recyclerView中的diffutil回呼無法正常作業

我正在嘗試在 RecyclerView 串列上添加一些搜索而不使用

notifyDataSetChanged()

而不是使用它

diffutil.callback()

但問題是它正確更改了串列，但沒有正確更改 UI

這是我的代碼，我會解釋它

class RecordsAdapter : RecyclerView.Adapter<RecordsAdapter.ViewHolder>() {

    var adapterList = listOf<CustomerModel>()

    var modelList = listOf<CustomerModel>()
        set(value) {
            adapterList = value
            field = value
        }

    private var modelListFiltered = listOf<CustomerModel>()

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder =
        ViewHolder(CustomerCellBinding.inflate(LayoutInflater.from(parent.context), parent, false))

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        holder.bind(adapterList[position])
    }

    override fun getItemCount(): Int = adapterList.size

    fun filter(isFiltered: Boolean, filterSearch: String) {
        if (isFiltered) {
            val filter = modelList
                .filter {
                    it.name.contains(filterSearch) || it.id.contains(filterSearch)
                }

            modelListFiltered = filter
        }

        adapterList = if (isFiltered) modelListFiltered else modelList

        val diff = CartDiffUtil(
            if (isFiltered) modelList else modelListFiltered,
            if (isFiltered) modelListFiltered else modelList
        )

        DiffUtil.calculateDiff(diff).dispatchUpdatesTo(this)
    }

    inner class ViewHolder(private var binding: CustomerCellBinding) :
        RecyclerView.ViewHolder(binding.root) {

        fun bind(model: CustomerModel) {
            binding.let {
                it.model = model
                it.executePendingBindings()
            }
        }
    }
}

class CartDiffUtil(private val oldList: List<CustomerModel>, private val newList: List<CustomerModel>) : DiffUtil.Callback() {

    override fun getOldListSize() = oldList.size

    override fun getNewListSize() = newList.size

    override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean =
    oldList[oldItemPosition].id == newList[newItemPosition].id

    override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean =
    oldList[oldItemPosition] == newList[newItemPosition]
}

所以我呼叫過濾器函式進行過濾，如果有任何過濾器，我會發送兩個引數，第二個是搜索。

現在問題出現在這種情況下

0.搜索“”

1.搜索“測驗2”

2.搜索“測驗4”

3.搜索“測驗2”

4.搜索“”

正如您在圖片中看到的，當我在“測驗 4”之后搜索“測驗 2”時，它一直顯示“測驗 4”，即使我清除搜索，它也會給我兩個“測驗 4”單元格而不是一個“測驗” 2”和一個“測驗4”

希望我的問題很清楚。

謝謝。

uj5u.com熱心網友回復：

我猜您對三個串列屬性的處理會導致某些情況下，在 DiffUtil 的前后可能存在相同的串列實體，因此無法成功比較它們。

此外，當您想使用 DiffUtil 時，使用 ListAdapter 而不是 RecyclerView.Adapter 要容易得多。請注意，當您使用 ListAdapter 時，您使用 ItemCallback 而不是 Callback。ItemCallback 更簡單。

嘗試這樣做，只有modelList當它或過濾器更改時，您確定新串列是什么并將其提交給 ListAdapter 并讓它處理更改。

class RecordsAdapter : ListAdapter<CustomerModel, RecordsAdapter.ViewHolder>(CustomerModelCallback) {

    var modelList = listOf<CustomerModel>()
        set(value) {
            field = value
            resync()
        }

    private var filterText: String = ""
    private var isFiltered: Boolean = false

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder =
        ViewHolder(CustomerCellBinding.inflate(LayoutInflater.from(parent.context), parent, false))

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        holder.bind(adapterList[position])
    }

    fun filter(isFiltered: Boolean, filterText: String = "") {
        this.isFiltered = isFiltered
        this.filterText = filterText
        resync()
    }

    private fun resync() {
        val newList = when {
            isFiltered && filterText.isNotEmpty() -> 
                modelList.filter {
                    it.name.contains(filterSearch) || it.id.contains(filterSearch)
                }
            else -> modelList
        }

        submitList(newList)
    }

    // view holder...
}

object CustomerModelCallback : DiffUtil.ItemCallback<CustomerModel>() {
    override fun areItemsTheSame(oldItem: CustomerModel, newItem: CustomerModel): Boolean =
        oldItem.id == newItem.id

    override fun areContentsTheSame(oldItem: CustomerModel, newItem: CustomerModel): Boolean =
        oldItem == newItem
}

標籤：安卓 安卓工作室 科特林 android-recyclerview android-diffutils

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