Loosing attribute state for first time scrolling.

    data class Model(
        private val media: Media,
        private val thmPath: String,
        private val clickListener: (Model, Media, Boolean) -> Any?,
        private val longClickListener: (Model, Media, Boolean) -> Any?
    ) : EpoxyModel<MediaItemView>(), MediaEpoxyModel {

        @EpoxyAttribute private var isSelected: Boolean = false
        private var mediaItemView: MediaItemView? = null

        override fun getDefaultLayout() = R.layout.media_item_view

        override fun shouldSaveViewState(): Boolean = true

        override fun bind(view: MediaItemView) {
            Timber.d("BIND model: ${this.id()} hash: ${hashCode()} isSelected: $isSelected")
            mediaItemView = view
            view.bind(media, thmPath)

Somehow isSelected is getting reset for firsttime scrolling. Steps:

Select first grid item through long press which set isSelected true. Scroll down ~30 items with header Scroll up so bind perform for that selected item, but somehow getting isSelected=false

This problem happens only first-time selection, else getting a perfect attribute value as true if selected.

[elihart]

This isn’t the correct way to use models. They should be immutable, you can’t change them once they are added to the EpoxyController. Read more in the wiki https://github.com/airbnb/epoxy/wiki/Epoxy-Controller

the correct way to handle this is to have a callback to your controller to update some state there that keeps a list of all selected items. when you build models you should set the model prop based on that list. When the list is updated models should be rebuilt.

[gevariya-ajit]

Thank you @elihart, requestBuildModels working as expected