原先Android上是有GridView，以及GridLayout可以用。
但是因為效能問題已經被淡出我們常用的元件類別。
有時候我們還是需要顯示像是圖示等格狀排列，其實現在RecycleView上也可以實現這種樣式。

在RecycleView中，要呈現GridView的樣式，需要用到GridLayoutManager來實作。

一樣先上Activity

class GridViewActivity : AppCompatActivity() {
    lateinit var gridLayoutManager: GridLayoutManager
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        gridLayoutManager = GridLayoutManager(this,2)
        recycleview_main.layoutManager= gridLayoutManager //預設
        val adapter = RVGridViewAdapter(this, SwitchData.defaultList)
        recycleview_main.adapter = adapter
    }
}

在設定GridLayoutManager時，需要填入spanCount個數

gridLayoutManager = GridLayoutManager(this,2)

這邊填2表示我們要以每兩個項目作顯示。

Adapter

class RVGridViewAdapter(
    private val context: Context,
    private val dataList: MutableList<SwitchData>
) :
    RecyclerView.Adapter<RVGridViewAdapter.ViewHolder>() {
    lateinit var mContext: Context
    init {
        mContext = context
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        var view = LayoutInflater.from(parent.context).inflate(R.layout.recycleview_gridview_layout, parent, false)
        return ViewHolder(view, viewType)
    }

    override fun getItemCount(): Int {
        return dataList.size
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val item = dataList[position]
        holder?.bindModel(item)
    }

    inner class ViewHolder(itemView: View, var viewType: Int) : RecyclerView.ViewHolder(itemView) {
        var nameTextView: TextView? = null
        var likeTextView: TextView? = null
        var commentTextView: TextView? = null

        fun bindModel(item: SwitchData) {
            var imageView: ImageView? = null
            imageView = itemView.findViewById(R.id.iv_small)
            nameTextView = itemView.findViewById(R.id.tv_namesmall)

            Glide.with(mContext).load(item.image).into(imageView!!)
            nameTextView?.setText(item.name)
            likeTextView?.setText("Likes: ${item.like}")
            commentTextView?.setText("comments: ${item.comment}")
        }
    }
}

透過RecycleView套用GridLayoutManager，我們又能使用這類GridView顯示樣式
同時又能享用RecycleView的資源效能回收的機制。