android从数据库中取音乐数据

public void getMp3(){
       list = new ArrayList<>();
       Cursor mAudioCursor = this.getContentResolver().query(
               MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
               null,// 字段　没有字段　就是查询所有信息　相当于SQL语句中的　“ * ”
               null, // 查询条件
               null, // 条件的对应?的参数
               MediaStore.Audio.AudioColumns.TITLE);// 排序方式
       // 循环输出歌曲的信息
       for (int i = 0; i < mAudioCursor.getCount(); i++) {
           mAudioCursor.moveToNext();
           // 找到歌曲标题和总时间对应的列索引
           long id = mAudioCursor.getLong(mAudioCursor.getColumnIndex(MediaStore.Audio.Media._ID)); // 音乐id
           String title = mAudioCursor.getString((mAudioCursor.getColumnIndex(MediaStore.Audio.Media.TITLE)));// 音乐标题
           String artist = mAudioCursor.getString(mAudioCursor.getColumnIndex(MediaStore.Audio.Media.ARTIST));// 艺术家
           long duration = mAudioCursor.getLong(mAudioCursor.getColumnIndex(MediaStore.Audio.Media.DURATION));// 时长
           long size = mAudioCursor.getLong(mAudioCursor.getColumnIndex(MediaStore.Audio.Media.SIZE)); // 文件大小
           String url = mAudioCursor.getString(mAudioCursor.getColumnIndex(MediaStore.Audio.Media.DATA)); // 文件路径
           int isMusic = mAudioCursor.getInt(mAudioCursor.getColumnIndex(MediaStore.Audio.Media.IS_MUSIC));// 是否为音乐
           if(isMusic!=0){//只有当是音乐的时候才保存
               Mp3Info mp3Info=new Mp3Info(id,title,artist,duration,size,url);
               list.add(mp3Info);
           }
       }

   }

package flyfish.com.mp3play;

/**
 * Created by Administrator on 2015/8/18 0018.
 */
public class Mp3Info {
    private long id;
    private String title;
    private String artist;
    private long duration;
    private long size;
    private String url;

    public Mp3Info( long id, String title,String artist, long duration, long size, String url) {
        this.artist = artist;
        this.duration = duration;
        this.id = id;
        this.size = size;
        this.title = title;
        this.url = url;
    }

    public Mp3Info() {
    }

    public String getArtist() {
        return artist;
    }

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

    public long getDuration() {
        return duration;
    }

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

    public long getId() {
        return id;
    }

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

    public long getSize() {
        return size;
    }

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

    public String getTitle() {
        return title;
    }

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

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    @Override
    public String toString() {
        return "Mp3Info{" +
                "artist='" + artist + '\'' +
                ", id=" + id +
                ", title='" + title + '\'' +
                ", duration=" + duration +
                ", size=" + size +
                ", url='" + url + '\'' +
                '}';
    }
}