Java 如何在RecyclerView元素中单击时更改标题背景色？

我有一个

RecyclerView

和两个

ViewHolder

。一个用于标题，一个用于实际项目。现在，我想根据单击的列表项更改标题中的背景颜色（它是一个

ImageView

）。我试过这个，但得到：

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setBackgroundColor(int)' on a null object reference

这是我的代码：

case class MyItemHolder(view: View, items: Array[Entry]) extends RecyclerView.ViewHolder(view) with MyHolder with View.OnClickListener{
    view.setOnClickListener(this)
    lazy val currentItem = items(getAdapterPosition - 1)
    val textView: TextView = view.findViewById(R.id.textView).asInstanceOf[TextView]
    val imageView: ImageView = view.findViewById(R.id.imageView).asInstanceOf[ImageView]
    def bind(e: Entry): Unit = textView.setText(e.name)

    override def onClick(view: View): Unit = {
      Toast.makeText(getApplicationContext, s"You clicked ${currentItem.name}!", Toast.LENGTH_SHORT).show()
      imageView.setBackgroundColor(Color.parseColor(currentItem.color)) // crashed with NPE
    }
  }

标题的

ImageView

实际上位于其自己的

ViewHolder

中：

case class MyHeaderHolder(view: View) extends RecyclerView.ViewHolder(view) with MyHolder {
    val imageView: ImageView = view.findViewById(R.id.imageView).asInstanceOf[ImageView]
    val image = ContextCompat.getDrawable(getApplicationContext, R.drawable.title)
    def bind(): Unit = imageView.setImageDrawable(image)
  }

---

如何从我的

MyItemHolder

访问它？

尝试从侦听器中访问imageview：

    override def onClick(view: View): Unit = {
            Toast.makeText(getApplicationContext, s"You clicked ${currentItem.name}!", Toast.LENGTH_SHORT).show()
            val imageView: ImageView = view.findViewById(R.id.imageView).asInstanceOf[ImageView]
            imageView.setBackgroundColor(Color.parseColor(currentItem.color)) // crashed with NPE
    }

---

谢谢，但它仍然抛出NPE。