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// SPDX-FileCopyrightText: 2024 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
package org.yuzu.yuzu_emu.adapters
import org.yuzu.yuzu_emu.model.SelectableItem
import org.yuzu.yuzu_emu.viewholder.AbstractViewHolder
/**
* Generic list class meant to take care of single selection UI updates
* @param currentList The list to show initially
* @param defaultSelection The default selection to use if no list items are selected by
* [SelectableItem.selected] or if the currently selected item is removed from the list
*/
abstract class AbstractSingleSelectionList<
Model : SelectableItem,
Holder : AbstractViewHolder<Model>
>(
final override var currentList: List<Model>,
private val defaultSelection: DefaultSelection = DefaultSelection.Start
) : AbstractListAdapter<Model, Holder>(currentList) {
var selectedItem = getDefaultSelection()
init {
findSelectedItem()
}
/**
* Changes the selection state of the [SelectableItem] that was selected and the previously selected
* item and notifies the underlying adapter of the change for those items. Invokes [callback] last.
* Does nothing if [position] is the same as the currently selected item.
* @param position Index of the item that was selected
* @param callback Lambda that's called at the end of the list changes and has the selected list
* position passed in as a parameter
*/
fun selectItem(position: Int, callback: ((position: Int) -> Unit)? = null) {
if (position == selectedItem) {
return
}
val previouslySelectedItem = selectedItem
selectedItem = position
if (currentList.indices.contains(selectedItem)) {
currentList[selectedItem].onSelectionStateChanged(true)
}
if (currentList.indices.contains(previouslySelectedItem)) {
currentList[previouslySelectedItem].onSelectionStateChanged(false)
}
onItemChanged(previouslySelectedItem)
onItemChanged(selectedItem)
callback?.invoke(position)
}
/**
* Removes a given item from the list and notifies the underlying adapter of the change. If the
* currently selected item was the item that was removed, the item at the position provided
* by [defaultSelection] will be made the new selection. Invokes [callback] last.
* @param position Index of the item that was removed
* @param callback Lambda that's called at the end of the list changes and has the removed and
* selected list positions passed in as parameters
*/
fun removeSelectableItem(
position: Int,
callback: ((removedPosition: Int, selectedPosition: Int) -> Unit)?
) {
removeItem(position)
if (position == selectedItem) {
selectedItem = getDefaultSelection()
currentList[selectedItem].onSelectionStateChanged(true)
onItemChanged(selectedItem)
} else if (position < selectedItem) {
selectedItem--
}
callback?.invoke(position, selectedItem)
}
override fun addItem(item: Model, position: Int, callback: ((Int) -> Unit)?) {
super.addItem(item, position, callback)
if (position <= selectedItem && position != -1) {
selectedItem++
}
}
override fun replaceList(newList: List<Model>) {
super.replaceList(newList)
findSelectedItem()
}
private fun findSelectedItem() {
for (i in currentList.indices) {
if (currentList[i].selected) {
selectedItem = i
break
}
}
}
private fun getDefaultSelection(): Int =
when (defaultSelection) {
DefaultSelection.Start -> currentList.indices.first
DefaultSelection.End -> currentList.indices.last
}
enum class DefaultSelection { Start, End }
}
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