如何更改 findViewById 以查看绑定？

Posted 2023-04-19

【中文标题】如何更改 findViewById 以查看绑定？

【英文标题】：How can i change findViewById to view binding?

【发布时间】：2021-08-14 20:16:29

【问题描述】：

这是我的适配器代码；

    class ModelViewHolder(view: View) : RecyclerView.ViewHolder(view) 
    private val chName: TextView = view.findViewById(R.id.chName)
    private val chBirthYear: TextView = view.findViewById(R.id.chBirthYear)
    private val chHeight: TextView = view.findViewById(R.id.chHeight)
    private val chHomeWorld: TextView = view.findViewById(R.id.chHomeWorld)

【问题讨论】：

你能发布你的完整适配器代码吗？

【参考方案1】：

获取列表项视图绑定类并如下更改：

//ItemModelBinding is the generated binding class for the list view item
class ModelViewHolder(val binding: ItemModelBinding) : RecyclerView.ViewHolder(binding.root) 

        fun bind(item: SomeModelClass) 
            binding.chName = item.chName
            binding.chBirthYear = item.chBirthYear
            binding.chHeight = item.chHeight
            binding.chHomeWorld= item.chHomeWorld
            
            binding.executePendingBindings()
        

override fun onBindViewHolder(holder: ModelViewHolder, position: Int) 
        val item = getItem(position)
        holder.bind(item)
    

【参考方案2】：

class ModelViewHolder(view: View) RecyclerView.ViewHolder(view)
    val binding = LayoutYouWantToUseBinding.bind(view)

【讨论】：

ViewHolder 必须是 ViewHolder 的子类。你会将什么视图传递给这个构造函数？

希望提供更多解释，但问题是“这是我的代码，我怎样才能将其更改为查看绑定”我认为这只是随机噪音，因为我认为我的答案中的代码几乎就是这个问题的答案。

【参考方案3】：

ListAdapter 是 RecyclerView.Adapter 基类，用于在 RecyclerView 中呈现 List 数据，包括在 后台线程上计算 List 之间的差异。

DiffUtil 有助于计算后台线程上两个列表之间的差异。并且仅更新已更改数据的视图意味着更少的 onBindViewHolder() 调用次数，如果我们仍然坚持使用 notifyDataSetChanged()，这将调用所有项目任何数据更改。

class ModelAdapter : ListAdapter<Model, ModelAdapter.ModelViewHolder>(ModelDiffCallBack()) 

    class ModelViewHolder(private val binding: ModelItemLayoutBinding) :
    RecyclerView.ViewHolder(binding.root) 

    fun bind(model: Model) 
        //if data binding is also enabled
        binding.model = model
        //else set data for each view one after another
        binding.txtTitle.text = model.title
        //and so on for all the items
        
        
        binding.executePendingBindings()
    

    companion object 
        fun from(parent: ViewGroup): ModelViewHolder 
            val layoutInflater = LayoutInflater.from(parent.context)
            val binding = ModelItemLayoutBinding.inflate(layoutInflater, parent, false)
            return ModelViewHolder(binding)
        
    


override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ModelViewHolder =
    ModelViewHolder.from(parent)

override fun onBindViewHolder(holder: ModelViewHolder, position: Int) 
    val model = getItem(position)
    holder.bind(model)


class ModelDiffCallBack : DiffUtil.ItemCallback<Model>() 
    override fun areItemsTheSame(oldItem: Model, newItem: Model): Boolean =
        oldItem === newItem

    override fun areContentsTheSame(oldItem: Model, newItem: Model): Boolean =
        oldItem == newItem