在Kotlin中，访问RecyclerView适配器的内部类中的外部类成员的最佳方法是什么？

Question

I'm creating my first Kotlin classes in my Android application. Usually, for logging purposes, I have a constant with the name TAG. I defined it in my RecyclerView Adapter as:

class MyAdapter(private val dataList: ArrayList<MyData>): RecyclerView.Adapter<MyAdapter.ViewHolder>() {

    private val TAG: String? = MyAdapter::class.simpleName
    .
    .
    .

    class ViewHolder(v: View) : RecyclerView.ViewHolder(v), View.OnClickListener {
        fun bindData(){
            //some statements
        }

        override fun onClick(p0: View?) {
           //I want to use the above defined TAG here as I would do in Java:
           // Log.d(TAG, "");
        }
    }
}

I am unable to access the variable TAG in the onClick()

Answer 1

您可以将ViewHolder类设置为inner

Answer 2

Use the companion object :

class MyAdapter(private val dataList: ArrayList<String>) :
    RecyclerView.Adapter<MyAdapter.ViewHolder>() {

    class ViewHolder(v: View) : RecyclerView.ViewHolder(v), View.OnClickListener {
        fun bindData() {
            //some statements
        }

        override fun onClick(p0: View?) {
            Log.d(TAG, "")
        }
    }

    companion object {
        val TAG: String? = MyAdapter::class.simpleName
    }

}

Answer 3

You can also put

private val TAG: String? = MyAdapter::class.simpleName

on top level of the file.