• ListAdapter不需要得到size。因为传入多少数据，它的size默认就是多大。一共需要传入三个类型，一个数据类型，一个ViewHolder，最后一个就是构造函数中的Diffutil，用来局部更新RecyclerView，不需要考虑乱序等问题，也不需要notifichanged，不会影像RecyclerView的性能
    1. // 写一个构造用来给item设置点击事件回调
    2. class LocationAdapter(private val itemClick: (String) -> Unit) :
    3.     ListAdapter<String, LocationAdapter.ViewHolder>(
    4.         object : DiffUtil.ItemCallback<String>() {
    5.             override fun areItemsTheSame(
    6.                 oldItem: String,
    7.                 newItem: String
    8.             ) =
    9.                 oldItem == newItem
    11.             override fun areContentsTheSame(
    12.                 oldItem: String,
    13.                 newItem: String
    14.             ) =
    15.                 oldItem == newItem
    17.         }
    18.     ) {
    19.     inner class ViewHolder(view: LocationItemBinding) : RecyclerView.ViewHolder(view.root) {
    20.         private val title = view.companyName
    21.         val root = view.root
    22.         fun bind(string: String) {
    23.             title.text = string.name_en
    24.         }
    25.     }
    27.     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) = ViewHolder(
    28.         LocationItemBinding.inflate(
    29.             LayoutInflater.from(parent.context),
    30.             parent,
    31.             false
    32.         )
    33.     ).apply {
    34.         root.setOnClickListener {
    35.             itemClick(getItem(absoluteAdapterPosition)) // getItem(index)函数可以拿到Rv中的某一项
    36.         }
    37.     }
    39.     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
    40.         holder.bind(getItem(position))
    41.     }
    42. }
    • 在View中使用 ```kotlin // 大括号为item点击事件 private val locationAdapter = LocationAdapter {
      1.   binding.loginBox.spinner.setText(it.name_en)
      2.   binding.loginBox.locationRecyclerview.isVisible = false
      3.   locationId = it.location_id
      }

    locationRecyclerview.apply { layoutManager = GridLayoutManager(requireContext(), 1) adapter = locationAdapter } locationAdapter.submitList(data) // 提交数据 locationAdapter.submitList(data){ // 数据填充完成后的回调 参数多选

    } ```