tonnylitao

class RecyclerAdapter<M : RecyclerItem>(

 diffCallback: DiffUtil.ItemCallback<M>,

 @LayoutRes val placeholderId: Int?,

 private val clickListener: Listener? = null
  
) : PagedListAdapter<M, ViewHolder<M>>
  (diffCallback) {

tonnylitao

override fun getItemViewType(position: Int) 
 = requireNotNull(
  getItem(position)?.layoutId ?: placeholderId
 ){
  "item at $position is null"
 }

override fun onCreateViewHolder(
 parent: ViewGroup, 
 viewType: Int) 

tonnylitao

inner class ViewHolder(
 val binding: ViewDataBinding
): RecyclerView.ViewHolder(binding.root)

tonnylitao

override fun onBindViewHolder(
  holder: ViewHolder, 
  position: Int
){
 getItem(position)?.run(holder.binding::bind)
}

} //end of RecyclerAdapter

private fun ViewDataBinding.bind(

tonnylitao

data class User(
    ...
) : RecyclerItem {
    override val layoutId: Int
        get() = R.layout.list_item_user

    override val variableId: Int
        get() = BR.user

    override val dataToBind: Any

tonnylitao

class MainFragment: 
  Fragment(R.layout.fragment_main) {
    
    private val adapter by lazy {
      
      RecyclerAdapter(
        RecyclerItem.diffCallback<User>(),
        R.layout.list_item_user_placeholder
      ) { _, _, item ->
         

tonnylitao

data class Comment(
  ...
) : RecyclerItem {
 ...
}

data class ComplexModel(
  val model: SomeModel
  ...
) : RecyclerItem {

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struct User {
    var name, email: String?
    
    var likeKiwi = false
    
    var travel = false
    var hiking = false
    var reading = false
}

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let mapping = [
  \User.name: nameField,
  \User.email: gmailField,
  \User.address: addressField,

  \User.travel: travelBtn,
  \User.hiking: hikingBtn,
  \User.reading: readingBtn,
]

tonnylitao

extension DataBinding {  

  public func update<Value>(_ keyPath: WritableKeyPath<M, Value>, _ value: Value) {
    model[keyPath: keyPath] = value

    _keyPathViews[keyPath]?.wrappedView?.setValue(value)
  }
}