Android仿微信朋友圈点击评论自动定位到相关行功能

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data class TopClass(val value: String)

class MainAdapter(private val beans: ArrayList, val context: Context) : RecyclerView.Adapter() {
  var height = 0
  enum class TYPE(val value: Int) {
    TOP(0), NORMAL(1)
  }
  override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): RecyclerView.ViewHolder {
    when(viewType) {
      TYPE.NORMAL.value -> {
        val view = LayoutInflater.from(context).inflate(R.layout.adapter_main, parent, false)
        return MainNormalViewHolder(view)
      }
      TYPE.TOP.value -> {
        val view = LayoutInflater.from(context).inflate(R.layout.adapter_top, parent, false)
        return MainTopViewHolder(view)
      }
    }
    throw Exception()
  }
  override fun getItemCount() = beans.size
  override fun onBindViewHolder(holder: RecyclerView.ViewHolder?, position: Int) {
    if (holder != null) {
      when(getItemViewType(position)) {
        TYPE.NORMAL.value -> {
          (holder as MainNormalViewHolder).setText(beans[position] as String)
          holder.clickComment(holder.layoutPosition)
        }
        TYPE.TOP.value -> {}
      }
    }
  }
  override fun getItemViewType(position: Int): Int {
    when(beans[position]) {
      is String -> return TYPE.NORMAL.value
      is TopClass -> return TYPE.TOP.value
    }
    return super.getItemViewType(position)
  }
  inner class MainNormalViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
    fun setText(text: String) {
      itemView.tv_title.text = text
    }
    fun clickComment(position: Int) {
      itemView.tv_comment.setOnClickListener {
        (context as MainActivity).showInputComment(itemView.tv_comment, position)
      }
    }
  }
  inner class MainTopViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView)
}

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fun showInputComment(commentView: View, position: Int) {
  // RV中评论区起始Y的位置
  val rvInputY = getY(commentView)
  val rvInputHeight = commentView.height
  dialog = Dialog(this, android.R.style.Theme_Translucent_NoTitleBar)
  dialog!!.setContentView(R.layout.dialog_comment)
  dialog!!.show()
  val handler = object : Handler() {}
  handler.postDelayed({
    // 对话框中的输入框Y的位置
    val dialogY = getY(dialog!!.findViewById(R.id.dialog_layout_comment))
    rv_main.smoothScrollBy(0, rvInputY - (dialogY - rvInputHeight))
  }, 300)
}
private fun getY(view: View): Int {
  val rect = IntArray(2)
  view.getLocationOnScreen(rect)
  return rect[1]
}

handler.postDelayed({
  // 对话框中的输入框Y的位置
  val dialogY = getY(dialog!!.findViewById(R.id.dialog_layout_comment))
  if (position == arrays.size - 1) {
    arrays.add(BottomClass(""))
    adapter?.height = dialog!!.findViewById(R.id.dialog_layout_comment).height
    adapter?.notifyDataSetChanged()
  }
  rv_main.smoothScrollBy(0, rvInputY - (dialogY - rvInputHeight))
}, 300)

window.decorView.viewTreeObserver.addOnGlobalLayoutListener {
  val rect = Rect()
  window.decorView.getWindowVisibleDisplayFrame(rect)
  val displayHeight = rect.bottom - rect.top
  val height = window.decorView.height
  val keyboardHeight = height - displayHeight
  if (previousKeyboardHeight != keyboardHeight) {
    val hide = displayHeight.toDouble() / height > 0.8
    if (hide) {
      if (arrays[arrays.size - 1] is BottomClass) {
        arrays.removeAt(arrays.size - 1)
        adapter?.notifyDataSetChanged()
      }
      dialog?.dismiss()
    }
  }
}