Android自定義PopWindow

我實現的效果是點擊按鈕 一個從底部出現popwindow的動畫 窗體顏色變灰 顯示recyclerview列表，以及實現類傳入適配器數據和點擊事件 以及點擊外部隱藏popwindow

上代碼：

class PlayListPopWindow(context: Context, adapter: PopWindowAdapter,listener:BaseQuickAdapter.OnItemClickListener,val window: Window):PopupWindow() {
    var alpha:Float = 0f

    init {
        //記錄當前透明度
        alpha =  window.attributes.alpha
        //設置佈局
         val  view =    LayoutInflater.from(context).inflate(R.layout.pop_playlist,null,false)
        //獲取recyclerview
        val recyclerview = view.findViewById<RecyclerView>(R.id.pop_recy)
            //適配
        recyclerview.layoutManager = LinearLayoutManager(context)
        recyclerview.adapter= adapter
       adapter.setOnItemClickListener(listener)
        contentView = view
        //設置寬高
        width = ViewGroup.LayoutParams.MATCH_PARENT
        //設置高度爲屏幕的3/5
        val manager =context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
        val point = Point()
        manager.defaultDisplay.getSize(point)
        val windowheight = point.y
        height = (windowheight*3)/5
        //設置獲取焦點
        isFocusable = true
         //點擊外部空白區域
        isOutsideTouchable = true
        //能夠響應返回按鈕    低版本點擊返回按鈕能dismiss
        setBackgroundDrawable(ColorDrawable())

        //處理popwindow動畫
        animationStyle = R.style.pop
    }

    override fun showAsDropDown(anchor: View?, xoff: Int, yoff: Int, gravity: Int) {
        super.showAsDropDown(anchor, xoff, yoff, gravity)
        //當前popwindow已經顯示了
        val attarbutes = window.attributes
        attarbutes.alpha = 0.3f
        //設置到應用程序窗體上面
        window.attributes = attarbutes
    }

    override fun dismiss() {
        super.dismiss()
        //隱藏
        val attarbutes = window.attributes
        attarbutes.alpha = alpha
        window.attributes  = attarbutes
    }
}

實現類

 //點擊事件
override fun onItemClick(adapter: BaseQuickAdapter<*, *>?, view: View?, position: Int) {
        //播放當前歌曲
        Iservice?.playPosition(position)
    }

 //初始化數據
 list?.let {
            val adapter = PopWindowAdapter(it)
            //獲取底部高度
            val bottomH = woshibottom.height
            val popWindow = PlayListPopWindow(this,adapter,this,window)

            popWindow.showAsDropDown(woshibottom,0,bottomH)
        }