Add a SelectableGenericAdapter as subclass of GenericAdapter

`SelectableGenericAdapter` extends `GenericAdapter` with support for marking one item as selected.
This commit is contained in:
lynxnb 2022-07-31 01:56:22 +02:00 committed by Mark Collins
parent e93fdce845
commit a59f2baa3a
2 changed files with 51 additions and 1 deletions

View File

@ -21,7 +21,7 @@ typealias OnFilterPublishedListener = () -> Unit
/**
* Can handle any view types with [GenericListItem] implemented, [GenericListItem] are differentiated by the return value of [GenericListItem.getViewBindingFactory]
*/
class GenericAdapter : RecyclerView.Adapter<GenericViewHolder<ViewBinding>>(), Filterable {
open class GenericAdapter : RecyclerView.Adapter<GenericViewHolder<ViewBinding>>(), Filterable {
companion object {
private val DIFFER = object : DiffUtil.ItemCallback<GenericListItem<ViewBinding>>() {
override fun areItemsTheSame(oldItem : GenericListItem<ViewBinding>, newItem : GenericListItem<ViewBinding>) = oldItem.areItemsTheSame(newItem)
@ -139,3 +139,49 @@ class GenericAdapter : RecyclerView.Adapter<GenericViewHolder<ViewBinding>>(), F
}
}
}
/**
* A [GenericAdapter] that supports marking one item as selected. List items that need to access the selected position should inherit from [SelectableGenericListItem]
*/
class SelectableGenericAdapter(private val defaultPosition : Int) : GenericAdapter() {
var selectedPosition : Int = defaultPosition
/**
* Sets the selected position to [position] and notifies previous and new selected positions
*/
fun selectAndNotify(position : Int) {
val previousSelectedPosition = selectedPosition
selectedPosition = position
notifyItemChanged(previousSelectedPosition)
notifyItemChanged(position)
}
/**
* Sets the selected position to [position] and only notifies the previous selected position
*/
fun selectAndNotifyPrevious(position : Int) {
val previousSelectedPosition = selectedPosition
selectedPosition = position
notifyItemChanged(previousSelectedPosition)
}
/**
* Removes the item at [position] from the list and updates the selected position accordingly
*/
override fun removeItemAt(position: Int) {
super.removeItemAt(position)
if (position < selectedPosition)
selectedPosition--
else if (position == selectedPosition)
selectAndNotify(defaultPosition)
}
/**
* Inserts the given item to the list at [position] and updates the selected position accordingly
*/
override fun addItemAt(position : Int, item : GenericListItem<out ViewBinding>) {
super.addItemAt(position, item)
if (position <= selectedPosition)
selectedPosition++
}
}

View File

@ -37,3 +37,7 @@ abstract class GenericListItem<V : ViewBinding> {
open val fullSpan : Boolean = false
}
abstract class SelectableGenericListItem<V : ViewBinding> : GenericListItem<V>() {
val selectableAdapter get() = super.adapter as SelectableGenericAdapter?
}