在片段中调用方法

Question

我有一个类，当按钮被点击时播放声音。我需要在onPause方法中停止播放声音，但我不知道如何在片段中调用类的停止函数。

在适配器中我调用Music(values).playButton()在片段中，我想调用Music().stop()来停止声音，但是该类需要的参数不在片段

中。我如何在片段中调用这个方法?

类音乐

class Music(var button: Button, val context: Context, val resources: Resources, val Id: Int, var buttonArray: MutableList<Button>, val mpArray: MutableList<MediaPlayer>) {
fun play() : MediaPlayer {
if (buttonArray.size >= 2) {
buttonArray.removeFirst()
}
if (mpArray.size >= 2) {
mpArray.removeFirst()
}
mpArray.add(MediaPlayer.create(context, Id))
buttonArray.add(button)
if (mpArray.size == 1 && !mpArray[0].isPlaying) {
mpArray[0].start()
return mpArray[0]
} else if (mpArray.size == 2 && buttonArray[0] == buttonArray[1]) {
if (mpArray[0].isPlaying) {
mpArray[0].pause()
mpArray[0].reset()
mpArray[0].release()
} else if (!mpArray[1].isPlaying) {
mpArray[1].start()
return mpArray[1]
}
}
if (mpArray.size == 2 && buttonArray[0] != buttonArray[1]) {
if (mpArray[0].isPlaying) {
mpArray[0].pause()
mpArray[0].reset()
mpArray[0].release()
mpArray[1].start()
} else if (!mpArray[0].isPlaying) {
mpArray[1].start()
return mpArray[1]
}
}
return MediaPlayer.create(context, Id)
}
fun stop() {
if (play().isPlaying) {
play().stop()
play().release()
}
}

<<p>适配器/strong>

class Adapters(private val cards: List<Card>, val resources: Resources, val context: Context, private val musicPlayerListener: MusicPlayerListener) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
private var buttonArray = mutableListOf<Button>()
private var mpArray = mutableListOf<MediaPlayer>()
private lateinit var music: Music
fun playMusic() {
musicPlayerListener.onMusicPlay(music.play())
}
override fun getItemViewType(position: Int): Int = when(cards[position]) {
is Card.AudioButton -> 11
else -> throw IllegalArgumentException("Error")
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
return object : RecyclerView.ViewHolder(
when(viewType) {
11 -> LayoutInflater.from(parent.context).inflate(R.layout.in_lesson_audio_button, parent, false)
else -> throw IllegalArgumentException("Error")
}) {
}
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
when(val card = cards[position]) {
is Card.AudioButton -> {
val button = holder.itemView.findViewById<Button>(R.id.in_lesson_audio_button)
button.setOnClickListener {
Music(button, context, resources, getAudioId(card.audioButton), buttonArray, mpArray).play()
}
}
}
}
override fun getItemCount() = cards.size
private fun getAudioId(audioElement: String): Int = resources.getIdentifier(audioElement, "raw", context.packageName)

}

class Fragment : Fragment(), MusicPlayerListener  {
private val args: DetailsFragmentArgs by navArgs()
var mMediaPlayer: MediaPlayer? = null

override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?,
): View? {
val binding = inflater.inflate(R.layout.fragment, container, false)
val recyclerView = binding.findViewById<RecyclerView>(R.id.list_view)
recyclerView.layoutManager = LinearLayoutManager(context)
recyclerView.adapter = Adapters(parseLesson(resources,R.xml.text), resources, requireContext() )
return binding
}
override fun onPause() {
super.onPause()
mMediaPlayer?.stop()
}
override fun onMusicPlay(mediaPlayer: MediaPlayer) {
mMediaPlayer = mediaPlayer
}

}

Answer 1

当你调用Music.play()时，它将返回一个MediaPlayer的实例，你应该将其发送回fragment并将其作为局部变量保存在fragment中。然后从片段中，使用MediaPlayer的实例来调用stop()。

class ExampleAdapter(private val musicPlayerListener: MusicPlayerListener) {
private lateinit var music: Music
fun playMusic() {
musicPlayerListener.onMusicPlay(music.play())
}
}
class ExampleFragment : MusicPlayerListener {
var mMediaPlayer: MediaPlayer? = null

override fun onMusicPlay(mediaPlayer: MediaPlayer) {
mMediaPlayer = mediaPlayer
}
override fun onPause() {
super.onPause()
mMediaPlayer?.stop()
}
}
interface MusicPlayerListener {
fun onMusicPlay(mediaPlayer: MediaPlayer)
}