ios - Nested dispatch_async (dispatch_async inside another dispatch_async) -

how call dispatch_async calls inside dispatch_async

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");  }); 

and here 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");     }); } 

and output :
main
end
block1
block2
final
block1 end
block2 end
block3

but need
main
end
block1
block2
block1 end
block2 end
block3
final

you need notified group of yours mymethod. yours code be:

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; }