo[9112:759447] <NSThread: 0x7f934a458700>{number = 26, name = (null)} 0
// 2016-03-19 14:54:17.728 GCDDemo[9112:759445] <NSThread: 0x7f934a51da60>{number = 27, name = (null)} 1
// 2016-03-19 14:54:17.728 GCDDemo[9112:759453] <NSThread: 0x7f934a4ad580>{number = 28, name = (null)} 2
// 2016-03-19 14:54:17.728 GCDDemo[9112:759454] <NSThread: 0x7f934a43e390>{number = 29, name = (null)} 3
// 2016-03-19 14:54:17.728 GCDDemo[9112:759447] <NSThread: 0x7f934a458700>{number = 26, name = (null)} 4
// 2016-03-19 14:54:17.729 GCDDemo[9112:759456] <NSThread: 0x7f934a50fd20>{number = 30, name = (null)} 5
// 2016-03-19 14:54:17.729 GCDDemo[9112:759445] <NSThread: 0x7f934a51da60>{number = 27, name = (null)} 6
// 2016-03-19 14:54:17.729 GCDDemo[9112:759458] <NSThread: 0x7f934a5083e0>{number = 31, name = (null)} 7
// 2016-03-19 14:54:17.729 GCDDemo[9112:759460] <NSThread: 0x7f934a520110>{number = 32, name = (null)} 8
// 2016-03-19 14:54:17.730 GCDDemo[9112:759453] <NSThread: 0x7f934a4ad580>{number = 28, name = (null)} 9
//
// 2016-03-19 14:54:23.083 GCDDemo[9112:760048] <NSThread: 0x7f934a51da60>{number = 34, name = (null)} 1
// 2016-03-19 14:54:23.083 GCDDemo[9112:760044] <NSThread: 0x7f934a507430>{number = 33, name = (null)} 0
// 2016-03-19 14:54:23.083 GCDDemo[9112:760046] <NSThread: 0x7f934a703160>{number = 35, name = (null)} 2
// 2016-03-19 14:54:23.083 GCDDemo[9112:760054] <NSThread: 0x7f934a50fd20>{number = 36, name = (null)} 3
// 2016-03-19 14:54:23.084 GCDDemo[9112:760048] <NSThread: 0x7f934a51da60>{number = 34, name = (null)} 4
// 2016-03-19 14:54:23.083 GCDDemo[9112:751722] ========
// 2016-03-19 14:54:23.084 GCDDemo[9112:760044] <NSThread: 0x7f934a507430>{number = 33, name = (null)} 5
// 2016-03-19 14:54:23.084 GCDDemo[9112:760046] <NSThread: 0x7f934a703160>{number = 35, name = (null)} 6
// 2016-03-19 14:54:23.084 GCDDemo[9112:760054] <NSThread: 0x7f934a50fd20>{number = 36, name = (null)} 7
// 2016-03-19 14:54:23.084 GCDDemo[9112:760048] <NSThread: 0x7f934a51da60>{number = 34, name = (null)} 8
// 2016-03-19 14:54:23.084 GCDDemo[9112:760044] <NSThread: 0x7f934a507430>{number = 33, name = (null)} 9
//
//
//
// */
//
//}
//-(void)gcdTest3
//{
//
// dispatch_queue_t aqueue = dispatch_queue_create("test", DISPATCH_QUEUE_CONCURRENT);
// for (int i = 0; i<10; i++) {
// dispatch_sync(aqueue, ^{
// NSLog(@"%@,%d",[NSThread currentThread],i);
// });
// }
//
// NSLog(@"=======");
// /*
// 2016-03-19 14:51:14.429 GCDDemo[8943:734337] <NSThread: 0x7fa6a0e02ac0>{number = 1, name = main},0
// 2016-03-19 14:51:14.430 GCDDemo[8943:734337] <NSThread: 0x7fa6a0e02ac0>{number = 1, name = main},1
// 2016-03-19 14:51:14.430 GCDDemo[8943:734337] <NSThread: 0x7fa6a0e02ac0>{number = 1, name = main},2
// 2016-03-19 14:51:14.430 GCDDemo[8943:734337] <NSThread: 0x7fa6a0e02ac0>{number = 1, name = main},3
// 2016-03-19 14:51:14.430 GCDDemo[8943:734337] <NSThread: 0x7fa6a0e02ac0>{number = 1, name = main},4
// 2016-03-19 14:51:14.430 GCDDemo[8943:734337] <NSThread: 0x7fa6a0e02ac0>{number = 1, name = main},5
// 2016-03-19 14:51:14.430 GCDDemo[8943:734337] <NSThread: 0x7fa6a0e02ac0>{number = 1, name = main},6
// 2016-03-19 14:51:14.431 GCDDemo[8943:734337] <NSThread: 0x7fa6a0e02ac0>{number = 1, name = main},7
// 2016-03-19 14:51:14.431 GCDDemo[8943:734337] <NSThread: 0x7fa6a0e02ac0>{number = 1, name = main},8
// 2016-03-19 14:51:14.431 GCDDemo[8943:734337] <NSThread: 0x7fa6a0e02ac0>{number = 1, name = main},9
// 2016-03-19 14:51:14.431 GCDDemo[8943:734337] =======
//
//
// */
//}
//-(void)gcdTest2
//{
//
// dispatch_queue_t aqueue = dispatch_queue_create("test", DISPATCH_QUEUE_SERIAL);
// for (int i = 0; i<10; i++) {
// dispatch_async(aqueue, ^{
// NSLog(@"%@,%d",[NSThread currentThread],i);
// });
// }
//
// NSLog(@"=======");
// /*
//
// 2016-03-19 14:45:50.022 GCDDemo[8603:695116] =======
// 2016-03-19 14:45:50.022 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},0
// 2016-03-19 14:45:50.023 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},1
// 2016-03-19 14:45:50.023 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},2
// 2016-03-19 14:45:50.024 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},3
// 2016-03-19 14:45:50.024 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},4
// 2016-03-19 14:45:50.024 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},5
// 2016-03-19 14:45:50.024 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},6
// 2016-03-19 14:45:50.025 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},7
// 2016-03-19 14:45:50.025 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},8
// 2016-03-19 14:45:50.025 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},9
//
// 2016-03-19 14:45:50.191 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},0
// 2016-03-19 14:45:50.192 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},1
// 2016-03-19 14:45:50.192 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},2
// 2016-03-19 14:45:50.191 GCDDemo[8603:695116] =======
// 2016-03-19 14:45:50.192 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},3
// 2016-03-19 14:45:50.192 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},4
// 2016-03-19 14:45:50.193 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},5
// 2016-03-19 14:45:50.193 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},6
// 2016-03-19 14:45:50.193 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},7
// 2016-03-19 14:45:50.194 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},8
// 2016-03-19 14:45:50.194 GCDDemo[8603:699491] <NSThread: 0x7fe6e1e283d0>{number = 4, name = (null)},9
//
// */
//
//}
//-(void)gcdTest1
//{
//
// dispatch_queue_t aqueue = dispatch_queue_create("test", DISPATCH_QUEUE_SERIAL);
// for (int i = 0; i<10; i++) {
// dispatch_sync(aqueue, ^{
// NSLog(@"%@,%d",[NSThread currentThread],i);
// });
// }
//
// NSLog(@"=======");
// /*
//
// dispatch_sync提交的任务会阻塞当前任务，它会先执行，完了再向下执行
//
//
// 2016-03-19 14:21:13.531 GCDDemo[7089:575399] <NSThread: 0x7febd1f03530>{number = 1, name = main},0
// 2016-03-19 14:21:13.532 GCDDemo[7089:575399] <NSThread: 0x7febd1f03530>{number = 1, name = main},1
// 2016-03-19 14:21:13.532 GCDDemo[7089:575399] <NSThread: 0x7febd1f03530>{number = 1, name = main},2
// 2016-03-19 14:21:13.532 GCDDemo[7089:575399] <NSThread: 0x7febd1f03530>{number = 1, name = main},3
// 2016-03-19 14:21:13.532 GCDDemo[7089:575399] <NSThread: 0x7febd1f03530>{number = 1, name = main},4
// 2016-03-19 14:21:13.533 GCDDemo[7089:575399] <NSThread: 0x7febd1f03530>{number = 1, name = main},5
// 2016-03-19 14:21:13.533 GCDDemo[7089:575399] <NSThread: 0x7febd1f03530>{number = 1, name = main},6
// 2016-03-19 14:21:13.533 GCDDemo[7089:575399] <NSThread: 0x7febd1f03530>{number = 1, name = main},7
// 2016-03-19 14:21:13.533 GCDDemo[7089:575399] <NSThread: 0x7febd1f03530>{number = 1, name = main},8
// 2016-03-19 14:21:13.533 GCDDemo[7089:575399] <NSThread: 0x7febd1f03530>{number = 1, name = main},9
// 2016-03-19 14:21:13.533 GCDDemo[7089:575399] =======
//
// */
//
//}
/**************************************************step1-end*************************************************************/
// step2 ：测试dispatch_get_main_queue();、dispatch_get_global_queue
/*
总结：
全局队列 跟 并发队列的 区别
1. 全局队列没有名称 并发队列有名称
2. 全局队列，是供所有的应用程序共享。
3. 在MRC开发，并发队列，创建完了，需要释放。 全局队列不需要我们管理
*/
/**************************************************step2-start*************************************************************/
/**
* sync提交任务到主队列会发生死锁，async提交任务到主队列会等主线程中任务处理完在执行提交的任务
*/
- (void)gcdTest5
{
// 1. 获得主队列-> 程序启动，--> 至少有一个主线程-> 一开始就会创建主队列
dispatch_queue_t queue = dispatch_get_main_queue();
NSLog(@"1----");
// 2. 异步执行任务
for (int i = 0; i < 10; i++) {
NSLog(@"调度前---");
// 异步：把任务放到主队列里，但是不需要马上执行
dispatch_async(queue, ^{
NSLog(@"%@ %d", [NSThread currentThread], i);
});
NSLog(@"睡会");
[NSThread sleepForTimeInterval:2.0];
}
NSLog(@"完成----");
/*
2016-03-19 16:46:10.151 GCDDemo[15481:1177084] 1----
2016-03-19 16:46:10.151 GCDDemo[15481:1177084] 调度前---
2016-03-19 16:46:10.152 GCDDemo[15481:1177084] 睡会
2016-03-19 16:46:12.152 GCDDemo[15481:1177084] 调度前---
2016-03-19 16:46:12.153 GCDDemo[15481:1177084] 睡会
2016-03-19 16:46:14.153 GCDDemo[15481:1177084] 调度前---
2016-03-19 16:46:14.154 GCDDemo[15481:1177084] 睡会
2016-03-19 16:46:16.155 GCDDemo[15481:1177084] 调度前---
2016-03-19 16:46:16.155 GCDDemo[15481:1177084] 睡会
2016-03-19 16:46:18.156 GCDDemo[15481:1177084] 调度前---
2016-03-19 16:46:18.157 GCDDemo[15481:1177084] 睡会
2016-03-19 16:46:20.157 GCDDemo[15481:1177084] 调度前---
2016-03-19 16:46:20.157 GCDDemo[15481:1177084] 睡会
2016-03-19 16:46:22.158 GCDDemo[15481:1177084] 调度前---
2016-03-19 16:46:22.159 GCDDemo[15481:1177084] 睡会
2016-03-19 16:46:24.160 GCDDemo[15481:1177084] 调度前---
2016-03-19 16:46:24.160 GCDDemo[15481:1177084] 睡会
2016-03-19 16:46:26.161 GCDDemo[15481:1177084] 调度前---
2016-03-19 16:46:26.162 GCDDemo[15481:1177084] 睡会
2016-03-19 16:46:28.163 GCDDemo[15481:1177084] 调度前---
2016-03-19 16:46:28.164 GCDDemo[15481:1177084] 睡会
2016-03-19 16:46:30.165 GCDDemo[15481:1177084] 完成----
2016-03-19 16:46:30.166 GCDDemo[15481:1177084] <NSThread: 0x7fe7fbe07cc0>{number = 1, name = main} 0
2016-03-19 16:46:30.185 GCDDemo[15481:1177084] <NSThread: 0x7fe7fbe07cc0>{number = 1, name = main} 1
2016-03-19 16:46:30.185 GCDDemo[15481:1177084] <NSThread: 0x7fe7fbe07cc0>{number = 1, name = main} 2
2016-03-19 16:46:30.185 GCDDemo[15481:1177084] <NSThread: 0x7fe7fbe07cc0>{number = 1, name = main} 3
2016-03-19 16:46:30.186 GCDDemo[15481:1177084] <NSThread: 0x7fe7fbe07cc0>{number = 1, name = main} 4
2016-03-19 16:46:30.186 GCDDemo[15481:1177084] <NSThread: 0x7fe7fbe07cc0>{number = 1, name = main} 5
2016-03-19 16:46:30.186 GCDDemo[15481:1177084] <NSThread: 0x7fe7fbe07cc0>{number = 1, name = main} 6
2016-03-19 16:46:30.186 GCDDemo[15481:1177084] <NSThread: 0x7fe7fbe07cc0>{number = 1, name = main} 7
2016-03-19 16:46:30.186 GCDDemo[15481:1177084] <NSThread: 0x7fe7fbe07cc0>{number = 1, name = main} 8
2016-03-19 16:46:30.186 GCDDemo[15481:1177084] <NSThread: 0x7fe7fbe07cc0>{number = 1, name = main} 9
// 如果把dispatch_async改为dispatch_sync那么程序就会相互等待不会执行
*/
}
// 同步任务的作用
- (void)gcdTest6
{
// 并发队列
dispatch_queue_t queue = dispatch_queue_create("cz", DISPATCH_QUEUE_CONCURRENT);
/**
例子：有一个小说网站
- 必须登录，才能下载小说
有三个任务：
1. 用户登录
2. 下载小说A
3. 下载小说B
*/
// 添加任务
// 同步任务，需要马上执行。 不开新线程
dispatch_sync(queue, ^{
NSLog(@"用户登录 %@", [NSThread currentThread]);
});
//
dispatch_async(queue, ^{
NSLog(@"下载小说A %@", [NSThread currentThread]);
});
dispatch_async(queue, ^{
NSLog(@"下载小说B %@", [NSThread currentThread]);
});
/*
2016-03-20 15:24:36.204 GCDDemo[79345:2527098] 用户登录 <NSThread: 0x7f9ee86033a0>{number = 1, name = main}
2016-03-20 15:24:36.206 GCDDemo[79345:2527592] 下载小说A <NSThread: 0x7f9ee87285d0>{number = 2, name = (null)}
2016-03-20 15:24:36.206 GCDDemo[79345:2527674] 下载小说B <NSThread: 0x7f9ee8748070>{number = 3, name = (null)}
*/
}
// 全局队列
- (void)gcdTest7
{
// 获得全局队列
/**
参数：第一个参数，一般 写 0（可以适配 iOS 7 & 8）
iOS 7
DISPATCH_QUEUE_PRIORITY_HIGH 2 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 INT16_MIN 后台优先级
iOS 8
QOS_CLASS_DEFAULT 0
第二个参数：保留参数 0
*/
dispatch_queue_t queue = dispatch_get_global_queue(0, 0);
// 添加异步任务
for (int i = 0; i < 10; i++) {
dispatch_async(queue, ^{
NSLog(@"%@ %d", [NSThread currentThread], i);
});
}
/*
2016-03-20 15:34:37.200 GCDDemo[79924:2559827] <NSThread: 0x7fea71516490>{number = 5, name = (null)} 3
2016-03-20 15:34:37.200 GCDDemo[79924:2559828] <NSThread: 0x7fea717139b0>{number = 4, name = (null)} 2
2016-03-20 15:34:37.200 GCDDemo[79924:2559722] <NSThread: 0x7fea7145d930>{number = 2, name = (null)} 1
2016-03-20 15:34:37.200 GCDDemo[79924:2559725] <NSThread: 0x7fea71513950>{number = 3, name = (null)} 0
2016-03-20 15:34:37.200 GCDDemo[79924:2560445] <NSThread: 0x7fea7145c920>{number = 6, name = (null)} 4
2016-03-20 15:34:37.201 GCDDemo[79924:2559827] <NSThread: 0x7fea71516490>{number = 5, name = (null)} 5
2016-03-20 15:34:37.201 GCDDemo[79924:2559828] <NSThread: 0x7fea717139b0>{number = 4, name = (null)} 6
2016-03-20 15:34:37.201 GCDDemo[79924:2559722] <NSThread: 0x7fea7145d930>{number = 2, name = (null)} 7
2016-03-20 15:34:37.201 GCDDemo[79924:2559725] <NSThread: 0x7fea71513950>{number = 3, name = (null)} 8
2016-03-20 15:34:37.201 GCDDemo[79924:2560445] <NSThread: 0x7fea7145c920>{number = 6, name = (null)} 9
*/
}
/**************************************************step2-end*************************************************************/
@end
2-线程间通信(重要)
/**
* 线程间通信没有用到新的API但用到了两个async嵌套的结构
*/
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
dispatch_async(dispatch_get_global_queue(0, 0), ^{
NSLog(@"%@", [NSThread currentThread]);
// 耗时操作: 放在全局队列，异步执行
// 1. url, 确定一个网络上的资源路径
NSURL *url = [NSURL URLWithString:@"http://fe.topit.me/e/d1/12/1170068721aa112d1el.jpg"];
// 2. 通过url可以下载对应的网络资源, 网络资源传输的都是二进制
NSData *data = [NSData dataWithContentsOfURL:url];
// 3. 二进制转成图片
UIImage *image = [UIImage imageWithData:data];
// 4. 更新UI，在主线程-》 直接把任务添加到主队列，就会在主队列执行
dispatch_async(dispatch_get_main_queue(), ^{
self.iconView.image = image;
NSLog(@"-----%@", [NSThread currentThread]);
});
});
}
3-管理队列任务
测试
1.dispatch_after
2.dispatch_once
#pragma mark - 延时操作
- (void)delay
{
/**
参数:
now 0
NSEC_PER_SEC: 很大的数字
*/
dispatch_time_t when = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0 * NSEC_PER_SEC));
// 参数： when : 表示从现在开始，经过多少纳秒以后
// queue ： 在哪一个队列里面执行后面的任务
// dispatch_after(when, dispatch_get_main_queue(), ^{
// NSLog(@"点我了-- %@", [NSThread currentThread]);
// });
//
dispatch_after(when, dispatch_get_global_queue(0, 0), ^{
NSLog(@"点我了-- %@", [NSThread currentThread]);
});
}
#pragma mark - 一次性执行
- (void)once
{
static dispatch_once_t onceToken;
NSLog(@"%ld", onceToken);
dispatch_once(&onceToken, ^{// 这里的代码只在第一次点击时执行
NSLog(@"%ld", onceToken);
NSLog(@"真的执行一次么？");
});
NSLog(@"完成");
/*
2016-03-21 14:39:45.532 08-GCD的其他用法[2721:1579052] 0
2016-03-21 14:39:45.533 08-GCD的其他用法[2721:1579052] 140734671969216
2016-03-21 14:39:45.533 08-GCD的其他用法[2721:1579052] 真的执行一次么？
2016-03-21 14:39:45.533 08-GCD的其他用法[2721:1579052] 完成
2016-03-21 14:40:08.774 08-GCD的其他用法[2721:1579052] -1
2016-03-21 14:40:08.774 08-GCD的其他用法[2721:1579052] 完成
2016-03-21 14:40:18.730 08-GCD的其他用法[2721:1579052] -1
2016-03-21 14:40:18.730 08-GCD的其他用法[2721:1579052] 完成
*/
}4-使用队列组
测试
1.dispatch_group_create
2.dispatch_group_async
3.dispatch_group_notify
4.
#pragma mark - 调度组(分组)
- (void)group
{
/**
应用场景：
开发的时候，有的时候出现多个网络请求都完成以后（每一个网络请求的事件长短不一定），再统一通知用户
比如： 下载小说：三国演义， 红楼梦， 金X梅
*/
// 实例化一个调度组
dispatch_group_t group = dispatch_group_create();
// 队列
dispatch_queue_t queue = dispatch_get_global_queue(0, 0);
// 任务添加到队列queue
dispatch_group_async(group, queue, ^{
NSLog(@"下载小说A---%@", [NSThread currentThread]);
});
dispatch_group_async(group, queue, ^{
NSLog(@"下载小说B---%@", [NSThread currentThread]);
});
dispatch_group_async(group, queue, ^{
NSLog(@"下载小说X---%@", [NSThread currentThread]);
});
// 获得所有调度组里面的异步任务完成的通知
// dispatch_group_notify(group, queue, ^{
// NSLog(@"下载完成，请观看%@", [NSThread currentThread]); // 异步的
// });
//注意点： 在调度组完成通知里，可以跨队列通信
dispatch_group_notify(group, dispatch_get_main_queue(), ^{
// 更新UI，在主线程
NSLog(@"下载完成，请观看%@", [NSThread currentThread]); // 异步的
});
/*
2016-03-21 12:41:32.640 08-GCD的其他用法[2466:1186856] 下载小说B---<NSThread: 0x7fbab241a5d0>{number = 3, name = (null)}
2016-03-21 12:41:32.640 08-GCD的其他用法[2466:1186855] 下载小说A---<NSThread: 0x7fbab250b090>{number = 2, name = (null)}
2016-03-21 12:41:32.640 08-GCD的其他用法[2466:1186859] 下载小说X---<NSThread: 0x7fbab240d120>{number = 4, name = (null)}
2016-03-21 12:41:32.641 08-GCD的其他用法[2466:1186625] 下载完成，请观看<NSThread: 0x7fbab2606d90>{number = 1, name = main}
*/
}
时间： 2024-11-06 01:11:46