我们常用的GCD调度组方式
1 //GCD常用调度组写法
2 -(void)demo1{
3
4 //创建调度组和队列
5 dispatch_group_t group = dispatch_group_create();
6 dispatch_queue_t queue = dispatch_queue_create("ChangYong", DISPATCH_QUEUE_CONCURRENT);
7
8 //将任务添加到调度组
9 dispatch_group_async(group, queue, ^{
10 NSLog(@"耗时操作_11111111");
11 });
12 dispatch_group_async(group, queue, ^{
13 //模拟耗时操作
14 [NSThread sleepForTimeInterval:2];
15 NSLog(@"耗时操作_22222222");
16 });
17 dispatch_group_async(group, queue, ^{
18 NSLog(@"耗时操作_33333333");
19 });
20
21 //所有任务执行完毕后执行的任务
22 dispatch_group_notify(group, dispatch_get_main_queue(), ^{
23 NSLog(@"所有任务执行完毕, 更新UI操作");
24 });
25 }
GCD调度组原理
1 //GCD调度组原理方法
2 -(void)demo2{
3
4 //创建调度组和队列
5 dispatch_group_t group = dispatch_group_create();
6 dispatch_queue_t queue = dispatch_queue_create("YuanLi", DISPATCH_QUEUE_CONCURRENT);
7
8 //任务1
9 dispatch_group_enter(group);
10 dispatch_async(queue, ^{
11 NSLog(@"任务1");
12 dispatch_group_leave(group);
13 });
14
15 //任务2
16 dispatch_group_enter(group);
17 dispatch_async(queue, ^{
18 [NSThread sleepForTimeInterval:2];
19 NSLog(@"任务2");
20 dispatch_group_leave(group);
21 });
22
23 //任务3
24 dispatch_group_enter(group);
25 dispatch_async(queue, ^{
26 NSLog(@"任务3");
27 dispatch_group_leave(group);
28 });
29
30 //任务全部执行完毕
31 dispatch_group_notify(group, dispatch_get_main_queue(), ^{
32
33 NSLog(@"任务执行完毕, 刷新UI");
34 });
35
36 //等待上面代码执行完毕后在执行下面的代码, 参数2:等待超时时间
37 //dispatch_group_wait(group, DISPATCH_TIME_FOREVER);
38
39 NSLog(@"Hello");
40 }