IndexOutOfBoundsException ListAdapter

Question

我正在从通常的RecyclerView迁移到ListAdapter:

abstract class BaseAdapter<T>(
@LayoutRes
val normalLayoutId: Int,
@LayoutRes
val loadingLayoutId: Int = R.layout.progress_loading,
sm: (T, T) -> Boolean,
val itemsCells: ArrayList<T?> = ArrayList()
) : ListAdapter<T, RecyclerView.ViewHolder>(TaskDiffCallbac(sm)) {
val VIEW_TYPE_ITEM = 0
val VIEW_TYPE_LOADING = 1
class ItemViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView)
class LoadingViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView)
fun addData(dataViews: ArrayList<T>) {
itemsCells.addAll(dataViews)
this.submitList(dataViews)
notifyDataSetChanged()
}

override fun getItemViewType(position: Int): Int {
return if (getItem(position) == null) {
VIEW_TYPE_LOADING
} else {
VIEW_TYPE_ITEM
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
return if (viewType == Constant.VIEW_TYPE_ITEM) {
val view =
LayoutInflater.from(parent.context).inflate(normalLayoutId, parent, false)
ItemViewHolder(view)
} else {
val view =
LayoutInflater.from(parent.context).inflate(loadingLayoutId, parent, false)
LoadingViewHolder(view)
}
}
fun addLoadingView() {
itemsCells.add(null)
submitList(itemsCells)
}
fun removeLoadingView() {
if (itemsCells.size != 0) {
itemsCells.removeAt(itemsCells.size - 1)
submitList(itemsCells)
}
}
fun clearItems() {
itemsCells.clear()
submitList(itemsCells)
}
class TaskDiffCallbac<T>(val sm: (T, T) -> Boolean) : DiffUtil.ItemCallback<T>() {
override fun areItemsTheSame(oldItem: T, newItem: T): Boolean {
return sm(oldItem, newItem)
}
@SuppressLint("DiffUtilEquals")
override fun areContentsTheSame(oldItem: T, newItem: T): Boolean {
return oldItem == newItem
}
}
}

但是在调试时我得到了这个异常:

java.lang.IndexOutOfBoundsException: Index: 20, Size: 20
2021-02-19 11:38:11.770 5602-5668/? E/AndroidRuntime: FATAL EXCEPTION: pool-1-thread-1
Process: com.timelysoft.shelter, PID: 5602
java.lang.IndexOutOfBoundsException: Index: 20, Size: 20
at java.util.ArrayList.get(ArrayList.java:437)
at androidx.recyclerview.widget.AsyncListDiffer$1$1.areItemsTheSame(AsyncListDiffer.java:306)
at androidx.recyclerview.widget.DiffUtil.diffPartial(DiffUtil.java:268)
at androidx.recyclerview.widget.DiffUtil.calculateDiff(DiffUtil.java:145)
at androidx.recyclerview.widget.DiffUtil.calculateDiff(DiffUtil.java:105)
at androidx.recyclerview.widget.AsyncListDiffer$1.run(AsyncListDiffer.java:292)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)

有什么问题吗?

Answer 1

abstract class BaseAdapter<T>(
@LayoutRes
val normalLayoutId: Int,
@LayoutRes
val loadingLayoutId: Int = R.layout.progress_loading,
sm: (T, T) -> Boolean,
val itemsCells: ArrayList<T?> = ArrayList()
) : ListAdapter<T, RecyclerView.ViewHolder>(CustomDiffCallbac(sm)) {
val VIEW_TYPE_ITEM = 0
val VIEW_TYPE_LOADING = 1
class ItemViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView)
class LoadingViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView)
fun addData(dataViews: ArrayList<T>) {
itemsCells.addAll(dataViews)
this.submitList(itemsCells)
}

override fun getItemViewType(position: Int): Int {
return if (itemsCells[position] == null) {
VIEW_TYPE_LOADING
} else {
VIEW_TYPE_ITEM
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
return if (viewType == Constant.VIEW_TYPE_ITEM) {
val view =
LayoutInflater.from(parent.context).inflate(normalLayoutId, parent, false)
ItemViewHolder(view)
} else {
val view =
LayoutInflater.from(parent.context).inflate(loadingLayoutId, parent, false)
LoadingViewHolder(view)
}
}
fun addLoadingView() {
itemsCells.add(null)
submitList(itemsCells)
notifyItemInserted(itemsCells.size-1)
}
fun removeLoadingView() {
if (itemsCells.size != 0) {
val index = itemsCells.size - 1
itemsCells.removeAt(index)
submitList(itemsCells)
notifyItemRemoved(index)
}
}
fun clearItems() {
itemsCells.clear()
submitList(itemsCells)
}
class CustomDiffCallbac<T>(val sm: (T, T) -> Boolean) : DiffUtil.ItemCallback<T>() {
override fun areItemsTheSame(oldItem: T, newItem: T): Boolean {
return sm(oldItem, newItem)
}

@SuppressLint("DiffUtilEquals")
override fun areContentsTheSame(oldItem: T, newItem: T): Boolean {
return oldItem == newItem
}
}
}