java在适配器类中获取ArrayIndexOutOfBoundsException

Question

当我单击项目时，我得到

java.lang.ArrayIndexOutOfBoundsException: length = 10; index = -1

这是我的onCreateViewHolder方法，当我单击item时，我想打开DetailActivity并发送数据

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
    val view = LayoutInflater.from(parent.context).inflate(R.layout.alphabet_item, parent, false)
    val holder = ViewHolder(view)
    view.setOnClickListener {
        val intent = Intent(parent.context, ItemAlphabetDetailActivity::class.java)
        intent.putExtra("NAME", alphabets[holder.position].context)/*
        intent.putExtra("CONTEXT", alphabets[holder.adapterPosition].context)
        intent.putExtra("IMAGE", alphabets[holder.adapterPosition].image)
        intent.putExtra("SOUND", alphabets[holder.adapterPosition].sound)*/
        parent.context.startActivity(intent)
    }
    return ViewHolder(view)
}

这是我的班级ItemAlphabetAdapter

class ItemAlphabetAdapter(
private val alphabets: ArrayList<ItemAlphabet>
) : RecyclerView.Adapter<ItemAlphabetAdapter.ViewHolder>() {


override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
    val view = LayoutInflater.from(parent.context).inflate(R.layout.alphabet_item, parent, false)
    val holder = ViewHolder(view)
    view.setOnClickListener {
        val intent = Intent(parent.context, ItemAlphabetDetailActivity::class.java)
        intent.putExtra("NAME", alphabets[holder.position].context)/*
        intent.putExtra("CONTEXT", alphabets[holder.adapterPosition].context)
        intent.putExtra("IMAGE", alphabets[holder.adapterPosition].image)
        intent.putExtra("SOUND", alphabets[holder.adapterPosition].sound)*/
        parent.context.startActivity(intent)
    }
    return ViewHolder(view)
}

override fun getItemCount(): Int = alphabets.size


override fun onBindViewHolder(holder: ItemAlphabetAdapter.ViewHolder, position: Int) {

    val alphabet = alphabets[position]
    holder.name.text = alphabet.name
    holder.image.visibility = alphabet.image
}

class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
    val image: ImageView = itemView.findViewById(R.id.alphabet_image)
    val name: TextView = itemView.findViewById(R.id.alphabet_name)

}

}

Answer 1

您必须编写以下代码

val intent = Intent(parent.context, ItemAlphabetDetailActivity::class.java)
        intent.putExtra("NAME", alphabets[holder.position].context)/*
        intent.putExtra("CONTEXT", alphabets[holder.adapterPosition].context)
        intent.putExtra("IMAGE", alphabets[holder.adapterPosition].image)
        intent.putExtra("SOUND", alphabets[holder.adapterPosition].sound)*/
        parent.context.startActivity(intent)

在onBindViewHolder（）中，它已经将位置作为参数之一提供给您

Answer 2

onCreateViewHolder方法不是每次recyclerview需要显示一行时都被调用，而是仅当需要创建新视图且屏幕上没有足够的视图时才被调用。而是为每个位置调用onBindViewHolder方法。因此，要获得行的确切位置，请使用holder.adapterPosition

Answer 3

试试这个。在onBindViewHolder中移动setOnClickListener

项目视图。setOnClickListener{ 如果（位置！=-1）{

    val intentIntent(itemView.context,ItemAlphabetDetailActivity::class.java)
    intent.putExtra("NAME", alphabets[position].context)/*
    intent.putExtra("CONTEXT", alphabets[position].context)
    intent.putExtra("IMAGE", alphabets[position].image)
    intent.putExtra("SOUND", alphabets[position].sound)*/
    parent.context.startActivity(intent)
}}