SortedListAdapterCallback之RecycleView数据刷新

RecycleView 列表动态刷新，页面不动，只刷新某个符合条件的item

有人用过 DiffUtil ，也可以，不过发现了SortedList 更好。写了一个测试

• SortedList是一个有序列表（数据集）的实现，可以保持ItemData都是有序的，并(自动)通知列表(RecyclerView)（数据集）中的更改。

data class TestListBean(
    var index:Int,
    var tag:String,
)

自定义一个SortedList

class SortListCallBack(adapter: TestSortedAdapter?):SortedListAdapterCallback(adapter) {

    
    override fun compare(o1: TestListBean?, o2: TestListBean?): Int {
        o1 ?: return -1
        o2 ?: return -2
        return o1.index - o2.index
    }

    override fun areContentsTheSame(oldItem: TestListBean?, newItem: TestListBean?): Boolean {
        if (oldItem?.index != newItem?.index){
            return false
        }
        if (oldItem?.tag != newItem?.tag){
            return false
        }
        return true
    }

    override fun areItemsTheSame(item1: TestListBean?, item2: TestListBean?): Boolean {
        return item1?.index == item2?.index
    }

    override fun getChangePayload(item1: TestListBean?, item2: TestListBean?): Any? {
        return super.getChangePayload(item1, item2)
    }
}

适配器

class TestSortedAdapter:BaseQuickAdapter(R.layout.item_test_sort_layout) {

    val mCallback =SortListCallBack(this)
    val mSortedList = SortedList(TestListBean::class.java,SortedList.BatchedCallback(mCallback))

    override fun onItemViewHolderCreated(viewHolder: BaseViewHolder, viewType: Int) {
        super.onItemViewHolderCreated(viewHolder, viewType)
        ItemTestSortLayoutBinding.bind(viewHolder.itemView)
    }

    override fun convert(holder: BaseViewHolder, item: TestListBean) {
        holder.getBinding()?.run {
            tvTagName.text = item.tag
        }

    }

    fun setSortedList(list: MutableList){
        data.addAll(list)
        mSortedList.addAll(list)
    }

    fun sorted():SortedList{
        return mSortedList
    }
}

Activity

class MainActivity : AppCompatActivity() {

    private lateinit var binding:ActivityMainBinding
    private val viewModel by viewModels()
    private var adapter:TestSortedAdapter? = null

    @SuppressLint("NotifyDataSetChanged")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        viewModel.listData.observe(this){
            adapter?.setSortedList(it)
        }

        if (adapter == null){
            adapter = TestSortedAdapter()
        }

        binding.recycleView.adapter = adapter

        viewModel.initList()

        binding.btnChange.setOnClickListener {
            val index = (0..20).random()
            WLog.e("btnChange","=====> 更新下标：$index")
            val list = mutableListOf()
            adapter?.data?.let { it1 -> list.addAll(it1) }
            val bean = list.find { it.index == index }
            bean?.tag = "更新：$index"
            adapter?.sorted()?.run {
                beginBatchedUpdates()
                clear()
                adapter?.notifyDataSetChanged()
                addAll(list)
                endBatchedUpdates()
            }
        }
    }
}

ListViewModel 只是一个初始化测试数据的。

初始化页面：

image.png

当前几右下按钮时，随时的下标数据开始更新，页面直接更新对应的item 不会发生移动

下图，更新后的页面：

AE639F217701A09A1D1DFE23BE5CF0B0.jpg

参考：IM会话列表刷新优化思考 https://juejin.cn/post/7183517773790707769