Should Item.unbind() on all items be called when the Activity/Fragment holding reference to the adapter is destroyed?

I’m experiencing some unexpected issues with Items and cleaning up references when items should be unbound. But, maybe I’m not understanding how the unbind function is supposed to work.

If I set up listeners or RxJava subscriptions in bind(viewHolder, position) of a custom Item class and I exit the activity which holds reference to the adapter containing these items, shouldn’t unbind(holder) be called on all items? Is there something specific I have to call before the activity/fragment is stopped?

In my particular case, unbind(holder) is never called for any of the items in my adapter.

I’m happy to create a bug ticket if this turns out to be a bug.

[TylerMcCraw]

Ok 👍 I’ll give the LifecycleObserver option a shot and report back just so other folks can see a resolution. But, feel free to close the ticket.

Really appreciate your help!

[ValCanBuild]

unbind(holder) is called whenever a ViewHolder is recycled (called from RecyclerView.Adapter.onViewRecycled method).

Activities/Fragments do not explicitly alert RecyclerView adapters about lifecycle changes.

There is two things you can do here depending on your use case. One of them is to override the onViewAttachedToWindow and onViewDetachedFromWindow functions in Item. These are driven from the corresponding functions from the recyclerview adapter. But you will NOT get an onViewDetachedFromWindow event when the activity/fragment is stopped or destroyed.

What it sounds like to me is that your Items need to implement LifecycleObserver. And if your RecyclerView is used within an Activity it should be really simple to use:

class MyItem() : Item(), LifecycleObserver {

    override fun bind(viewHolder: GroupieViewHolder, position: Int) {
        (viewHolder.itemView.context as AppCompatActivity).lifecycle.addObserver(this)
    }

    override fun unbind(viewHolder: GroupieViewHolder) {
        super.unbind(viewHolder)
        (viewHolder.itemView.context as AppCompatActivity).lifecycle.removeObserver(this)
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_STOP)
    fun onStop() {
        //perform onStopLogic
    }
}

Things are a little bit tricker if you want to bind it to a Fragment lifecycle. Since the context of the viewHolder.itemView will ultimately be an Activity one. In that case you’d need to pass the reference of the Fragment as a LifecycleOwner to your items.

Does this help?