在RecyclerView适配器中使用正确的上下文

Question

在context适配器中使用SharedPreference时应使用哪个RecyclerView？这是令人困惑的，因为在默认设置中，context中的val mSharedPreferences = PreferenceManager.getDefaultSharedPreferences(context)显示为未解析的引用。

class MyRVAdapter(private val myString: ArrayList<String>): RecyclerView.Adapter<MyRVAdapter.MyViewHolder>() {
    private val typeA = 1
    private val typeB = 2

    override fun onCreateViewHolder(parent: ViewGroup, type: Int): MyViewHolder {
        return when (type) {
            typeA -> MyViewHolder(inflateHelper(R.layout.rv_type_a, parent))
            typeB -> MyViewHolder(inflateHelper(R.layout.rv_type_b, parent))
            else -> MyViewHolder(inflateHelper(R.layout.rv_type_a, parent))
        }
    }

    override fun onBindViewHolder(viewHolder: MyViewHolder, position: Int) {
        if (getItemViewType(position) == typeA) {
            // Check preference (what's the correct context?)
            val mSharedPreferences = PreferenceManager.getDefaultSharedPreferences(context)
            valueDestinationExpanded = mSharedPreferences.getBoolean("my_preference", true)
        }
        else if (getItemViewType(position) == typeB) {
        }
    }

    private fun inflateHelper(resId: Int, parent: ViewGroup): View {
        return LayoutInflater.from(parent.context).inflate(resId, parent, false)
    }

    override fun getItemViewType(position: Int): Int {
        return if (position == 0) typeA
        else typeB
    }
}

Answer 1

任何Context都可以。无法解析您的context引用，因为您没有该名称的变量或属性，就像在View或Activity中一样。在onBindViewHolder中获得一个最方便的方法是viewHolder.itemView.context（或Java中的viewHolder.itemView.getContext()）。