尝试使用android studio在android中创建简单的音频播放器应用程序，但它无法正常工作。

时间：2015-07-08 05:39:55

标签： android android-studio android-mediaplayer

代码的主要部分：

        // This is event handler for buttonClick event
    void buttonClick(){

            if (buttonPlayStop.getText() ==                     getString(R.string.play_str)) {
                buttonPlayStop.setText(getString(R.string.pause_str));
                 try{
                    mediaPlayer.start();
                    startPlayProgressUpdater();
                }catch (IllegalStateException e) {
                   if(mediaPlayer.isPlaying()) {
                       mediaPlayer.pause();


                   }
                   mediaPlayer.pause();
                   mediaPlayer.seekTo(0);
                }
            }else {
                buttonPlayStop.setText(getString(R.string.play_str));
                mediaPlayer.pause();
            }

这些错误，暂停调用状态8错误（-38,0）错误（-38,0）启动调用状态0错误（-38,0）错误（-38,0）并且歌曲是不玩了。

2 个答案:

答案 0 :(得分：0)

当您调用其功能时，Media Player有自己的生命周期，确保您处于媒体播放器的正确状态enter image description here

最好的方法是制作媒体播放器服务并绑定到您活动中的该服务，并维护该服务中的所有媒体播放器方法。

http://examples.javacodegeeks.com/android/android-mediaplayer-example/

答案 1 :(得分：0)

在玩家活动中添加这些

public MusicService musicSrv ;
private boolean musicBound=false;
private ArrayList<Song> songList;

在oncreate里面

    songList = new ArrayList<Song>();
    getSongList();

在你的行为能力中添加这个     @覆盖     protected void onStart（）{         super.onStart（）; 

    if(playIntent==null){
        playIntent = new Intent(this, MusicService.class);
        this.bindService(playIntent, musicConnection, Context.BIND_AUTO_CREATE);
        this.startService(playIntent);
    }
}

private ServiceConnection musicConnection = new ServiceConnection(){


    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        MusicService.MusicBinder binder = (MusicService.MusicBinder)service;
        //get service
        musicSrv = binder.getService();
        //pass list
        musicSrv.setList(songList);
        musicBound = true;
        songTitleLabel.setText(""+musicSrv.getSongTitle());
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {
        musicBound = false;
    }
};

public void getSongList(){
    ContentResolver musicResolver = getContentResolver();
    Uri musicUri = android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    Cursor musicCursor = musicResolver.query(musicUri, null, null, null, null);
    if(musicCursor!=null && musicCursor.moveToFirst()){
        int titleColumn = musicCursor.getColumnIndex
                (android.provider.MediaStore.Audio.Media.TITLE);
        int idColumn = musicCursor.getColumnIndex
                (android.provider.MediaStore.Audio.Media._ID);
        int artistColumn = musicCursor.getColumnIndex
                (android.provider.MediaStore.Audio.Media.ARTIST);
        do {
            long thisId = musicCursor.getLong(idColumn);
            String thisTitle = musicCursor.getString(titleColumn);
            String thisArtist = musicCursor.getString(artistColumn);
            songList.add(new Song(thisId, thisTitle, thisArtist));
        }
        while (musicCursor.moveToNext());
    }
}

将列表添加到您的活动和列表项中，单击

        if(musicSrv.isPlaying()){
            if(musicSrv.status()!=null){
                musicSrv.pauseSong();
                btnPlay.setImageResource(R.drawable.btn_play);
            }
        }else{
            if(musicSrv.status()!=null){
                musicSrv.restartSong();
                btnPlay.setImageResource(R.drawable.btn_pause);
            }
        }

将此作为服务添加到您的应用中

public class MusicService extends Service实现MediaPlayer.OnPreparedListener，MediaPlayer.OnErrorListener，MediaPlayer.OnCompletionListener {     私人MediaPlayer播放器;     私人ArrayList歌曲;     private int songPosn; 

private final IBinder musicBind = new MusicBinder();
private boolean isRepeat=false;
private boolean isShuffle = false;
private int seekForwardTime = 5000;
private int seekBackwardTime = 5000;
private int currentSongIndex = 0;

@Override
public IBinder onBind(Intent arg0) {
    // TODO Auto-generated method stub
    return musicBind;
}

public void onCreate(){
    super.onCreate();
    songPosn=0;
    player = new MediaPlayer();
    initMusicPlayer();

    player.setOnPreparedListener(this);
    player.setOnCompletionListener(this);
}

public void initMusicPlayer(){
    player.setWakeMode(getApplicationContext(),
    PowerManager.PARTIAL_WAKE_LOCK);
    player.setAudioStreamType(AudioManager.STREAM_MUSIC);
    player.setOnPreparedListener(this);
    player.setOnCompletionListener(this);
    player.setOnErrorListener(this);

}

public void setList(ArrayList<Song> theSongs){
    songs=theSongs;
}

@Override
public boolean onError(MediaPlayer mp, int what, int extra) {
    return false;
}

@Override
public void onPrepared(MediaPlayer mp) {
    mp.start();
}


public class MusicBinder extends Binder {
    public MusicService getService() {
        return MusicService.this;
    }
}

public void playSong(){

    try{
        player.reset();
        System.out.println(songs);
        System.out.println(songs.get(songPosn));
        Song playSong = songs.get(songPosn);
        long currSong = playSong.getID();
        Uri trackUri = ContentUris.withAppendedId(
                MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
                currSong);
        player.setDataSource(getApplicationContext(), trackUri);
    }
    catch(Exception e){
        Log.e("MUSIC SERVICE", "Error setting data source", e);
    }
    try {
        player.prepareAsync();
    } catch (IllegalStateException e) {
        e.printStackTrace();
    }
}


public boolean isListNull()
{
    if(songs==null)
        return true;
    else
        return false;
}

public void setSong(int songIndex){
    songPosn=songIndex;
}

public boolean isPlaying()
{
    return player.isPlaying();
}

public void pauseSong()
{
    player.pause();
}

public void restartSong()
{
    player.start();
}

public String status()
{
    if(player != null)
    {
        return "sdf";
    }
    else
        return null;
}

public long getDuration()
{
    return player.getDuration();
}

public long getCurrentPosition()
{
    return player.getCurrentPosition();
}

public void seek(int currentPosition)
{
    player.seekTo(currentPosition);
}

public MediaPlayer getPlayer()
{
    return player;
}

public int getCurrentSongIndex()
{
    System.out.println(songPosn);
    return songPosn;
}

public String getSongTitle()
{
    Song song = songs.get(songPosn);
    return song.getTitle();
}

@Override
public void onCompletion(MediaPlayer arg0)
{

    if(isRepeat){
        setSong(songPosn);
        playSong();
    } else if(isShuffle){
        // shuffle is on - play a random song
        Random rand = new Random();
        songPosn = rand.nextInt((songs.size() - 1) - 0 + 1) + 0;
        setSong(songPosn);
        playSong();
    } else{
        // no repeat or shuffle ON - play next song
        if(songPosn < (songs.size() - 1)){
            setSong(songPosn + 1);
            playSong();
            songPosn = songPosn + 1;
        }else{
            // play first song
            setSong(0);
            playSong();
            songPosn = 0;
        }
    }
}

public void setRepeatSong(boolean re)
{
    isRepeat = re;
}

public void setShuffelSong(boolean sh)
{
    isShuffle = sh;
}

public void moveForward()
{
    int currentPosition = (int) getCurrentPosition();
    if(currentPosition + seekForwardTime <= getDuration()){
        seek(currentPosition + seekForwardTime);
    }else{
        seek((int)getDuration());
    }
}

public void moveBackward()
{
    int currentPosition = (int) getCurrentPosition();
    if(currentPosition - seekBackwardTime >= 0){
        seek(currentPosition - seekBackwardTime);
    }else{
       seek(0);
    }
}

public void moveNext()
{
    currentSongIndex = getCurrentSongIndex();
    if(currentSongIndex < (songs.size() - 1)){
        setSong(currentSongIndex + 1);
        playSong();
        currentSongIndex = currentSongIndex + 1;
    }else{
        setSong(0);
        playSong();
        currentSongIndex = 0;
    }
}
public void movePrevious()
{
    currentSongIndex = getCurrentSongIndex();
    if(currentSongIndex > 0){
        setSong(currentSongIndex - 1);
        playSong();
        currentSongIndex = currentSongIndex - 1;
    }else{
        // play last song
        setSong(songs.size() - 1);
        playSong();
        currentSongIndex = songs.size() - 1;
    }
}

}

和你的清单中的这些

service android：name =“.Services.MusicService”

内部应用程序标记

使用这些权限

<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />

希望这对你有用！

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