孟老板 ListAdapter封装, 告别Adapter代码 (中)

2023-12-17 09:42:15

ListAdapter封装 (中) - 多条目, 头尾, 嵌套, 单多选.

前言:

上一篇文章已经讲解 SimpleAdapter 的基本封装. 这次我们将用 ConcatAdapter 封装头尾, 并封装多类型Adapter, 嵌套RecycleView, 单多选Adapter;

class EndAdapter(val view: View) : RecyclerView.Adapter<EndHolder>(){
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) = EndHolder(view)
    override fun onBindViewHolder(holder: EndHolder, position: Int) {}
    override fun getItemCount() = 1
}

class EndHolder(itemView: View) : RecyclerView.ViewHolder(itemView)

1.3 在我们的 BaseAdapter加入:

withHeaderAndFooter() 传入头尾View 就OK了;

/**
 * 组装头尾, 返回一个新的 ConcatAdapter 实体, 需要将新实体设置给 RecycleView
 */
fun withHeaderAndFooter(
    header: View? = null,
    footer: View? = null
) = when{
        header != null && footer != null -> ConcatAdapter(EndAdapter(header), this, EndAdapter(footer))
        header != null && footer == null -> ConcatAdapter(EndAdapter(header), this)
        header == null && footer != null -> ConcatAdapter(this, EndAdapter(footer))
        else -> this
    }

1.4 使用:

只需要将 withHeaderAndFooter() 返回的 Adapter 赋给 RecycleView即可, 我们还是操作主Adapter

val headBinding = ViewHeaderTjBinding.inflate(LayoutInflater.from(mActivity), mView as @Nullable ViewGroup, false)

//主数据 Adapter
mAdapter = MultipleAdapter()

//将这个由 withHeaderAndFooter() 返回的 ConcatAdapter 赋给 RecycleView 即可
val mmAdapter = mAdapter.withHeaderAndFooter(headBinding.root)
mDataBind.rvRecycle.let {
    it.layoutManager = LinearLayoutManager(mActivity)
    it.adapter = mmAdapter
}

2. BaseAdapter 改造, 传入实体泛型;

2.1 首先 DiffCallback 必须要用泛型改造;

class DiffCallback<T : BaseItem>: DiffUtil.ItemCallback<T>() {
    /**
     * 比较两个条目对象  是否为同一个Item
     */
    override fun areItemsTheSame(oldItem: T, newItem: T): Boolean {
        return oldItem === newItem
    }

    /**
     * 再确定为同一条目的情况下;  再去比较 item 的内容是否发生变化;
     * 我们使用 状态标识方式判断;
     * @return true: 代表无变化;  false: 有变化;
     */
    override fun areContentsTheSame(oldItem: T, newItem: T): Boolean {
        return !oldItem.hasChanged
    }
}

2.2 在 BaseAdapter 中加入方便本地操作的增删改方法; 最终代码如下

abstract class BaseAdapter<T: BaseItem>(
    protected val handler: BaseHandler? = null) :
    ListAdapter<T, NewViewHolder>(DiffCallback()) {

    override fun onBindViewHolder(holder: NewViewHolder, position: Int) {
        holder.bind(getItem(position))
    }

    /**
     * 重写 提交数据方法, 让它必定以新数据集合对象传入
     */
    override fun submitList(list: MutableList<out T>?) {
        val newData = mutableListOf<T>()
        if(list != null){
            newData.addAll(list)
        }
        super.submitList(newData)
    }

    /**
     * 删除指定条目
     */
    fun remove(entity: BaseItem){
        removeAt(currentList.indexOf(entity))
    }
    fun removeAt(position: Int){
        if(position == -1) return
        if(position >= currentList.size) return
        val newData = mutableListOf<T>()
        newData.addAll(currentList)
        newData.removeAt(position)
        super.submitList(newData)
    }


    /**
     * 修改指定条目
     */
    fun update(entity: T){
        updateAt(currentList.indexOf(entity))
    }
    fun updateAt(position: Int){
        if(position == -1) return
        if(position >= currentList.size) return
        notifyItemChanged(position)
    }

    /**
     * 新增条目
     */
    fun insert(entity: T, position: Int = -1){
        val newData = mutableListOf<T>()
        newData.addAll(currentList)

        if(position < newData.size && position >= 0){
            newData.add(position, entity)
        }else{
            newData.add(entity)
        }
        super.submitList(newData)
    }


    /**
     * 组装头尾, 返回一个新的 ConcatAdapter 实体, 需要将新实体设置给 RecycleView
     */
    fun withHeaderAndFooter(
        header: View? = null,
        footer: View? = null
    ) = when{
            header != null && footer != null -> ConcatAdapter(EndAdapter(header), this, EndAdapter(footer))
            header != null && footer == null -> ConcatAdapter(EndAdapter(header), this)
            header == null && footer != null -> ConcatAdapter(this, EndAdapter(footer))
            else -> this
        }
}

2.3 SimpleAdapter 只需要改成继承 BaseAdapter<BaseItem> 即可;

open class SimpleAdapter(
    private val layout: Int,
    handler: BaseHandler? = null
) : BaseAdapter<BaseItem>(handler)

3. 多条目类型 MultipleAdapter

多类型其实是很简单的, 还是重写 getItemViewType();

有区别的是, getItemViewType() 的返回值, 直接返回布局文件ID. 然后实体类自行判断给出 LayoutId

3.1 实体类:

还是实现 BaseItem, 重写 getMItemType() , 返回布局文件 ID

class MultipleEntity(
    var name: String,
    var index: Int = 0,
    override var hasChanged: Boolean = false)
    : BaseItem {

    /**
     * 实体类自行判断, 并给出 布局id
     */
    override fun getMItemType(): Int {
        return if(index % 2 == 0){
            R.layout.item_multiple_one
        }else{
            R.layout.item_multiple_two
        }
    }
}

3.2 MultipleAdapter:

需要重写 getItemViewType() 并将实体类的 getMItemType() 结果返回;

创建 ViewHolder 的时候, 直接用 viewType 作为布局ID (因为我们用布局ID做的ViewType)

/**
 * 多条目 类型 Adapter;
 * 1.实体类需要重写  {@link BaseItem} 的 getMItemType() 方法; 并根据类型,返回不同的 LayoutId
 * 2.复杂 Adapter. 还需要自定义;  继承 MultipleAdapter 并重写 getItemViewType()
 */
open class MultipleAdapter(handler: BaseHandler? = null) :
    BaseAdapter<BaseItem>(handler) {

    /**
     * Item类型, 同 layoutId;
     */
    override fun getItemViewType(position: Int): Int {
        return currentList[position].getMItemType()
    }

    /**
     * viewType 同 layoutId
     */
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): NewViewHolder {
        if(viewType == 0) throw RuntimeException("Undefined itemViewType")
        return NewViewHolder(
            DataBindingUtil.inflate(
                LayoutInflater.from(parent.context),
                viewType, parent, false
            ), handler
        )
    }
}

3.3 接下来就是用了;

很简单是不是, 直接把数据集合塞进Adapter里就完事了

mAdapter = MultipleAdapter()

mDataBind.rvRecycle.let {
    it.layoutManager = LinearLayoutManager(mActivity)
    it.adapter = mAdapter
}

val data = mutableListOf<MultipleEntity>()
repeat(30){
    if(it % 2 == 0){
        data.add(MultipleEntity("小美", it))
    }else{
        data.add(MultipleEntity("小状", it))
    }
}
mAdapter.submitList(data)

3.4 布局文件也帖出来吧

item_multiple_one.xml
<layout>
    <data>
        <variable
            name="item"
            type="com.example.kotlinmvpframe.yiyou.entity.MultipleEntity" />
    </data>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:padding="12dp">
    <TextView
        style="@style/tv_base_16_dark"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text='@{item.name + "  我是类型one,我有靓照"}'
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"/>
    <ImageView
        style="@style/img_wrap"
        android:layout_width="60dp"
        android:layout_height="50dp"
        android:src="@drawable/bg"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>


item_multiple_two.xml
<layout>
    <data>
        <variable
            name="item"
            type="com.example.kotlinmvpframe.yiyou.entity.MultipleEntity" />
    </data>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:padding="12dp">
    <TextView
        style="@style/tv_base_16_dark"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text='@{item.name + "  我是类型two,我有money"}'
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"/>
    <TextView
        style="@style/tv_base_16_dark"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textStyle="italic|bold"
        android:textColor="@color/shape_red"
        android:text="¥. 500"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>

3.5 再贴上效果图 : [奸笑]

4. 嵌套 NestedAdapter

4.1 嵌套 RecycleView 的注意点:

嵌套子层数据集合: 一般在外层实体中; 例如一条朋友圈中多张图片. 外层实体持有 Image集合; 我们就用接口的方式, 规范这个集合

子层RecycleView: 如果固定的 ViewDataBinding 对象, 我们可以直接拿它的 RecycleVIew. 但是它不固定咋办? 也没法封装继承啊! 好吧, 好办 [机智]

子层的 Adapter: 这个好办, 上一篇我们已经封装好了 SimpleAdapter;

子层列表事件: 子层的事件, 还是用 handler 处理, 但最终由回调函数,调到主界面处理;

4.2 思路

首先外层列表的主数据绑定, 没有变化, 还是用总的 ViewHolder.bind() 方式;

其次我们规范嵌套子层 RecycleView 的ID, 用 findViewById 的方式把它存到 ViewHolder 里;

实体类实现 BaseNestedItem 接口的 getNestedList() 函数; 把子层集合返回;

4.3 上代码:

/**
 * 单条目, 简单Item MVVM Adapter
 * 复杂类型 还是得自定义 Adapter
 */
open class NestedAdapter<T: BaseNestedItem>(
    /**
     * 外层列表 item布局;
     */
    private val layout: Int,
    /**
     * 内层列表 item布局;
     */
    private val nestedLayoutId: Int,
    /**
     * 生成子层Recycle的 LayoutManager; 可以是 LinearLayoutManager GridLayoutManager 等;
     * 默认 横向 LinearLayoutManager
     */
    private val childLayoutManager: (() -> RecyclerView.LayoutManager)? = null,
    /**
     * 子层列表点击回调; 此方式可能不太优雅. 有待改进
     * arg1 子层点击 View
     * arg2 外层点击 position;  这个position并不保险; 当存在 Header 时, 它需要 -1
     * arg3 子层实体对象
     */
    private val childClickListener: ((View, Int, BaseItem) -> Unit)? = null,
    /**
     * 外层类表点击事件;
     */
    handler: BaseHandler? = null

) :
    BaseAdapter(handler) {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): NewViewHolder {
        val bingding: ViewDataBinding = DataBindingUtil.inflate(LayoutInflater.from(parent.context), layout, parent, false)
        // 统一规范 子层 RecycleView 的id;  将 RecyclerView 存入 NestedHolder
        val rvNested = bingding.root.findViewById<RecyclerView>(R.id.rv_nested_item)
        return NestedHolder(rvNested, bingding, handler)
    }

    override fun onBindViewHolder(holder: NewViewHolder, position: Int) {
        if(holder is NestedHolder){
            //绑定子层 Recycle Adapter
            createNestedAdapter(holder)
            //绑定子层 数据
            (holder.rvNested?.adapter as SimpleAdapter?)?.submitList(getItem(position).getNestedList())
        }
        super.onBindViewHolder(holder, position)
    }

    /**
     * 绑定子层 Recycle 的 Adapter
     */
    private fun createNestedAdapter(holder: NestedHolder) {
        holder.rvNested?.let {
            if(it.adapter == null){
                //子层点击事件;  null 则不设置;
                val handler = if(childClickListener == null){
                    null
                }else{
                    object : Handler<BaseItem>(){
                        override fun onClick(view: View, info: BaseItem) {
                            childClickListener.invoke(view, holder.layoutPosition, info)
                        }
                    }
                }
                val adapter = SimpleAdapter(nestedLayoutId, handler)
                it.layoutManager = childLayoutManager?.invoke() ?: LinearLayoutManager(it.context, RecyclerView.HORIZONTAL, false)
                it.adapter = adapter
            }
        }
    }

    /**
     * 重写 ViewHoleder,  附带 RecyclerView
     */
    class NestedHolder(val rvNested: RecyclerView?, binding: ViewDataBinding, handler: BaseHandler?) : NewViewHolder(binding, handler)
}

4.4 讲解:

可以看出, NestedAdapter 的内外层布局 ID直接传入; 内层 LayoutManager, 及事件响应由kotlin高阶函数提供;

注意: 内层事件响应时, 回调给了外层position 是通过 holder.layoutPosition; 但是在有头部的Adapter中 layoutPosition 是需要 -1 的;

还有一个 holder.bindingAdapterPosition 参数, 但是它在带头部的ConcatAdapter 中使用时, 经常返回 -1; 不知道是不是博主使用姿势不对;

4.5 BaseNestedItem: getNestedList() 函数统一规范子集合;

interface BaseNestedItem : BaseItem{
    fun getNestedList(): MutableList<out BaseItem>?
}

4.6 实体类:

class MultipleEntity(
    var name: String,
    override var hasChanged: Boolean = false)
    : BaseNestedItem {

    var imgs: MutableList<ImageEntity>? = null
    
    // 返回子层集合
    override fun getNestedList(): MutableList<ImageEntity>? = imgs

    /**
     * 子层集合实体类
     */
    class ImageEntity(val res: Int, override var hasChanged: Boolean = false) : BaseItem
}

4.7 使用:

mAdapter = NestedAdapter<MultipleEntity>(
    //主列表布局 ID
    R.layout.item_nested_one,
    //子列表布局 ID
    R.layout.item_img,
    //事件响应
    childClickListener = {
        _, layoutPosition, info ->
        val childIndex = (mAdapter.currentList[layoutPosition] as MultipleEntity).imgs?.indexOf(info) ?: 0
        Toast.makeText(mActivity.applicationContext, "点击了第${layoutPosition + 1} 的第${childIndex + 1}个条目", Toast.LENGTH_SHORT).show()
})
mDataBind.rvRecycle.let {
    it.layoutManager = LinearLayoutManager(mActivity)
    it.adapter = mAdapter
}

val data = mutableListOf<MultipleEntity>()
repeat(5){
    val entity = if(it % 2 == 0){
        MultipleEntity("小美", it)
    }else{
        MultipleEntity("小状", it)
    }
    entity.imgs = mutableListOf(
        ImageEntity(R.drawable.bg), ImageEntity(R.drawable.bg), ImageEntity(R.drawable.bg), ImageEntity(R.drawable.bg),
        ImageEntity(R.drawable.bg), ImageEntity(R.drawable.bg), ImageEntity(R.drawable.bg), ImageEntity(R.drawable.bg))
    data.add(entity)
}
mAdapter.submitList(data)

4.8 布局贴出来

item_nested_one.xml
<layout>
    <data>
        <variable
            name="item"
            type="com.example.kotlinmvpframe.yiyou.entity.MultipleEntity" />
    </data>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:padding="12dp">
    <TextView
        android:id="@+id/tv_name_item"
        style="@style/tv_base_16_dark"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text='@{item.name}'
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"/>
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv_nested_item"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        app:layout_constraintTop_toBottomOf="@id/tv_name_item"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>


item_img.xml
<layout>
    <data>
        <variable
            name="item"
            type="com.example.kotlinmvpframe.yiyou.entity.MultipleEntity.ImageEntity" />
        <variable
            name="handler"
            type="com.example.kotlinmvpframe.test.testtwo.Handler" />
    </data>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="@{v -> handler.onClick(v, item)}"
    android:padding="8dp">
    <ImageView
        style="@style/img_wrap"
        android:layout_width="80dp"
        android:layout_height="80dp"
        app:imgRes="@{item.res}"/>
</FrameLayout>
</layout>

4.9 效果图来了:

5. SingleChoiceAdapter 单选

5.1 分析:

实体需要有 checked 字段, 我们用 BaseCheckedItem 作为实体基类
规范布局文件中 CheckBox 的 ID, onCreateViewHolder 时通过 findViewById 将控件保存到 ViewHolder
选中某个条目时, 之前选中的条目需要反选. 所以必须要知道上一次选中的实体和CheckBox
监听 onCheckedChanged 事件, 新实体选中, 就实体反选.
单选时, 不允许反选, 此时不用 CheckBox, 而用 RadioButton

5.2 BaseCheckedItem

它是 BaseItem 的实现类, 并增加了 hasChecked 字段

/**
 * 普通单多选列表 实体类
 */
interface BaseCheckedItem : BaseItem{
    var hasChecked: Boolean     // 是否被勾选中
}

5.3 实体类

class CheckEntity(
    var name: String? = null,
    override var hasChecked: Boolean = false,
    override var hasChanged: Boolean = false)
    : BaseCheckedItem

5.4 重点来了: SingleChoiceAdapter

直接上代码吧, 已经写了注释

class SingleChoiceAdapter<T : BaseCheckedItem>(
    /**
     * 布局id;
     */
    private val layout: Int,
    handler: BaseHandler? = null
): BaseAdapter<T>(handler), CompoundButton.OnCheckedChangeListener {
    //弱引用,  当选中条目被删除时, 应当释放资源
    var wearEntity: WeakReference<T>? = null
    var wearView: WeakReference<CompoundButton>? = null

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): NewViewHolder {
        val bingding: ViewDataBinding = DataBindingUtil.inflate(LayoutInflater.from(parent.context), layout, parent, false)
        // 统一规范 CheckBox 的id;  将 RecyclerView 存入 ChoiceHolder
        val cbCheck = bingding.root.findViewById<CompoundButton>(R.id.cb_check_item)
        return ChoiceHolder(cbCheck, bingding, handler)
    }

    override fun onBindViewHolder(holder: NewViewHolder, position: Int) {
        if(holder is ChoiceHolder){
            val entity = currentList[position]
            if(entity.hasChecked){
                wearEntity = WeakReference(entity)
                wearView = WeakReference(holder.cbCheck)
            }
            //用 tag 将对象实体存储;
            holder.cbCheck?.tag = entity
            holder.cbCheck?.setOnCheckedChangeListener(this)

            //这一行是测试用的, 应当删掉
            (entity as CheckEntity).name = Integer.toHexString(holder.cbCheck?.hashCode() ?: 0)
        }
        super.onBindViewHolder(holder, position)
    }

    /**
     * checkbox 选中事件
     */
    override fun onCheckedChanged(buttonView: CompoundButton?, isChecked: Boolean) {
        //判断是否是 手动操作
        if(buttonView?.isPressed == true){
            Log.d("pppppppppppppppppp", "手动操作了 ChekcBox")

            wearEntity?.let {
                it.get()?.hasChecked = false
                it.clear()
            }

            // 因 RecycleView 复用机制, 这里新旧 Button 可能为同一个;
            // 当同一个button 时, 不需要重置原button 的选中状态;  不需要重新 new WeakReference
            val isSameBtn = buttonView == wearView?.get()
            if(!isSameBtn){
                wearView?.let {
                    it.get()?.isChecked = false
                    it.clear()
                }
                wearView = WeakReference(buttonView)
            }

            val entity = buttonView.tag as T?
            entity?.hasChecked = true
            wearEntity = WeakReference(entity)
        }
    }


    /**
     * 重写 ViewHoleder,  附带 ImageView;  勾选是使用 ImageView 切换图片的方式
     */
    class ChoiceHolder(val cbCheck: CompoundButton?, binding: ViewDataBinding, handler: BaseHandler?) : NewViewHolder(binding, handler)
}

5.5 布局文件: item_test_choise

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

    <data>
        <variable
            name="item"
            type="com.example.kotlinmvpframe.yiyou.entity.CheckEntity" />

        <variable
            name="handler"
            type="com.example.kotlinmvpframe.test.testtwo.Handler" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <TextView
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:layout_marginStart="20dp"
            android:text="@{item.name}"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent"/>
        <RadioButton
            android:id="@+id/cb_check_item"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:drawableEnd="@drawable/checkbox_selector"
            android:padding="24dp"
            android:background="@null"
            android:button="@null"
            android:checked="@{item.hasChecked}"
            app:layout_constraintTop_toTopOf="parent"/>
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

5.6 使用:

很简单, 只需要初始化 Adapter, RecycleView; 并设置数据源即可

mAdapter = SingleChoiceAdapter(R.layout.item_test_choise)
mDataBind.rvRecycle.let {
    it.layoutManager = LinearLayoutManager(mActivity)
    it.adapter = mAdapter
}

val data = mutableListOf<CheckEntity>()
repeat(15){
    data.add(CheckEntity("小华"))
}
mAdapter.submitList(data)


//以下, 没用
mDataBind.btnLeft.setOnClickListener {
    val entity = mAdapter.wearEntity?.get()
    if(entity == null){
        Toast.makeText(mActivity, "当前未选中", Toast.LENGTH_SHORT).show()
        return@setOnClickListener
    }

    val position = mAdapter.currentList.indexOf(entity)
    Toast.makeText(mActivity, "当前选中${entity.name}, index=${position}", Toast.LENGTH_SHORT).show()
}
mDataBind.btnRight.setOnClickListener {
    mAdapter.notifyDataSetChanged()
}

5.7 效果图:

6. MultipleChoiceAdapter 多选

多选就简单了; 注意, 需要将 item_test_choise 中的 RadioButton 换成 CheckBox

6.1 直接上代码:

class MultipleChoiceAdapter<T : BaseCheckedItem>(
    /**
     * 布局id;
     */
    private val layout: Int,
    handler: BaseHandler? = null
): BaseAdapter<T>(handler), CompoundButton.OnCheckedChangeListener {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): NewViewHolder {
        val bingding: ViewDataBinding = DataBindingUtil.inflate(LayoutInflater.from(parent.context), layout, parent, false)
        // 统一规范 CheckBox 的id;  将 RecyclerView 存入 NestedHolder
        val cbCheck = bingding.root.findViewById<CompoundButton>(R.id.cb_check_item)
        return SingleChoiceAdapter.ChoiceHolder(cbCheck, bingding, handler)
    }

    override fun onBindViewHolder(holder: NewViewHolder, position: Int) {
        if(holder is SingleChoiceAdapter.ChoiceHolder){
            val entity = currentList[position]
            holder.cbCheck?.tag = entity
            holder.cbCheck?.setOnCheckedChangeListener(this)
        }
        super.onBindViewHolder(holder, position)
    }

    /**
     * checkbox 选中事件
     */
    override fun onCheckedChanged(buttonView: CompoundButton?, isChecked: Boolean) {
        //判断是否是 手动操作
        if(buttonView?.isPressed == true){
            val entity = buttonView.tag as T?
            entity?.hasChecked = isChecked
        }
    }
}

6.2 使用跟单选Adapter一样, 初始化RecycleVIew, 设置数据源即可;

遍历的话这样:

val list = mAdapter.currentList.filter {
    it.hasChecked
}
Toast.makeText(mActivity, "当前选中${list.size}条", Toast.LENGTH_SHORT).show()

6.3 效果图

好的! 终于 over

回到顶部

码农公寓

孟老板 ListAdapter封装, 告别Adapter代码 (中)

ListAdapter封装 (中) - 多条目, 头尾, 嵌套, 单多选.

前言:

目录:

1.用 ConcatAdapter 封装头尾;

2. BaseAdapter 改造, 传入实体泛型;

3. 多条目类型 MultipleAdapter

4. 嵌套 NestedAdapter

5. SingleChoiceAdapter 单选

6. MultipleChoiceAdapter 多选

码农公寓

ListAdapter封装 (中) - 多条目, 头尾, 嵌套, 单多选.

前言:

目录:

1.用 ConcatAdapter 封装头尾;

2. BaseAdapter 改造, 传入实体泛型;

3. 多条目类型 MultipleAdapter

4. 嵌套 NestedAdapter

5. SingleChoiceAdapter 单选

6. MultipleChoiceAdapter 多选

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