RecyclerView 有多個不同的樣式的View ，稱為 multiple view type

使用 data class 改成可支援多種情境 sealed class

sealed class Todo(val viewType: Int) {
    data class Title(val text: String) : Todo(TYPE_TITLE)
    data class Item(
        val name: String,
        val checked: Boolean
    ) : Todo(TYPE_ITEM)

    companion object {
        const val TYPE_TITLE = 0
        const val TYPE_ITEM = 1
    }
}

Adapter 改成使用 RecyclerView.ViewHolder

class TodoAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {

    private var todos = listOf<Todo>()

   //依 position 取得 view type 
    override fun getItemViewType(position: Int): Int {
        return todos[position].viewType
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
    
    // 依  viewType 呼叫 ViewHolder
        return when (viewType) {
            Todo.TYPE_TITLE -> TodoTitleViewHolder(parent)
            else -> TodoViewHolder(parent)
        }
    }

    override fun getItemCount(): Int {
        return todos.size
    }
    
       //依 position 取得 view type  來綁定 ViewHolder
    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        when (val todo = todos[position]) {
            is Todo.Title -> (holder as TodoTitleViewHolder).bind(todo)
            is Todo.Item -> (holder as TodoViewHolder).bind(todo)
        }
    }
    fun refresh(todos: List<Todo>) {
        this.todos = todos
        notifyDataSetChanged()
    }
   
}

最後呼叫adapter refresh 更新 RecyclerView data

 val adapter = TodoAdapter()
 recyclerView.adapter = adapter
  .......
 adapter.refresh(
            listOf(
                Todo.Title("聯絡人1"),
                Todo.Item( "Allen",false),
                Todo.Item("Bear", false)
                Todo.Item("Mary", false),
                Todo.Item("Sandy", false),
                Todo.Title("聯絡人2"),
                Todo.Item("Ray", false),
                Todo.Item("Vic", false)
            )
        )

reference:https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.ViewHolder

reference:https://www.notion.so/RecyclerView-8-26-Andy-b0d303838fe0425a95d8ba2d4cf89727