Java 使用DiffUtil删除旧的recyclerview适配器更新列表?
我正在为我的RecyclerView使用DiffUtil,它可以很好地用于一个加载列表,但是当尝试将新列表更新为当前列表时,它会删除旧数据 这是我的适配器Java 使用DiffUtil删除旧的recyclerview适配器更新列表?,java,android,list,kotlin,android-recyclerview,Java,Android,List,Kotlin,Android Recyclerview,我正在为我的RecyclerView使用DiffUtil,它可以很好地用于一个加载列表,但是当尝试将新列表更新为当前列表时,它会删除旧数据 这是我的适配器 class SettingRecyclerView(private val interaction: Interaction? = null) : RecyclerView.Adapter<RecyclerView.ViewHolder>() { val DIFF_CALLBACK = object : Diff
class SettingRecyclerView(private val interaction: Interaction? = null) :
RecyclerView.Adapter<RecyclerView.ViewHolder>() {
val DIFF_CALLBACK = object : DiffUtil.ItemCallback<SettingItem>() {
override fun areItemsTheSame(oldItem: SettingItem, newItem: SettingItem): Boolean {
return oldItem.id == newItem.id
}
override fun areContentsTheSame(oldItem: SettingItem, newItem: SettingItem): Boolean {
return oldItem.hashCode() == newItem.hashCode()
}
}
private val differ = AsyncListDiffer(this, DIFF_CALLBACK)
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
return SettingViewHolder(
ItemRvBinding.inflate(
LayoutInflater.from(parent.context),
parent,
false
),
interaction
)
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
when (holder) {
is SettingViewHolder -> {
holder.bind(differ.currentList.get(position))
}
}
}
override fun getItemCount(): Int {
return differ.currentList.size
}
fun submitList(list: List<SettingItem>) {
differ.submitList(list)
}
class SettingViewHolder
constructor(
private val binding: ItemRvBinding,
private val interaction: Interaction?
) : RecyclerView.ViewHolder(binding.root) {
fun bind(item: SettingItem) = with(binding.root) {
binding.root.setOnClickListener {
interaction?.onItemSelected(adapterPosition, item)
}
binding.settingTitle.text = item.title
}
}
interface Interaction {
fun onItemSelected(position: Int, item: SettingItem)
}
}
我不知道到底是什么问题导致了这个问题,是否有其他方法可以使用DiffUtil更新列表,或者我必须使用notifiydatachanged或其他什么?如果您不使用
数据类
,这将导致问题。
问题是您正在比较方法中的设置项。hashCode()
是内容相同的()
方法
override fun areContentsTheSame(oldItem: SettingItem, newItem: SettingItem): Boolean {
\\ You need to pass the same object to evaluate to true.
return oldItem.hashCode() == newItem.hashCode()
}
解决方案:
您需要以正确的方式使用数据类
,以便编译器自动从主构造函数中声明的所有属性派生hashCode()
和equals()
见此:
或者您应该手动比较SettingsItem
的属性
override fun areContentsTheSame(oldItem: SettingItem, newItem: SettingItem): Boolean {
\\ You need to pass the same object to evaluate to true.
return oldItem.hashCode() == newItem.hashCode()
}