Get all available presets from Equalizer class

GetAllPresets.kt

private val presetList = ArrayList<Preset>(0)
private var presetAdapter: PresetAdapter? = null

private fun setupPresetList() {
  
  presetAdapter = PresetAdapter(this) { position: Int, preset: Preset ->
    setSelectedPreset(position, preset)
  }
  presetAdapter?.enabled = eqEnabled
  presetAdapter?.currentPreset = eqPreset

  list_preset.layoutManager = LinearLayoutManager(this)
  list_preset.isNestedScrollingEnabled = true
  list_preset.adapter = presetAdapter

  presetList.clear()
  val presets = equalizer?.numberOfPresets
  // Get preset names
  (0 until presets!!)
          .map { equalizer?.getPresetName(it.toShort()) }
          .mapTo(presetList) { Preset(it) }
          .run {
              presetAdapter?.notifyDataSetChanged()
          }
}

private fun setSelectedPreset(position: Int, preset: Preset) {
  var currentEqPreset = equalizer?.getCurrentPreset()

  if(currentEqPreset !== preset.name) {
      val presets = equalizer?.numberOfPresets
      // To set the preset in Equalizer class
      equalizer?.usePreset(position.toShort())
    
      // Get the band level values of the preset, then display to UI
      val numberOfBands = equalizer?.numberOfBands
      val lowestBandLevel = equalizer?.bandLevelRange?.get(0)
      (0 until numberOfBands!!)
              .forEach {
                  val band = it
                  val level = equalizer?.getBandLevel(it.toShort())?.minus(lowestBandLevel!!)
                  view_eq.setBandLevel(band, level!!)
              }
  }
}