android - 在 MVVM 中绑定(bind)自动完成 TextView

Question

我希望将 MVVM 模式中的自动完成 TextView 与自定义适配器绑定(bind)，但不确定如何正确执行。我尝试使用 BindingAdapter 进行绑定(bind)，就像绑定(bind)微调器一样，但过滤器出现错误。它抛出了一个非法的参数异常。我想我没有正确设置绑定(bind)适配器。任何帮助将不胜感激。

<androidx.appcompat.widget.AppCompatAutoCompleteTextView
                    android:id="@+id/customerNameTextInputLayout"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:hint="@string/customer_name"
                    android:imeOptions="actionSearch"
                    android:inputType="textAutoComplete|textAutoCorrect"
                    android:text="@={addSaleViewModel._customerName}"
                    android:selectedItemPosition="@={addSaleViewModel.selectedAutoComplete}"
                    app:partyAutoCompleteAdapter="@{addSaleViewModel.partyList}" />

这是我的适配器代码

class PartyAutoCompleteAdapter(private var items: ArrayList<AddPartyRequest>?) :
    BaseAdapter(), PartyListItemViewModel.PartyListItemViewModelListener, Filterable {

    private var listFilter: ListFilter? = null
    private var dataListAllItems: ArrayList<AddPartyRequest> = ArrayList()

    override fun getCount(): Int = items!!.size

    override fun getDropDownView(position: Int, convertView: View?, parent: ViewGroup): View {
        return getView(position, convertView, parent)
    }

    override fun getItem(position: Int) = items?.get(position)

    override fun getItemId(position: Int) = items!!.get(position).partyId.toLong()

    override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {

        lateinit var partyHolder: PartyAutoCompleteHolder

        if (convertView == null) {
            val binding: RowPartyItemViewBinding = DataBindingUtil.inflate(
                LayoutInflater.from(parent.context),
                R.layout.row_party_item_view,
                parent,
                false
            )

            partyHolder = PartyAutoCompleteHolder(binding)
            partyHolder.view.tag = partyHolder
            binding.partyItemViewModel = PartyListItemViewModel(position, items?.get(position), this)
            binding.executePendingBindings()
        } else {
            partyHolder = convertView.tag as PartyAutoCompleteHolder
        }

        return partyHolder.view
    }

    inner class PartyAutoCompleteHolder(binding: RowPartyItemViewBinding) {
        val view = binding.root
    }

    fun addItems(parties: List<AddPartyRequest>) {
        items?.clear()
        items?.addAll(parties)
        dataListAllItems.clear()
        dataListAllItems.addAll(parties)
        notifyDataSetChanged()
    }

    override fun getFilter(): Filter? {
        if (listFilter == null) {
            listFilter = ListFilter()
        }
        return listFilter
    }

    inner class ListFilter : Filter() {

        override fun performFiltering(constraint: CharSequence?): Filter.FilterResults? {
            var constraint = constraint
            val results = Filter.FilterResults()

            if (constraint != null && constraint.isNotEmpty()) {
                constraint = constraint.toString().toUpperCase()

                val filters = ArrayList<AddPartyRequest>()

                if (dataListAllItems.size === 0) {

                    val groupsResponse = AddPartyRequest("", "", "", "", "", "", "", "", "", "", "")

                    filters.add(groupsResponse)

                } else {

                    for (i in 0 until dataListAllItems.size) {
                        if (dataListAllItems.get(i).partyName.toUpperCase().contains(constraint)) {

                            val groupsResponse = AddPartyRequest(
                                dataListAllItems.get(i).address,
                                dataListAllItems.get(i).asOfToday,
                                dataListAllItems.get(i).currentBalance,
                                dataListAllItems.get(i).email,
                                dataListAllItems.get(i).gstIn,
                                dataListAllItems.get(i).partyName,
                                dataListAllItems.get(i).partyType,
                                dataListAllItems.get(i).phoneNumber,
                                dataListAllItems.get(i).state,
                                dataListAllItems.get(i).userCompanyId,
                                dataListAllItems.get(i).partyId
                            )

                            filters.add(groupsResponse)

                        }
                    }

                }
                results.count = filters.size
                results.values = filters
            } else {
                results.count = dataListAllItems.size
                results.values = dataListAllItems
            }

            return results
        }

        override fun publishResults(constraint: CharSequence, results: Filter.FilterResults?) {
            items = results?.values as ArrayList<AddPartyRequest>
            notifyDataSetChanged()
        }

    }

    override fun onItemClick(view: View, position: Int) {

    }
}

输入任何字符后我在自定义适配器中遇到的错误

java.lang.IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull, parameter constraint
        at in.diittech.diitvyapar.ui.adapter.PartyAutoCompleteAdapter$ListFilter.publishResults(Unknown Source:24)
        at android.widget.Filter$ResultsHandler.handleMessage(Filter.java:282)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

Answer 1

这就是我的做法。可能有点晚，但也许其他人可能会使用它。

自动完成 TextView :

 class BindingAutoCompleteTextView(context: Context, attributeSet: AttributeSet) : AutoCompleteTextView(context, attributeSet) {

     var selectedItem: Any? = null

 }//Cls

 //=====================================================================================================//
 //=====================================================================================================//

 @InverseBindingAdapter(attribute = "app:selectedItem")
 fun getSelectedItem(bindingActv: BindingAutoCompleteTextView): Any? {
     return bindingActv.selectedItem
 }//getSelectedItem

 //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -//

 @BindingAdapter("selectedItemAttrChanged")
 fun selectedItemAttrChanged(actv: BindingAutoCompleteTextView, listener: InverseBindingListener) {
     actv.setOnItemClickListener { parent, _, position, _ ->
         actv.selectedItem = parent.adapter.getItem(position)
         listener.onChange()
     }
 }//selectedItemAttrChanged

 //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -//

 @BindingAdapter("app:adapter")
 fun setAdapter(actv: AutoCompleteTextView, adapter: FilterableBaseAdapter?) {

     adapter?.let {
         actv.setAdapter(adapter)
     }

 }//setAdapter

 //=====================================================================================================//
 //=====================================================================================================//

 /**
  * Class to be used as type parameter in functions
  */
 abstract class FilterableBaseAdapter : BaseAdapter(), Filterable

 //=====================================================================================================//
 //=====================================================================================================//

布局:

<?xml version="1.0" encoding="utf-8"?>

<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:bind="http://schemas.android.com/tools">


    <data>

        <variable
            name="viewModel"
            type="ie.conecto.ui.salesOrder.SalesOrderViewModel" />
    </data>


    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ie.conecto.infastructure.ui.BindingAutoCompleteTextView
            android:id="@+id/acCustomer"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginStart="8dp"
            android:layout_marginTop="8dp"
            android:layout_marginEnd="8dp"
            android:completionThreshold="2"
            android:hint="@string/select_customer"
            android:textAlignment="center"
            android:textSize="20sp"
            app:adapter="@{viewModel.adapter}"
            app:selectedItem="@={viewModel.orderItem}"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:layout_width="match_parent"
            android:layout_height="19dp"
            android:background="@color/colorPrimaryLight"
            android:text='@{viewModel.orderItem.description}'
            android:textAlignment="center"
            app:layout_constraintTop_toBottomOf="@id/acCustomer" />


        <include
            layout="@layout/progress_overlay"
            bind:show="@{viewModel.showProgress}" />

    </androidx.constraintlayout.widget.ConstraintLayout>

</layout>

View 模型:

private const val TAG = "SalesOrderViewModel"

class SalesOrderViewModel(
    private val _productRepo: IProductRepo,
    private val _customerRepo: ICustomerRepo
) : ViewModel() {


    var orderItem = MutableLiveData<OrderItem?>()


    val products by lazyDeferred {
        _productRepo.getProducts()
    }


    val customers by lazyDeferred {
        _customerRepo.getCustomers()
    }

    val showProgress: LiveData<Boolean>
        get() = _showProgress
    private var _showProgress = MutableLiveData<Boolean>()


    val adapter: LiveData<ProductAutoCompleteTextViewAdapter>
        get() = _adapter
    private var _adapter = MutableLiveData<ProductAutoCompleteTextViewAdapter>()

    var backgroundTaskResultListener: BackgroundTaskResultListener? = null


    //--------------------------------------------------------------------------------/

    init {
        Coroutines.main {
            Log.d(TAG, "init")
            _showProgress.postValue(true)

            products
                .await()
                .observeForever { products ->
                    context.let {
                        _adapter.postValue(ProductAutoCompleteTextViewAdapter(products))
                        _adapter.value?.notifyDataSetChanged()
                        if (products.isNotEmpty())
                            _showProgress.postValue(false)

                    }
                }//observe

        }//main
    }//init

    //--------------------------------------------------------------------------------//


}//Cls