/**

• 显示播放列表
  */
  private fun showPlayList() {
  val list = iService?.getPlayList()
  list?.let {
  //创建adapter

  val adapter = PopAdapter(list)
  //获取底部高度
  val bottomH = audio_player_bottom.height
  val popWindow = PlayListPopWindow(this, adapter,this,window)
  popWindow.showAsDropDown(audio_player_bottom,0,-bottomH)
  

  }
  }
  example:
  class PlayListPopWindow(context: Context, adapter: BaseAdapter, listener: AdapterView.OnItemClickListener, val window: Window) : PopupWindow() {
  //记录当前应用程序窗体透明度
  var alpha: Float = 0f

  init {

  //记录当前窗体的透明度
  alpha = window.attributes.alpha
  //设置布局
  val view = LayoutInflater.from(context).inflate(R.layout.pop_playlist, null, false)
  //获取listview
  val listView = view.find<ListView>(R.id.listView)
  //适配
  listView.adapter = adapter
  //设置列表条目点击事件
  listView.setOnItemClickListener(listener)
  contentView = view
  //设置宽度和高度
  width = ViewGroup.LayoutParams.MATCH_PARENT
  //设置高度为屏幕高度3/5
  val manager = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
  val point = Point()
  manager.defaultDisplay.getSize(point)
  val windowH = point.y
  height = (windowH * 3) / 5
  //设置获取焦点
  isFocusable = true
  //设置外部点击
  isOutsideTouchable = true
  //能够响应返回按钮(低版本popwindow点击返回按钮能够dismiss关键)
  setBackgroundDrawable(ColorDrawable())
  //处理popwindow动画
  animationStyle = R.style.pop
  

  }

  override fun showAsDropDown(anchor: View?, xoff: Int, yoff: Int, gravity: Int) {

  super.showAsDropDown(anchor, xoff, yoff, gravity)
  //popwindow已经显示
  val attributes = window.attributes
  attributes.alpha = 0.3f
  //设置到应用程序窗体上
  window.attributes = attributes
  

  }

  override fun dismiss() {

  super.dismiss()
  //popwindows隐藏 恢复应用程序窗体透明度
  val attributes = window.attributes
  attributes.alpha = alpha
  window.attributes = attributes
  

  }
  }