通用RecyclerView Adapter之VastAdapter

Posted 2022-04-09 码上夏雨

前言

VastAdapter 为你提供了快速构建适合于你的 RecyclerView Adapter 的方式

依赖

点击 VastAdapter 查看源码，欢迎Star，fork，并在issue提出改进意见

implementation 'io.github.sakurajimamaii:VastAdapter:0.0.4'

快速开始

通过下面的示例，你可以快速的将 VastAdapter 运用到你的项目当中

实现 VastAdapterItem` 接口

我们以 AExample 和 BExample 为例:

// getVAdpItemType 方法返回值应该与对应的VH相同
class AExample(
    val data: String,
    var clickEventListener: VAapClickEventListener?,
    var longClickEventListener: VAdpLongClickEventListener?,
):VastAdapterItem 

    override fun setVAapClickEventListener(l: VAapClickEventListener?) 
        clickEventListener = l
    

    override fun getVAapClickEventListener(): VAapClickEventListener? 
        return clickEventListener
    

    override fun setVAdpLongClickEventListener(l: VAdpLongClickEventListener?) 
        longClickEventListener = l
    

    override fun getVAdpLongClickEventListener(): VAdpLongClickEventListener? 
        return longClickEventListener
    

    override fun getVAdpItemType(): String 
        return "person"
    


class BExample(
    val drawable:Int,
    var clickEventListener: VAapClickEventListener?,
    var longClickEventListener: VAdpLongClickEventListener?
) : VastAdapterItem 

    override fun setVAapClickEventListener(l: VAapClickEventListener?) 
        clickEventListener = l
    

    override fun getVAapClickEventListener(): VAapClickEventListener? 
        return clickEventListener
    

    override fun setVAdpLongClickEventListener(l: VAdpLongClickEventListener?) 
        longClickEventListener = l
    

    override fun getVAdpLongClickEventListener(): VAdpLongClickEventListener? 
        return longClickEventListener
    

    override fun getVAdpItemType(): String 
        return "picture"
    

设置对应的ViewHolder，ViewHolder需要继承自BaseVastAdapterVH

// AExample对应的VH
class AViewHolder(itemView: View): BaseVastAdapterVH(itemView) 
    private val tv:TextView

    override fun onBindData(item: VastAdapterItem) 
        super.onBindData(item)
        tv.text = (item as AExample).data
    

    class Factory:BVAdpVHFactory
        override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BaseVastAdapterVH 
            return AViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.item_textview,parent,false))
        

        override fun getVAdpVHType(): String 
            return "person" // 和Item相一致
        
    

    init 
        tv = itemView.findViewById(R.id.text)
    


// BExample对应的VH
class BViewHolder(itemView: View) : BaseVastAdapterVH(itemView) 

    private val iv: ImageView

    override fun onBindData(item: VastAdapterItem) 
        super.onBindData(item)
        iv.setImageResource((item as BExample).drawable)
    

    class Factory : BVAdpVHFactory 

        override fun onCreateViewHolder(
            parent: ViewGroup,
            viewType: Int
        ): BaseVastAdapterVH 
            val inflater = LayoutInflater.from(parent.context)
            val itemView: View = inflater.inflate(R.layout.item_imageview, parent, false)
            return BViewHolder(itemView)
        

        override fun getVAdpVHType(): String 
            return "picture"
        

    

    init 
        iv = itemView.findViewById(R.id.item_image)
    

实现Adapter

class BaseAdapter(
    private val items: MutableList<VastAdapterItem>,
    factories: MutableList<BaseVastAdapterVH.BVAdpVHFactory>
) : BaseVastAdapter(items, factories)

在Activity中使用

// 获取数据源
private val datas:MutableList<VastAdapterItem> = ArrayList()

for(i in 0..10)
    datas.add(AExample(i.toString(),null,null))
    datas.add(BExample(R.drawable.ic_knots,null,null))


// 设置给RecyclerView
adapter = BaseAdapter(datas, mutableListOf(AViewHolder.Factory(), BViewHolder.Factory()))

// dataRv是RecyclerView
dataRv.adapter = adapter
dataRv.layoutManager = LinearLayoutManager(this)

添加点击（或长按）事件

对于列表来说，点击事件是必不可少的，VastAdapter 支持你为列表设置通用点击事件，当然因为你的类实现了 VastAdapterItem 接口，因此你也可以单独为其设定点击事件。

通用点击事件设置

adapter.setOnItemClickListener(object :VastAdapter.OnItemClickListener
            override fun onItemClick(view: View, position: Int) 
                // Something you want to do
            
        )
adapter.setOnItemLongClickListener(object:VastAdapter.OnItemLongClickListener
            override fun onItemLongClick(view: View, position: Int): Boolean 
                // Something you want to do
                return true
            
        )

设置单独点击事件

注意，如果你为某一项单独定义了点击事件，那么他不再支持通用点击事件。

// 设置点击事件
private val click = object :VAapClickEventListener
        override fun vAapClickEvent(view: View, pos: Int) 
            showShortMsg("Click event and pos is $pos.")
        
    

// 设置长按事件
private val longClick = object :VAdpLongClickEventListener
        override fun vAdpLongClickEvent(view: View, pos: Int): Boolean 
            showShortMsg("Long click event and pos is $pos.")
            return true
        
    

// 在设置数据源的时候设置
for(i in 0..10)
    datas.add(AExample(i.toString(),click,null))
    datas.add(BExample(R.drawable.ic_knots,null,longClick))

添加新的数据类型

如果你想向列表中添加第三种类型的数据，你只需要以下三步：

• 定义新的数据类型，例如CExample，并使其实现VastAdapterItem接口

• 定义CExample对应的ViewHolder，例如CViewHolder

• 将其对应的Factory添加到adapter中

  adapter = BaseAdapter(datas, mutableListOf(AViewHolder.Factory(), BViewHolder.Factory() ,CViewHolder.Factory()))
  

为Adapter添加其他功能

下面的示例向你展示了为Adapter增加判断数据源是否为空的功能

class BaseAdapter(
    private val items: MutableList<VastAdapterItem>,
    factories: MutableList<BaseVastAdapterVH.BVAdpVHFactory>
) : BaseVastAdapter(items, factories) 

    /**
     * 如果集合为空（不包含任何元素），则返回true，否则返回false。
     * @return Boolean
     */
    fun isItemEmpty() = items.isEmpty()

当然你也可以参考示例应用

引用

BaseVastAdapter部分设计参考自彻底解耦 RecyclerView.Adapter