瀑布流布局是一種新的佈局方式，項目可以自動匹配大小適應螢幕。

在RecycleView中，要呈現瀑布流樣式，需要用到StaggeredGridLayoutManager來實作。

先上Acitvity

class StaggeredGridViewActivity : AppCompatActivity() {
    lateinit var staggeredGridLayoutManager: StaggeredGridLayoutManager
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        title="StaggeredGridLayout"
        staggeredGridLayoutManager = StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL)
        recycleview_main.layoutManager= staggeredGridLayoutManager
        val adapter = RVStaggeredGridViewAdapter(this, SwitchData.defaultList)
        recycleview_main.adapter = adapter
    }
}

StaggeredGridLayoutManager其實跟之前的GridLayoutManager的用法一樣，要宣告spanCount以及方向。
所以對GridLayoutManager熟悉的朋友們在使用StaggeredGridLayoutManager應該沒有困難。

StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL)

Adapter

class RVStaggeredGridViewAdapter(
    private val context: Context,
    private val dataList: MutableList<SwitchData>
) :
    RecyclerView.Adapter<RVStaggeredGridViewAdapter.ViewHolder>() {
    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}")
        }
    }
}

瀑布流的顯示，其實在google的圖片搜尋就是一個最好的例子。
在一些網路型錄中顯示商品時也是常見的顯示方式。
除了有效運用剩餘空間的優點之外，在視覺上也是一種整齊美觀的享受。