Question

这是我第一次遇到此问题，它与ArrayList，List或任何种类的集合无关-与Int有关。

我正在使用Kotlin和Moxy的Presenter初始化适配器。这是我初始化的方式：

adapter = WeeksAdapter(context, weeks, chosenWeekPosition, this)

这是我的WeeksAdapter部分：

    class WeeksAdapter (private val context: Context, private val weeks: ArrayList<WeekChoice>, var chosenPosition: Int, private val listener: OnCurrentWeekChangedListener):
        RecyclerView.Adapter<WeeksAdapter.ViewHolder>() {
        override fun onBindViewHolder(holder: ViewHolder, position: Int) {
            val week = weeks[position]
            holder.tv.background = context.resources.getDrawable(
                if (position == chosenPosition) R.drawable.week_circle_background_active else  R.drawable.week_circle_background_inactive , null)
            holder.tv.setTextColor( context.resources.getColor ( if (position == chosenPosition) android.R.color.white else  R.color.textColor ))
            holder.tv.text = "${week.numberOfWeek}"
            holder.tv.setOnClickListener {
                listener.onWeekClick(position)
            }
        }
}

因此，当我在演示者中更改selectedPosition字段并调用adapter?.notifyDataSetChanged()时-selectedPosition不会在适配器中更改或更新-我在调试中检查了它-不会更改。

请问我该如何解决

Answer 1

我不熟悉此演示者，但您的selectedPosition不变。创建适配器后，它不会更改。您需要对其进行更新的功能

class WeeksAdapter (private val context: Context, private val weeks: ArrayList<WeekChoice>, var chosenPosition: Int, private val listener: OnCurrentWeekChangedListener):
        RecyclerView.Adapter<WeeksAdapter.ViewHolder>() {


    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val week = weeks[position]
        holder.tv.background = context.resources.getDrawable(
                if (position == chosenPosition) R.drawable.week_circle_background_active else  R.drawable.week_circle_background_inactive , null)
        holder.tv.setTextColor( context.resources.getColor ( if (position == chosenPosition) android.R.color.white else  R.color.textColor ))
        holder.tv.text = "${week.numberOfWeek}"
        holder.tv.setOnClickListener {
            listener.onWeekClick(position)
        }
    }

    fun updatePosition(newPosition: Int) {
        chosenPosition = newPosition
    }
}

通过此函数更新位置，然后调用适配器？.notifyDataSetChanged（）

Answer 2

从UI线程中调用notifyDataSetChanged（）。

RecyclerView适配器不会在notifyDataSetChanged（）（不是Collection）上更新

2 个答案: