嵌套dispatch_async (另一个dispatch_async中的dispatch_async)
嵌套dispatch_async (另一个dispatch_async中的dispatch_async)
提问于 2016-11-10 11:18:30
如何正确调用dispatch_async在dispatch_async中的调用
dispatch_group_t downloadQueue = dispatch_group_create();
dispatch_group_async(downloadQueue,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
NSLog(@"Main");
[NSThread sleepForTimeInterval:5.0];
NSLog(@"End");
[self myMethod];
});
dispatch_group_notify(downloadQueue,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH,0), ^ {
NSLog(@"FINAL");
});下面是myMethod：
-(void)myMethod
{
dispatch_group_t group = dispatch_group_create();
dispatch_group_async(group,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
// block1
NSLog(@"Block1");
[NSThread sleepForTimeInterval:5.0];
NSLog(@"Block1 End");
});
dispatch_group_async(group,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
// block2
NSLog(@"Block2");
[NSThread sleepForTimeInterval:8.0];
NSLog(@"Block2 End");
});
dispatch_group_notify(group,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
// block3
NSLog(@"Block3");
});
}和我的输出是:
Main
结束
Block1
Block2
最终
Block1结束
Block2结束
Block3
，但我需要
Main
结束
Block1
Block2
Block1结束
Block2结束
Block3
最终
回答 2
Stack Overflow用户
发布于 2016-11-10 12:25:44
只需向您的myMethod组发出通知即可。你的代码是：
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
NSLog(@"Main");
[NSThread sleepForTimeInterval:5.0];
NSLog(@"End");
dispatch_group_notify([self myMethod],dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH,0), ^ {
NSLog(@"FINAL");
});
});
-(dispatch_group_t)myMethod{
dispatch_group_t group = dispatch_group_create();
dispatch_group_async(group,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
// block1
NSLog(@"Block1");
[NSThread sleepForTimeInterval:5.0];
NSLog(@"Block1 End");
});
dispatch_group_async(group,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
// block2
NSLog(@"Block2");
[NSThread sleepForTimeInterval:8.0];
NSLog(@"Block2 End");
});
dispatch_group_notify(group,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
// block3
NSLog(@"Block3");
});
return group;
}Stack Overflow用户
发布于 2016-11-10 12:02:15
您可以在dispatch_group_wait中使用myMethod代替dispatch_group_notify。这样，只有当两个dispatch_group_async完成执行时，您的方法才会返回。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/40526295
复制相关文章
相似问题
腾讯云开发者
Copyright © 2013 - 2026 Tencent Cloud. All Rights Reserved. 腾讯云 版权所有
深圳市腾讯计算机系统有限公司 ICP备案/许可证号：粤B2-20090059 
粤公网安备44030502008569号
腾讯云计算（北京）有限责任公司 京ICP证150476号 | 京ICP备11018762号