如何使用 Groupie RecyclerView 库和 Kotlin 删除项目时通知和更新列表

Question

我有一个用 Groupie 库实现的 RecyclerView，我可以很好地从列表中删除一个项目，但是需要更新视图才能看到更改。我想要类似 notifyDataSetChanged() 的东西，所以列表会立即更新。虽然我在这个阶段有点困惑，但尝试了几种不同的方法从 class 获取一个接口，该接口承载我的视图持有者，以便从持有适配器的片段中触发，但我想我现在被卡住了如果我能得到一些帮助的话。

class RecyclerProductItem(
private val activity: MainActivity,
private val product: Product, private val adapterListener: AdapterListener
) : Item<GroupieViewHolder>() {

companion object {
    var clickListener: AdapterListener? = null
}

override fun bind(viewHolder: GroupieViewHolder, position: Int) {

    viewHolder.apply {

        with(viewHolder.itemView) {

            clickListener = adapterListener

            ivTrash.setOnClickListener(object : View.OnClickListener {
                override fun onClick(v: View?) {
                    if (clickListener != null) {
                        Toast.makeText(context, "delete method to be added here", Toast.LENGTH_SHORT).show()
                        clickListener?.onClickItem(position)
                    } 
                }
            })

        }

    }
}

override fun getLayout() = R.layout.recyclerview_item_row

interface AdapterListener {
    fun onClickItem(position: Int)
}

}

这是我的片段。我尝试向适配器添加一个部分以查看它是否允许我为其检索侦听器，但是由于我的侦听器应该在布局中的特定项目下触发，这可能不是最佳解决方案，尽管不能使这项工作。

class ProductsListFragment : Fragment(), RecyclerProductItem.AdapterListener {

private lateinit var adapter: GroupAdapter<GroupieViewHolder>
private val section = Section()

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    return inflater.inflate(R.layout.fragment_products_list, container, false)
}

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)

    val linearLayoutManager = LinearLayoutManager(activity)
    recyclerView.layoutManager = linearLayoutManager

    adapter = GroupAdapter()

    adapter.add(section)


    recyclerView.adapter = adapter

    loadProducts()

}


private fun loadProducts() {

    GetProductsAPI.postData(object : GetProductsAPI.ThisCallback {

        override fun onSuccess(productList: List<JsonObject>) {

            for (jo in productList) {

                val gson = GsonBuilder().setPrettyPrinting().create()
                val product: Product =
                    gson.fromJson(jo, Product::class.java)

                adapter.add(
                    RecyclerProductItem(
                        activity as MainActivity,
                        Product(
                            product.id,
                            product.title,
                            product.description,
                            product.price
                        ),adapterListenerToBePassedHere 
                    )
                ) // This part is where I should be giving the listener, but get a red line since not sure how to get it to include it here.

            }

        }

    })

}


companion object {
    fun newInstance(): ProductsListFragment {
        return ProductsListFragment()
    }
}


override fun onClickItem(position: Int) {
    
    adapter.notifyItemRemoved(position)
}

}

非常感谢。

Answer 1

我认为您从追星族自述文件中遗漏了这个概念：

Modifying the contents of the GroupAdapter in any way automatically sends change notifications. Adding an item calls notifyItemAdded(); adding a group calls notifyItemRangeAdded(), etc.

所以要删除一个项目，请调用 section.remove(item)。但是，在您的 onClickItem 函数中，您目前仅传递位置。改为传递 clickListener?.onClickItem(this@RecyclerProductItem) 之类的项目。更理想和安全的是，您应该按 product.id 删除，例如clickListener?.onClickItem(this@RecyclerProductItem.product.id) 然后在 onClickItem() 中您只需搜索具有该产品 ID 的项目并将其删除。如果我不清楚，请告诉我。

Answer 2

根据@carson 的回复，这对我有用。必须将项目添加到部分，将部分添加到适配器，然后在单击该侦听器后根据适配器位置从部分中删除项目，将实现侦听器的方法作为参数之一传递以完成 GroupAdapter。

class RecyclerProductItem(
private val activity: MainActivity,
private val product: Product, private val adapterListener: AdapterListener
) : Item<GroupieViewHolder>() {

companion object {
    var clickListener: AdapterListener? = null
}

override fun bind(viewHolder: GroupieViewHolder, position: Int) {

    viewHolder.apply {

        with(viewHolder.itemView) {

            tvTitle.text = product.title

            clickListener = adapterListener

            ivTrash.setOnClickListener(object : View.OnClickListener {
                override fun onClick(v: View?) {
                    if (clickListener != null) {
                        Toast.makeText(context, "delete method to be added here", Toast.LENGTH_SHORT).show()
                        clickListener?.onClickItem(this@RecyclerProductItem.product.id, adapterPosition)
                    }
                }
            })

        }

    }
}

override fun getLayout() = R.layout.recyclerview_item_row

interface AdapterListener {
    fun onClickItem(id: Int, position: Int)
}

}

和

private fun loadProducts() {

    GetProductsAPI.postData(object : GetProductsAPI.ThisCallback,
        RecyclerProductItem.AdapterListener {

        override fun onSuccess(productList: List<JsonObject>) {

            Log.i(LOG_TAG, "onSuccess $LOG_TAG")

            for (jo in productList) {

                val gson = GsonBuilder().setPrettyPrinting().create()
                val product: Product =
                    gson.fromJson(jo, Product::class.java)

                val linearLayoutManager = LinearLayoutManager(activity)
                recyclerView.layoutManager = linearLayoutManager

                adapter = GroupAdapter()
                section.add(
                    RecyclerProductItem(
                        activity as MainActivity,
                        Product(
                            product.id,
                            product.title,
                            product.description,
                            product.price
                        ), this
                    )
                ) 

                adapter.add(section)
                recyclerView.adapter = adapter
            }

        }

        override fun onFailure() {
            Log.e(LOG_TAG, "onFailure $LOG_TAG")
        }

        override fun onError() {
            Log.e(LOG_TAG, "onError $LOG_TAG")
        }

        override fun onClickItem(id: Int, position: Int) {
            section.remove(adapter.getItem(position))
        }

    })

}

如何使用 Groupie RecyclerView 库和 Kotlin 删除项目时通知和更新列表

How to notify and update list when item has been deleted using Groupie RecyclerView library and Kotlin

java

android

android-adapter

kotlin

android-recyclerview