关于子线程中代码是否执行完毕

如下面代码所示，在text1 方法中又开辟了新的线程来执行for循环，但我想在for循环执行完毕后在执行text2，请问应该怎么操作

• (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{ NSLog(@"%s",__func__); NSBlockOperation *ope1 = [NSBlockOperation blockOperationWithBlock:^{ [self text1]; }]; NSBlockOperation *ope2 = [NSBlockOperation blockOperationWithBlock:^{ [self text2]; }]; [ope2 addDependency:ope1]; [self.queue addOperation:ope1]; [self.queue addOperation:ope2];

}

• (void)text1{
  dispatch_queue_t queue = dispatch_queue_create("111", NULL);
  dispatch_async(queue, ^{
  [self forCircle];
  });
  }

• (void)forCircle{
  int a = 10000000;
  for (int i = 0; i < a; ++i) {
  //sleep(0.5);
  if (i == a - 1) {
  self.done = YES;
  }
  }
  }

• (void)text2{
  if (self.queue.operations.count == 1) {
  if (self.done == YES) {
  NSLog(@"2222");
  }
  }

}

你用sem信号量来进行同步等