NotifyItemRemoved()异常：RecyclerView点击箭头误删非目标列表元素

我有一个包含8个国家的列表，点击第一个项的箭头图标时，预期删除第二个国家（中国），但实际操作后被删除的却是第三个国家。

点击前的列表：

点击后的列表：

我的CountryAdapter代码如下：

class CountryAdapter(
    private val context: Context,
    private val activity: Activity,
    private val countries: MutableList<Countries>,
) :
    RecyclerView.Adapter<RecyclerView.ViewHolder>() {

    private var isPressed = false
    private var deletedList: HashMap<Int, Countries> = HashMap()

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        val viewHolder: CountryViewHolder
        val inflater = LayoutInflater.from(parent.context)
        val holderView = inflater.inflate(R.layout.country_item, parent, false)
        viewHolder = CountryViewHolder(holderView)
        viewHolder.countryName = holderView.findViewById(R.id.countryName)
        viewHolder.arrowImg = holderView.findViewById(R.id.arrow)
        return viewHolder
    }
    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        holder.setIsRecyclable(false)
        val viewHolder = holder as CountryViewHolder
        val txt = viewHolder.itemView.findViewById<TextView>(R.id.countryName)
        val baseLayout = viewHolder.itemView.findViewById<LinearLayout>(R.id.base_linear_layout)
        val basedecLayout = viewHolder.itemView.findViewById<LinearLayout>(R.id.base_des_layout)
        val arrow = viewHolder.itemView.findViewById<ImageView>(R.id.arrow)
        if (position != 0) {
            arrow.visibility = View.GONE
        } else {
            basedecLayout.setOnClickListener {
                arrow.performClick()
            }
            arrow.setOnClickListener {
                if (!isPressed) {
                    for (i in 1..1) {
                        deletedList[i] = countries[1]
                        countries.removeAt(1)   //Problem is here
                        notifyItemRemoved(1)    // problem is here
                    }
                }
//                else {
//                    for (i in 3 downTo 1) {
//                        countries.add(1, deletedList[i]!!)
//                        notifyItemInserted(1)
//                    }
//                    deletedList.clear()
//                }
                isPressed = !isPressed
            }
        }
        txt.text = countries[position].name
    }

    override fun getItemCount(): Int {
        return countries.size
    }

    class CountryViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        lateinit var countryName: TextView
        lateinit var arrowImg: ImageView
    }
}

问题原因 #

1. 点击事件重复绑定：在onBindViewHolder中每次绑定holder时都会给箭头添加新的点击监听器，加上你设置了holder.setIsRecyclable(false)禁用了ViewHolder复用，导致同一个holder会被多次绑定点击事件。点击一次箭头会触发多次删除逻辑：第一次删除索引1的项（中国），第二次删除此时新的索引1项（原列表的第三个国家），最终表现为删除了第三个国家。
2. 多余的循环逻辑：for (i in 1..1)完全是冗余代码，只会执行一次，却增加了代码复杂度。

修复方案 #

方案1：将点击事件绑定移至ViewHolder构造函数（推荐）

在ViewHolder初始化时就设置点击事件，避免重复绑定，同时通过回调处理删除逻辑：

class CountryAdapter(
    private val context: Context,
    private val activity: Activity,
    private val countries: MutableList<Countries>,
) :
    RecyclerView.Adapter<CountryAdapter.CountryViewHolder>() {

    private var isPressed = false
    private var deletedList: HashMap<Int, Countries> = HashMap()

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CountryViewHolder {
        val inflater = LayoutInflater.from(parent.context)
        val holderView = inflater.inflate(R.layout.country_item, parent, false)
        return CountryViewHolder(holderView) {
            if (!isPressed) {
                // 保存要删除的项
                deletedList[1] = countries[1]
                // 删除索引1的项
                countries.removeAt(1)
                notifyItemRemoved(1)
                // 通知后续项位置变化，避免显示异常
                notifyItemRangeChanged(1, countries.size - 1)
            }
            isPressed = !isPressed
        }
    }

    override fun onBindViewHolder(holder: CountryViewHolder, position: Int) {
        // 移除不必要的禁用复用逻辑，提升性能
        holder.countryName.text = countries[position].name
        holder.arrowImg.visibility = if (position == 0) View.VISIBLE else View.GONE
    }

    override fun getItemCount(): Int {
        return countries.size
    }

    class CountryViewHolder(
        itemView: View,
        private val onArrowClick: () -> Unit
    ) : RecyclerView.ViewHolder(itemView) {
        val countryName: TextView = itemView.findViewById(R.id.countryName)
        val arrowImg: ImageView = itemView.findViewById(R.id.arrow)
        private val basedecLayout: LinearLayout = itemView.findViewById(R.id.base_des_layout)

        init {
            // 在ViewHolder初始化时绑定点击事件，仅执行一次
            arrowImg.setOnClickListener {
                onArrowClick()
            }
            basedecLayout.setOnClickListener {
                arrowImg.performClick()
            }
        }
    }
}

方案2：清空旧监听器后再绑定（临时修复）

如果不想修改ViewHolder结构，可以在设置新的点击监听器前先移除旧的，同时删除冗余循环：

// 在arrow.setOnClickListener前添加
arrow.setOnClickListener(null)
arrow.setOnClickListener {
    if (!isPressed) {
        deletedList[1] = countries[1]
        countries.removeAt(1)
        notifyItemRemoved(1)
        notifyItemRangeChanged(1, countries.size - 1)
    }
    isPressed = !isPressed
}

额外优化建议 #

• 尽量不要禁用ViewHolder复用（setIsRecyclable(false)），这会大幅降低RecyclerView的滚动性能，仅在特殊场景下使用。
• 可以将deletedList改为MutableList<Countries>，比HashMap更适合存储被删除的列表项。

内容的提问来源于stack exchange，提问作者Sunny