最近，我遇到了一個對我來說有點難以解決的問題
我需要在 List 配接器中放置 2 個模型，但它總是說 2 個型別的引數預期
這是我的整個配接器類：
class TransactionHistory() :
ListAdapter<Transaction, RecyclerView.ViewHolder>(BillDiffCallback()) {
private val ITEM_VIEW_TYPE_EMPTY = 0
private val ITEM_VIEW_TYPE_ITEM = 1
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
return when (viewType) {
ITEM_VIEW_TYPE_ITEM -> ViewHolder.from(parent)
ITEM_VIEW_TYPE_EMPTY -> EmptyViewHolder.from(parent)
else -> throw ClassCastException("Unknown viewType $viewType")
}
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
when (holder) {
is ViewHolder -> {
val item = getItem(position)
holder.bind(item, clickListener)
// holder.bind2(Bank, clickListener)
}
is EmptyViewHolder -> {
holder.bind()
}
}
}
lateinit var clickListener: AdapterListener2
fun setOnclickListener(listener: AdapterListener2) {
clickListener = listener
}
override fun getItemViewType(position: Int): Int {
return if (itemCount > 0)
ITEM_VIEW_TYPE_ITEM
else
ITEM_VIEW_TYPE_EMPTY
}
class ViewHolder
private constructor(val binding: ItemUserTransactionListBinding) :
RecyclerView.ViewHolder(binding.root) {
fun bind(item: Transaction, adapterListener2: AdapterListener2) {
binding.transaction = item
binding.clickListener = adapterListener2
binding.executePendingBindings()
if (item.type == "payPayment") {
binding.transactionStatus.text = "?????? ???"
} else if (item.type == "decrease") {
binding.transactionStatus.text = "??????"
} else if (item.type == "increase") {
binding.transactionStatus.text = "?????"
}
if (item.decrease == null) {
binding.amount.text = item.increase
} else {
binding.amount.text = item.decrease
}
}
fun bind2(item2: Bank, adapterListener2: AdapterListener2) {
binding.bankInfo = item2
binding.clickListener = adapterListener2
binding.executePendingBindings()
}
companion object {
fun from(parent: ViewGroup): ViewHolder {
val layoutInflater = LayoutInflater.from(parent.context)
val binding = ItemUserTransactionListBinding.inflate(layoutInflater, parent, false)
return ViewHolder(binding)
}
}
}
}
class EmptyViewHolder private constructor(val binding: ItemUserTransactionListBinding) :
RecyclerView.ViewHolder(binding.root) {
fun bind() {
binding.executePendingBindings()
}
companion object {
fun from(parent: ViewGroup): EmptyViewHolder {
val layoutInflater = LayoutInflater.from(parent.context)
val binding = ItemUserTransactionListBinding.inflate(layoutInflater, parent, false)
return EmptyViewHolder(binding)
}
}
}
class BillDiffCallback : DiffUtil.ItemCallback<Transaction>() {
override fun areItemsTheSame(oldItem: Transaction, newItem: Transaction): Boolean {
return oldItem.transId == newItem.transId
}
override fun areContentsTheSame(
oldItem: Transaction,
newItem: Transaction
): Boolean {
return oldItem == newItem
}
}
class AdapterListener2(
val clickListener: (id: Long?) -> Unit,
val deleteListener: (category: Transaction) -> Unit
) {
fun onclick(transaction: Transaction) = clickListener(transaction.userId)
fun onDeleteClick(userInfo: Transaction) = deleteListener(userInfo)
}
每當我在這里放置第二個模型時：
ListAdapter<Transaction, **Bank**, RecyclerView.ViewHolder>(BillDiffCallback()) {}
它說 2 型別的引數預期。
我不知道它是否對你有幫助，但有人告訴我我必須在 Kotlin 中使用 join
感謝您的回答:)
uj5u.com熱心網友回復：
您可以僅基于單個資料源構建串列。如果您想擁有多個資料源，您應該創建第三個資料模型并在其中添加其他兩個模型。
data class ListData(val transaction : Transaction , val Bank : Bank)
ListView/Recycler 視圖將根據傳遞的物件串列創建多個串列項。
ListAdapter<ListData, RecyclerView.ViewHolder>
uj5u.com熱心網友回復：
ListAdaper 只能接受一個資料模型，但是您可以使用另一個類添加多個專案，例如 Sealed Class
sealed class DataItem {
abstract val id: Long
data class TransactionItem(val transaction: Transaction): DataItem() {
override val id = transaction.transId
}
object Empty: DataItem() {
override val id = Long.MIN_VALUE
}
}
并在您的 ListAdapter 中為您的代碼處理這個唯一的類，您將需要應用此更改
class TransactionHistory() :
ListAdapter<DataItem, RecyclerView.ViewHolder>(BillDiffCallback()) {
private val ITEM_VIEW_TYPE_EMPTY = 0
private val ITEM_VIEW_TYPE_ITEM = 1
private val adapterScope = CoroutineScope(Dispatchers.Default)
fun addTransactions(list: List<Transaction>?) {
adapterScope.launch {
val items: List<DataItem> = when {
list == null || list.isEmpty() -> listOf(DataItem.Empty)
else -> list.map { DataItem.TransactionItem(it) }
}
withContext(Dispatchers.Main) {
submitList(items)
}
}
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
when (holder) {
is ViewHolder -> {
val item = getItem(position) as DataItem.TransactionItem
holder.bind(item, clickListener)
}
is EmptyViewHolder -> holder.bind()
}
}
override fun getItemViewType(position: Int): Int {
return when (getItem(position)) {
is DataItem.Empty -> ITEM_VIEW_TYPE_EMPTY
is DataItem.TransactionItem -> ITEM_VIEW_TYPE_ITEM
}
}
}
class BillDiffCallback : DiffUtil.ItemCallback<DataItem>() {
override fun areItemsTheSame(oldItem: DataItem, newItem: DataItem): Boolean {
return oldItem.id == newItem.id
}
override fun areContentsTheSame(oldItem: DataItem, newItem: DataItem): Boolean {
return oldItem == newItem
}
}
sealed class DataItem {
abstract val id: Long
data class TransactionItem(val transaction: Transaction): DataItem() {
override val id = transaction.transId
}
object Empty: DataItem() {
override val id = Long.MIN_VALUE
}
}
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標籤：安卓 数据库 科特林 加入 android-recyclerview
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