我在RecyclerView中实现了拖放,并且正在使用DiffUtil
调度更新。但是看来DiffUtil
并没有以某种方式将项目移动分派到适配器。但是,如果我在适配器上调用notifyItemMoved()
,它将起作用。
在适配器中
fun updateItems(items: List<Item?>) {
val diffResult = DiffUtil.calculateDiff(MyDiffCallback(this.items, items), true)
diffResult.dispatchUpdatesTo(this)
this.items = items
}
存储库
fun swap(fromPosition: Int, toPosition: Int) {
val list = liveItems.value
Collections.swap(list, fromPosition, toPosition)
liveItems.value = list
}
项目
data class Item(val id: String, @StringRes val title: Int, @DrawableRes val icon: Int) {
override fun equals(other: Any?): Boolean {
if (this === other) return true
if (javaClass != other?.javaClass) return false
other as Item
if (id != other.id) return false
if (title != other.title) return false
if (icon != other.icon) return false
return true
}
override fun hashCode(): Int {
var result = id.hashCode()
result = 31 * result + title
result = 31 * result + icon
return result
}
}
MyDiffCallback
class MyDiffCallback(private val oldList: List<Item?>?, private val newList: List<Item?>) :
DiffUtil.Callback() {
override fun getOldListSize(): Int {
return oldList?.size ?: 0
}
override fun getNewListSize(): Int {
return newList.size
}
override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
return oldList!![oldItemPosition]!!.id == newList[newItemPosition]!!.id
}
override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
return oldList!![oldItemPosition]!! == newList[newItemPosition]
}
}
请注意id
变量is specific to each
项目`。