Swift 反应可可如何避免在collectionView'；s细胞

当我重新加载数据时，这种方式将再次实现，并且信号将被多次订阅，如何解决它并确保只订阅一次？

最后，我自己解决它。。。 我用“takeUntil”的方式，像这样

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier(identifier, forIndexPath: indexPath) as! ComposeCell
    cell.deletePictureSignal.subscribeNext { (response) -> Void in
        print("delete picture")
        let deleteIndex = (self.pictureView.indexPathForCell(cell)?.item)!
        self.pictures.removeAtIndex(deleteIndex)
        //            self.pictureView.reloadData()
    }
    cell.addPictureSignal.subscribeNext { (response) -> Void in
        print("add picture")
        self.selectedIndex = (self.pictureView.indexPathForCell(cell)?.item)!
        let imagePicker = UIImagePickerController()
        imagePicker.delegate = self
        self.presentViewController(imagePicker, animated: true, completion: nil)
    }
   return cell
}

---

最后，我自己解决了。。。 我用“takeUntil”的方式，像这样

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier(identifier, forIndexPath: indexPath) as! ComposeCell
    cell.deletePictureSignal.subscribeNext { (response) -> Void in
        print("delete picture")
        let deleteIndex = (self.pictureView.indexPathForCell(cell)?.item)!
        self.pictures.removeAtIndex(deleteIndex)
        //            self.pictureView.reloadData()
    }
    cell.addPictureSignal.subscribeNext { (response) -> Void in
        print("add picture")
        self.selectedIndex = (self.pictureView.indexPathForCell(cell)?.item)!
        let imagePicker = UIImagePickerController()
        imagePicker.delegate = self
        self.presentViewController(imagePicker, animated: true, completion: nil)
    }
   return cell
}