binding.list.addAll不适用于数据绑定,也使用binding.executePendingBindings,但用户界面未更新

如何解决binding.list.addAll不适用于数据绑定,也使用binding.executePendingBindings,但用户界面未更新

我是数据绑定的新手。我的例子很简单,我在recyclerview中添加了一些静态数据,并且在单击按钮一段时间后,我在recyclerview中添加了其他数据,

所以,第一次列表大小为0时,它工作正常,第二次添加数据,我将addAll()executePendingBindings()一起使用,但不会在ui中反映新数据。

if(binding.list?.size==0){ 
binding.list = it 
}else{ 
binding.list?.addAll(it) 
}
binding.executePendingBindings()

所以,但是如果我使用,那么没有executePendingBinding()

也可以
if(binding.list?.size==0){
binding.list = it
}else{
var old_newdata:ArrayList<Person> = (binding?.list!!+it) as ArrayList<Person>
binding.list = old_newdata
}

那是为什么?我不明白为什么不使用addAll()和executependingbinding()?

MainActivity.kt:

class MainActivity : AppCompatActivity(),ListActionHandler {
    
        private val binding by lazy { ActivityMainBinding.inflate(layoutInflater) }
        private lateinit var viewModel: MainViewModel
    
        override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            setContentView(binding.root)
    
            viewModel = ViewModelProviders.of(this).get(MainViewModel::class.java)
    
            binding.viewModel = viewModel
            binding.list = ArrayList()
            binding.itemclickHandler = this
            startObserving()
        }
    
        private fun startObserving() {
            Handler().postDelayed(Runnable {
    
                var mutableList = ArrayList<Person>()
    
                mutableList.add(Person("Mansi Shah","User001",""))
                mutableList.add(Person("Muuni Shah","User002",1,""))
                mutableList.add(Person("Alpa Shah","User003",""))
                mutableList.add(Person("Solani Shah","User004",""))
                mutableList.add(Person("Menka Shah","User005",""))
                mutableList.add(Person("Misri Shah","User006",""))
                mutableList.add(Person("Moti Shah","User007",""))
                mutableList.add(Person("Khevana Shah","User008",""))
    
                //binding.list?.addAll(mutableList)
                viewModel.setListData(mutableList)
    
            },10000)
    
            viewModel.mutablelistData?.observe(this,Observer {
    
                it?.let {
                    //binding.list = it
                    if (binding.list?.size == 0) {
                        binding.list = it
                    } else {
                        // todo: working without execute binding and without addAll,but with =
                        // var old_newdata:ArrayList<Person> = (binding?.list!!+it) as ArrayList<Person>
                        //  binding.list = old_newdata
    
                        //todo : Not working with execute binding,so need to notify adapter
                        //binding.list?.addAll(it)
                        //binding.executePendingBindings()
    
                        val startposition = binding.list!!.size
                        binding.list?.addAll(it)
                        binding.rvPerson.adapter?.notifyItemRangeChanged(startposition,it.size)
    
                    }
    
                }
            })
        }
    
        override fun btnClick(position: Int) {
            val item = binding.list?.get(position)
    
            item?.let {
    
                when (item.follow_status) {
                    0 -> {
                        val item1 = binding.list?.get(position)?.copy(follow_status = 1)
                        viewModel.mutablelistData.value?.set(position,item1!!)
                        binding.rvPerson.adapter?.notifyItemChanged(position,item1!!)
                        //binding.rvPerson.adapter?.notifyDataSetChanged()
                    }
                    1 -> {
                        val item1 = binding.list?.get(position)?.copy(follow_status = 0)
                        viewModel.mutablelistData.value?.set(position,item1!!)
                        // viewModel.mutablelistData.value?.set(position,item1!!)
                    }
                    else -> {
                        val item1 = binding.list?.get(position)?.copy(follow_status = 0)
                        viewModel.mutablelistData.value?.set(position,item1!!)
                    }
                }
            }
        }
    
        override fun btnAddClick() {
            var mutableList = ArrayList<Person>()
    
            mutableList.add(Person("Denma Shah","User009",""))
            mutableList.add(Person("Irish Shah","User0010",""))
            mutableList.add(Person("Mangolia Shah","User0011",""))
            mutableList.add(Person("Lily Shah","User0012",""))
            mutableList.add(Person("Bloom Shah","User0013",""))
            mutableList.add(Person("Iva Shah","User0014",""))
            mutableList.add(Person("Ishika Shah","User0015",""))
            mutableList.add(Person("Oliver Shah","User0016",""))
    
            //old data
            // mutableList.addAll(viewModel.getListData())
            viewModel.setListData(mutableList)
        }
    }

activity_main.xml

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

    <data>

        <import type="android.view.View" />

        <import type="java.util.ArrayList"/>

        <variable
            name="viewModel"
            type="com.example.databindingdemo.viewmodel.MainViewModel" />

        <variable
            name="list"
            type="ArrayList&lt;com.example.databindingdemo.model.Person&gt;" />

        <variable
            name="itemclickHandler"
            type="com.example.databindingdemo.actionhandler.ListActionHandler" />

    </data>


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

        <androidx.appcompat.widget.AppCompatButton
            android:id="@+id/btnAdd"
            style="@style/buttonTheme"
            android:background="@color/colorPrimaryDark"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:onClick="@{(v)->itemclickHandler.btnAddClick()}"
            android:text="ADD"/>


        <androidx.appcompat.widget.AppCompatButton
            android:id="@+id/btnNext"
            style="@style/buttonTheme"
            android:background="@color/colorPrimaryDark"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:text="Next"/>
        
        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/rvPerson"
            app:layout_constraintTop_toBottomOf="@+id/btnAdd"
            app:layout_constraintBottom_toBottomOf="parent"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:orientation="vertical"
            bind:list="@{list}"
            bind:clickHandler="@{itemclickHandler}"
            android:visibility="@{list!=null &amp;&amp; list.size()>0? View.VISIBLE:View.GONE}"
            app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager" />

        <TextView
            android:id="@+id/no_data"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="No Data in List !!!"
            android:visibility="@{list!=null &amp;&amp; list.size()>0? View.GONE:View.VISIBLE}"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

    </androidx.constraintlayout.widget.ConstraintLayout>

</layout>

ListDataAdpater.kt:

class ListDataAdpater(
    private val listData: ArrayList<Person>,private val clickHandler: ListActionHandler
) : RecyclerView.Adapter<ListDataAdpater.ViewHolder>() {

    private var binding: ListItemDataBinding? = null

    inner class ViewHolder(val binding: ListItemDataBinding) :
        RecyclerView.ViewHolder(binding.root) {

        init {
            setIsRecyclable(true)
        }

        fun bind(data: Person) {
            binding?.listItemData = data
            binding?.clickHandler = clickHandler
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup,viewType: Int): ViewHolder {
        binding = ListItemDataBinding.inflate(LayoutInflater.from(parent.context),parent,false)
        return ViewHolder(binding!!)
    }

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

    override fun getItemCount(): Int {
        return listData.size
    }
}

list_item.xml:

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

    <data>

        <import type="android.view.View" />

        <variable
            name="listItemData"
            type="com.example.databindingdemo.model.Person" />

        <variable
            name="clickHandler"
            type="com.example.databindingdemo.actionhandler.ListActionHandler" />

        <variable
            name="position"
            type="int" />

    </data>

    <!--  <LinearLayout
          android:layout_width="match_parent"
          android:layout_height="@dimen/_10sdp"
          android:orientation="vertical"
          android:visibility="gone"/>-->

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@android:color/black"
        android:padding="@dimen/_2sdp">


        <androidx.appcompat.widget.AppCompatImageView
            android:id="@+id/imgUserSeach"
            android:layout_width="@dimen/_58sdp"
            android:layout_height="@dimen/_58sdp"
            android:adjustViewBounds="true"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            bind:roundedCornersRad="@{`3`}"
            bind:url="@{listItemData==null?``:listItemData.url}" />

        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:paddingStart="@dimen/_5sdp"
            android:paddingEnd="@dimen/_5sdp"
            android:weightSum="3"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toEndOf="@+id/imgUserSeach"
            app:layout_constraintTop_toTopOf="parent">

            <RelativeLayout
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_gravity="center_horizontal"
                android:layout_weight="2">

                <androidx.appcompat.widget.AppCompatTextView
                    android:id="@+id/tvUserName"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:ellipsize="end"
                    android:fontFamily="@font/montserrat_medium"
                    android:letterSpacing="0.02"
                    android:lineSpacingExtra="8sp"
                    android:lines="1"
                    android:text="@{listItemData.full_name}"
                    android:textColor="@android:color/white"
                    android:textSize="13.3sp"
                    tools:text="Mansi Shah" />

                <!-- android:onClick="@{(v)->searchItemHandler.onItemClick(searchData)}"-->

                <androidx.appcompat.widget.AppCompatTextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_below="@+id/tvUserName"
                    android:layout_marginTop="@dimen/_8sdp"
                    android:ellipsize="end"
                    android:fontFamily="@font/montserrat_medium"
                    android:letterSpacing="0.02"
                    android:lineSpacingExtra="11.3sp"
                    android:lines="1"
                    android:text="@{listItemData.username}"
                    android:textColor="#80ffffff"
                    android:textSize="10sp"
                    tools:text="User001" />

                <androidx.appcompat.widget.AppCompatCheckBox
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_below="@+id/tvUserName"
                    android:layout_alignParentEnd="true"
                    android:layout_alignParentRight="true" />

            </RelativeLayout>

            <RelativeLayout
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_gravity="center_horizontal"
                android:layout_weight="1">

                <androidx.appcompat.widget.AppCompatTextView
                    android:id="@+id/btnFollow"
                    style="@style/buttonTheme"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_alignParentEnd="true"
                    android:layout_alignParentRight="true"
                    android:layout_centerVertical="true"
                    android:background="@{listItemData.follow_status == 0?@drawable/cyan_button: @drawable/grey_button}"
                    android:ellipsize="end"
                    android:lineSpacingExtra="4.5sp"
                    android:lines="1"
                    android:onClick="@{(v)->clickHandler.btnClick(position)}"
                    android:text="@{listItemData.follow_status == 0? @string/follow : @string/following}" />
            </RelativeLayout>

        </LinearLayout>

        <View
            android:id="@+id/vdivider"
            android:layout_width="match_parent"
            android:layout_height="@dimen/_1sdp"
            android:layout_marginTop="@dimen/_10sdp"
            android:background="#8b9096"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/imgUserSeach" />

    </androidx.constraintlayout.widget.ConstraintLayout>

</layout>

BindAdapters.kt:

@JvmStatic // add this line !!
        @BindingAdapter(value = ["bind:list","bind:clickHandler"],requireAll = false)
        fun bindAdapter(view: RecyclerView,list: ArrayList<Person>?,handler: ListActionHandler) {

            list?.let {
                val adapter = ListDataAdpater(list,handler)
                view.adapter = adapter
            }
        }

解决方法

暂无找到可以解决该程序问题的有效方法,小编努力寻找整理中!

如果你已经找到好的解决方法,欢迎将解决方案带上本链接一起发送给小编。

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