构造函数数组返回空列表

如何解决构造函数数组返回空列表

大家好，我正在为我的项目实施搜索视图过滤器。为此，我创建了那个过滤器类。我从构造函数获取 mainList 。该数组来自适配器类。但是当我从 FilterFood 类调用这个列表时，它返回空列表。适配器正在通过网络获取该阵列。

适配器类：

public class Transaction extends BaseEntityUuid {
   @ManyToOne(fetch = FetchType.LAZY)
   @JoinColumn(name = "CNTRB_TYP_ID",referencedColumnName = "CNTRB_TYP_ID")
   private Contribution contributionTyp;

   @Column(name = "CNTRB_TYP_ID")
   private String cntrbTypId;
   ...
}

public class ContributionTyp extends BaseEntityUuid {

@OneToMany(targetEntity = Transaction.class,mappedBy = "contributionTyp",fetch = FetchType.LAZY)
private Set<Transaction> transactions;

@NotNull
@Column(name = "CNTRB_TYP_ID")
private String cntrbTypId;
...
}

过滤器类：

class CreateListAdapter(var newFoodList : ArrayList<GroceryModel>) : RecyclerView.Adapter<Holder>() {
private var selectedList : ArrayList<String> = arrayListOf()
private val filter = FilterFood(this,newFoodList)
//var tempList = ArrayList<GroceryModel>()

override fun onCreateViewHolder(parent: ViewGroup,viewType: Int): Holder {
    val itemView = LayoutInflater.from(parent.context)
        .inflate(R.layout.createlist_item,parent,false)
        //tempList = newFoodList

    return Holder(itemView)
}

override fun onBindViewHolder(holder: Holder,position: Int) {

    holder.createFoodText.text = newFoodList[position].besinİsim

    holder.createFoodText.setOnClickListener {
        if (holder.createFoodText.isChecked){
            newFoodList[position].besinİsim?.let { it1 -> selectedList.add(it1) }
            Log.i("sdasda",selectedList.toString())
        }
        else{
            newFoodList[position].besinİsim?.let { it1 -> selectedList.remove(it1)}
            Log.i("sdasda",selectedList.toString())
        }
    }
}

override fun getItemCount() = newFoodList.size

class Holder(itemView: View) : RecyclerView.ViewHolder(itemView){
    val createFoodText : CheckBox = itemView.findViewById(R.id.checkBoxItem)
}

 fun getFilteredList(s : String) {
    filter.filter(s)
}

}

片段：

class FilterFood(private val adapter : CreateListAdapter,private val mainList : ArrayList<GroceryModel>) : Filter() {

private var filteredList : ArrayList<GroceryModel> = arrayListOf()

override fun performFiltering(constraint: CharSequence?): FilterResults {
    Log.i("ssss",mainList.toString())
    if (constraint == null || constraint.length == 0){
        filteredList = mainList
    }
    else{
        val filterPattern : String = constraint.toString().toLowerCase().trim()

        for (item in mainList){
            if (item.besinİsim.toString().toLowerCase().contains(filterPattern)){
                filteredList.add(item)
            }
        }
    }
    val results = FilterResults()
    results.values = filteredList

    return results
}

override fun publishResults(constraint: CharSequence?,results: FilterResults) {
    adapter.newFoodList = results?.values as ArrayList<GroceryModel>
    adapter.notifyDataSetChanged()
}

}

解决方法

您的 Filter 使用了对旧 newFoodList 的引用。如果我理解正确，您必须使用 adapter.newFoodList 而不是 mainList