RecyclerView 简单使用

仓库地址 https://gitee.com/BigObj/bo-an-poj-common

一、需求及规范

1、需求

RecyclerView 是我们常用的列表控件，直接使用时通常大量代码编写于 Adapter 中，当 item 包含视图类型过多时，Adapter 会臃肿不堪，故需要将各个类型视图单独定义编写。

2、规范

主要定义五个模块：adapter、viewHolder、viewHolderFactory、itemView、model

adapter：及 RecyclerView.Adapter 适配器，用来整合填充数据
viewHolder：及 RecyclerView.ViewHolder 视图固定器，用来实现视图重用
viewHolderFactory：创建 viewHolder，并实现多类型视图设置
itemView：item视图代码编写
model：定义公共model，便于使用

二、代码编写

RecyclerViewAdapter

abstract class RecyclerViewAdapter(private var context: Context) :
  RecyclerView.Adapter>>() {

  private val dataList: MutableList by lazy {
      ArrayList()
  }

fun addAllDataList(dataList: List) {
    this.dataList.addAll(dataList)
    notifyDataSetChanged()
}

fun addAllSpaceArray(sparseArray: SparseArray) {
    viewHolderFactory.spaceArray.putAll(sparseArray)
    notifyDataSetChanged()
}

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

override fun onCreateViewHolder(
    parent: ViewGroup,
    viewType: Int
): RecyclerViewHolder> {
    return viewHolderFactory.createViewHolder(context, parent, viewType)
}

protected abstract val viewHolderFactory: ViewHolderFactory

fun getItem(position: Int): M {
    return dataList[position]
}

override fun onBindViewHolder(
    holder: RecyclerViewHolder>,
    position: Int
) {
    holder.itemRecyclerView.dataBinding(dataList[position], position)
}

override fun onAttachedToRecyclerView(recyclerView: RecyclerView) {
    super.onAttachedToRecyclerView(recyclerView)
    recyclerView.addItemDecoration(RecyclerItemDecoration(viewHolderFactory.spaceArray))

  }
} 

RecyclerViewHolder

class RecyclerViewHolder>(var itemRecyclerView: V)
    : RecyclerView.ViewHolder(itemRecyclerView.rootView)

ViewHolderFactory

abstract class ViewHolderFactory {
    abstract fun createViewHolder(context: Context, parent: ViewGroup, viewType: Int):
            RecyclerViewHolder>
}

ItemRecyclerView

abstract class ItemRecyclerView(context: Context, parent: ViewGroup) {

    val binding: VDB by lazy {
        DataBindingUtil.inflate(LayoutInflater.from(context), getItemLayoutId(), parent, false) as VDB
    }

    val viewHolder: RecyclerViewHolder> by lazy {
        RecyclerViewHolder(this)
    }

    val rootView: View by lazy {
        binding.root
    }

    abstract fun dataBinding(m: M, position: Int)

    abstract fun getItemLayoutId(): Int
}

RecyclerViewModel

abstract class RecyclerViewModel

三、使用

DemoViewHolderFactory

class DemoViewHolderFactory: ViewHolderFactory() {
    override fun createViewHolder(
        context: Context,
        parent: ViewGroup,
        viewType: Int
    ): RecyclerViewHolder {
        return DemoItemView(context, parent).viewHolder
    }
}

DemoItemView

class DemoItemView(context: Context, parent: ViewGroup):     ItemRecyclerView(context, parent) {
    override fun dataBinding(m: DemoModel, position: Int) {
        binding.demo = m
    }

    override fun getItemLayoutId(): Int {
        return R.layout.item_demo
    }
}

DemoModel

class DemoModel: RecyclerViewModel() {
    var title: String? = null
    var content: String? = null
}

DemoAdapter

class DemoAdapter(context: Context): RecyclerViewAdapter(context) {
    override fun createViewHolderFactory(): ViewHolderFactory {
        return DemoViewHolderFactory()
    }
}

MainActivity

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val binding: ActivityMainBinding = DataBindingUtil.setContentView(this, R.layout.activity_main)
        binding.demoListView.layoutManager = LinearLayoutManager(this)
        val adapter = DemoAdapter(this)
        binding.demoListView.adapter = adapter

        val dataList = ArrayList()
        for (i in 0..20) {
            val data = DemoModel()
            data.title = "title $i"
            data.content = "content $i"
            dataList.add(data)
        }

        adapter.addAllDataList(dataList)
    }
}

activity_main

item_demo