ANDROID - 使用CursorLoader获取音频会导致音频重复

Question

我正在构建一个活动，我希望使用Loader填充音频。

public class MainActivity extends BaseActivity implements 
    LoaderManager.LoaderCallbacks<Cursor> {

    private static final int INTERNAL_CURSOR_ID = 0;
    private static final int EXTERNAL_CURSOR_ID = 1;

    private ArrayList<Audio> audios = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initLoader();
    }  

    private void initLoader() {
        try {
           getSupportLoaderManager().initLoader(INTERNAL_CURSOR_ID, null, this);
           getSupportLoaderManager().initLoader(EXTERNAL_CURSOR_ID, null, this);
        } catch (SecurityException e) {
        } catch (IllegalArgumentException e) {
        }
    }

     private static final String[] INTERNAL_COLUMNS = new String[]{
           MediaStore.Audio.Media._ID,
           MediaStore.Audio.Media.ALBUM,
           MediaStore.Audio.Media.ARTIST,
           MediaStore.Audio.Media.COMPOSER,
           MediaStore.Audio.Media.DATA,
           MediaStore.Audio.Media.DATE_ADDED,
           MediaStore.Audio.Media.DATE_MODIFIED,
           MediaStore.Audio.Media.DISPLAY_NAME,
           MediaStore.Audio.Media.DURATION,
           MediaStore.Audio.Media.IS_ALARM,
           MediaStore.Audio.Media.IS_MUSIC,
           MediaStore.Audio.Media.IS_NOTIFICATION,
           MediaStore.Audio.Media.IS_PODCAST,
           MediaStore.Audio.Media.IS_RINGTONE,
           MediaStore.Audio.Media.MIME_TYPE,
           MediaStore.Audio.Media.SIZE,
           MediaStore.Audio.Media.TITLE
    };

    private static final String[] EXTERNAL_COLUMNS = new String[]{
           MediaStore.Audio.Media._ID,
           MediaStore.Audio.Media.ALBUM,
           MediaStore.Audio.Media.ARTIST,
           MediaStore.Audio.Media.COMPOSER,
           MediaStore.Audio.Media.DATA,
           MediaStore.Audio.Media.DATE_ADDED,
           MediaStore.Audio.Media.DATE_MODIFIED,
           MediaStore.Audio.Media.DISPLAY_NAME,
           MediaStore.Audio.Media.DURATION,
           MediaStore.Audio.Media.IS_ALARM,
           MediaStore.Audio.Media.IS_MUSIC,
           MediaStore.Audio.Media.IS_NOTIFICATION,
           MediaStore.Audio.Media.IS_PODCAST,
           MediaStore.Audio.Media.IS_RINGTONE,
           MediaStore.Audio.Media.MIME_TYPE,
           MediaStore.Audio.Media.SIZE,
           MediaStore.Audio.Media.TITLE
    };

    @Override
    public Loader<Cursor> onCreateLoader(int id, Bundle args) {
        ArrayList<String> selectionArgsList = new ArrayList<String>();
        String selection;
        Uri baseUri;
        String[] projection;
        switch (id) {
            case INTERNAL_CURSOR_ID:
                baseUri = MediaStore.Audio.Media.INTERNAL_CONTENT_URI;
                projection = INTERNAL_COLUMNS;
                break;
            case EXTERNAL_CURSOR_ID:
                baseUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
                projection = EXTERNAL_COLUMNS;
                break;
            default:
                return null;
        }
        selection = "(_DATA LIKE ?)";
        selectionArgsList.add("%");
        String[] selectionArgs = selectionArgsList.toArray(new String[selectionArgsList.size()]);
        return new CursorLoader(this, baseUri, projection, selection, selectionArgs,
            MediaStore.Audio.Media.DEFAULT_SORT_ORDER);
    }  

    @Override
    public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
        if (data == null) {
            return;
        }
        if (data.moveToFirst()) {
            do {

                int id = data.getInt(data.getColumnIndexOrThrow(MediaStore.Audio.Media._ID));
                String album = data.getString(data.getColumnIndexOrThrow(MediaStore.Audio.Media.ALBUM));
                String artist = data.getString(data.getColumnIndexOrThrow(MediaStore.Audio.Media.ARTIST));
                String composer =
                    data.getString(data.getColumnIndexOrThrow(MediaStore.Audio.Media.COMPOSER));
                String _data = data.getString(data.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA));
                int dateAdded = data.getInt(data.getColumnIndexOrThrow(MediaStore.Audio.Media.DATE_ADDED));
                int dateModified =
                    data.getInt(data.getColumnIndexOrThrow(MediaStore.Audio.Media.DATE_MODIFIED));
                String displayName =
                    data.getString(data.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME));
                int duration = data.getInt(data.getColumnIndexOrThrow(MediaStore.Audio.Media.DURATION));
                int isAlarm = data.getInt(data.getColumnIndexOrThrow(MediaStore.Audio.Media.IS_ALARM));
                int isMusic = data.getInt(data.getColumnIndexOrThrow(MediaStore.Audio.Media.IS_MUSIC));
                int isNotification =
                    data.getInt(data.getColumnIndexOrThrow(MediaStore.Audio.Media.IS_NOTIFICATION));
                int isPodcast = data.getInt(data.getColumnIndexOrThrow(MediaStore.Audio.Media.IS_PODCAST));
                int isRingtone =
                    data.getInt(data.getColumnIndexOrThrow(MediaStore.Audio.Media.IS_RINGTONE));
                String mimeType =
                    data.getString(data.getColumnIndexOrThrow(MediaStore.Audio.Media.MIME_TYPE));
                int size = data.getInt(data.getColumnIndexOrThrow(MediaStore.Audio.Media.SIZE));
                String title = data.getString(data.getColumnIndexOrThrow(MediaStore.Audio.Media.TITLE));
                String folderName = new File(new File(_data).getParent()).getName();
                String folderPath = new File(_data).getParent();

                Audio audio = new Audio();
                audio.setId(id);
                audio.setAlbum(album);
                audio.setArtist(artist);
                audio.setComposer(composer);
                audio.setData(_data);
                audio.setDateAdded(dateAdded);
                audio.setDateModified(dateModified);
                audio.setDisplayName(displayName);
                audio.setDuration(duration);
                audio.setIsAlarm(isAlarm);
                audio.setIsMusic(isMusic);
                audio.setIsNotification(isNotification);
                audio.setIsPodcast(isPodcast);
                audio.setIsRingtone(isRingtone);
                audio.setMimeType(mimeType);
                audio.setSize(size);
                audio.setTitle(title);

                audios.add(audio);
            } while (data.moveToNext());
        }
        this.runOnUiThread(new Runnable() {
            @Override
            public void run() {
                // update audios to RecyclerView
            }
        });
     }

这是型号：Audio.class：

public class Audio implements Parcelable {
  private int id;
  private String album;
  private String artist;
  private String composer;
  private String data;
  private int dateAdded;
  private int dateModified;
  private String displayName;
  private int duration;
  private int isAlarm;
  private int isMusic;
  private int isNotification;
  private int isPodcast;
  private int isRingtone;
  private String mimeType;
  private int size;
  private String title;

  public Audio() {
  }

  protected Audio(Parcel in) {
    id = in.readInt();
    album = in.readString();
    artist = in.readString();
    composer = in.readString();
    data = in.readString();
    dateAdded = in.readInt();
    dateModified = in.readInt();
    displayName = in.readString();
    duration = in.readInt();
    isAlarm = in.readInt();
    isMusic = in.readInt();
    isNotification = in.readInt();
    isPodcast = in.readInt();
    isRingtone = in.readInt();
    mimeType = in.readString();
    size = in.readInt();
    title = in.readString();
  }

  public static final Creator<Audio> CREATOR = new Creator<Audio>() {
    @Override 
    public Audio createFromParcel(Parcel in) {
      return new Audio(in);
    }

    @Override 
    public Audio[] newArray(int size) {
      return new Audio[size];
    }
  };

  @Override 
  public boolean equals(Object o) {
    if (this == o) return true;
    if (!(o instanceof Audio)) return false;
    Audio photo = (Audio) o;
    return id == photo.id;
  }

  @Override 
  public int hashCode() {
    return id;
  }

  public int getId() {
    return id;
  }

  public void setId(int id) {
    this.id = id;
  }

  public String getAlbum() {
    return album;
  }

  public void setAlbum(String album) {
    this.album = album;
  }

  public String getArtist() {
    return artist;
  }

  public void setArtist(String artist) {
    this.artist = artist;
  }

  public String getComposer() {
    return composer;
  }

  public void setComposer(String composer) {
    this.composer = composer;
  }

  public String getData() {
    return data;
  }

  public void setData(String data) {
    this.data = data;
  }

  public int getDateAdded() {
    return dateAdded;
  }

  public void setDateAdded(int dateAdded) {
    this.dateAdded = dateAdded;
  }

  public int getDateModified() {
    return dateModified;
  }

  public void setDateModified(int dateModified) {
    this.dateModified = dateModified;
  }

  public String getDisplayName() {
    return displayName;
  }

  public void setDisplayName(String displayName) {
    this.displayName = displayName;
  }

  public int getDuration() {
    return duration;
  }

  public void setDuration(int duration) {
    this.duration = duration;
  }

  public int getIsAlarm() {
    return isAlarm;
  }

  public void setIsAlarm(int isAlarm) {
    this.isAlarm = isAlarm;
  }

  public int getIsMusic() {
    return isMusic;
  }

  public void setIsMusic(int isMusic) {
    this.isMusic = isMusic;
  }

  public int getIsNotification() {
    return isNotification;
  }

  public void setIsNotification(int isNotification) {
    this.isNotification = isNotification;
  }

  public int getIsPodcast() {
    return isPodcast;
  }

  public void setIsPodcast(int isPodcast) {
    this.isPodcast = isPodcast;
  }

  public int getIsRingtone() {
    return isRingtone;
  }

  public void setIsRingtone(int isRingtone) {
    this.isRingtone = isRingtone;
  }

  public String getMimeType() {
    return mimeType;
  }

  public void setMimeType(String mimeType) {
    this.mimeType = mimeType;
  }

  public int getSize() {
    return size;
  }

  public void setSize(int size) {
    this.size = size;
  }

  public String getTitle() {
    return title;
  }

  public void setTitle(String title) {
    this.title = title;
  }

  @Override public int describeContents() {
    return 0;
  }

  @Override public void writeToParcel(Parcel parcel, int i) {
    parcel.writeInt(id);
    parcel.writeString(album);
    parcel.writeString(artist);
    parcel.writeString(composer);
    parcel.writeString(data);
    parcel.writeInt(dateAdded);
    parcel.writeInt(dateModified);
    parcel.writeString(displayName);
    parcel.writeInt(duration);
    parcel.writeInt(isAlarm);
    parcel.writeInt(isMusic);
    parcel.writeInt(isNotification);
    parcel.writeInt(isPodcast);
    parcel.writeInt(isRingtone);
    parcel.writeString(mimeType);
    parcel.writeInt(size);
    parcel.writeString(title);
  }
}

为什么光标会为所有音频返回重复项？或者设备上是否存在导致返回这些重复项的内容。