目標：獲取手機中的歌曲，並使用MediaPlayer播放歌曲

第一步：建立介面卡控制元件

第二步：建立介面卡

第三步：繫結介面卡

第四步：為MediaPlayer建立播放、暫停、上一曲、下一曲、停止方法

第五步：使用Thread和SeekBar實現進度條

MainActivity

public class MainActivity extends Activity {

    private ListView musicListView;
    // 資源獲取器
    private ContentResolver resolver;
    private
 
 List<MusicVO> musicList = new ArrayList<MusicVO>();
    private MediaPlayer mediaPlayer;
    private int currentPosition;
    private Button pre;
    private Button next;
    private Button play;
    private Button stop;
    private SeekBar seekbar;
    private Thread thread;
    //執行緒標誌位
 

    private boolean isStop;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // 例項化listview
        musicListView = (ListView) findViewById(R.id.musiclistview);

        // 初始化資料
        initData();

        // 建立介面卡
 

        MusicAdapter adapter = new MusicAdapter(this, musicList);
        // 繫結介面卡
        musicListView.setAdapter(adapter);

        // 例項化MediaPlayer
        mediaPlayer = new MediaPlayer();

        // 設定點選事件
        musicListView.setOnItemClickListener(new OnItemClickListener() {
            // parent--父檢視
            // view——當前點選的View
            // position——當前點選的位置
            // id——當前點選項的ID
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                currentPosition = position;
                play();
                play.setText("暫停");
            }
        });

        initView();

        seekbar = (SeekBar) findViewById(R.id.seekbar);

    }

    private void initView() {

        pre = (Button) findViewById(R.id.prebtn);
        next = (Button) findViewById(R.id.nextbtn);
        play = (Button) findViewById(R.id.playbtn);
        stop = (Button) findViewById(R.id.stopbtn);

        // 上一曲
        pre.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                previous();
            }
        });

        // 下一曲
        next.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                next();
            }
        });

        // 播放
        play.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if (mediaPlayer.isPlaying()) {
                    // 如果正在播放，則暫停，並把按鈕上的文字設定成“播放”
                    mediaPlayer.pause();
                    play.setText("播放");
                } else {
                    // 如果已暫停，則播放，並把按鈕上的文字設定成“暫停”
                    mediaPlayer.start();
                    play.setText("暫停");
                }
            }
        });

        // 停止
        stop.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                mediaPlayer.stop();
                play.setText("播放");
                // 設定進度條歸零
                seekbar.setProgress(0);
                //執行緒標誌位，執行緒停止
                isStop = true;
            }
        });

    }

    /**
     * 初始化資料，獲取手機中的音樂檔案，並新增至list列表中
     */
    private void initData() {
        // 建立ContentResolver
        resolver = getContentResolver();
        // 建立遊標
        Cursor cursor = resolver.query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null,
                null, null);
        // 把游標移到第一位
        cursor.moveToFirst();
        for (int i = 0; i < cursor.getCount(); i++) {
            // 獲取歌曲名字
            String name = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.TITLE));
            // 獲取歌手名字
            String singer = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ARTIST));
            // 獲取歌曲的路徑
            String path = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DATA));
            // 新建一個MusicVO物件
            MusicVO music = new MusicVO();
            music.setName(name);
            music.setSinger(singer);
            music.setPath(path);
            musicList.add(music);
            //遊標下移
            cursor.moveToNext();
        }
        // 關閉遊標，釋放資源
        cursor.close();
    }

    /**
     * 播放
     */
    private void play() {
        isStop = false;
        try {
            // 重置
            mediaPlayer.reset();
            // 設定音樂播放源
            mediaPlayer.setDataSource(musicList.get(currentPosition).getPath());
            // 準備
            mediaPlayer.prepare();
            // 啟動
            mediaPlayer.start();
            // 設定播放結束後自動迴圈播放
            mediaPlayer.setOnCompletionListener(new OnCompletionListener() {

                @Override
                public void onCompletion(MediaPlayer mp) {
                    next();
                }
            });
            // 設定seekbar的最大值
            seekbar.setMax(mediaPlayer.getDuration());
            // 建立一個執行緒
            thread = new Thread(new SeekBarThread());
            // 啟動執行緒
            thread.start();
        } catch (IllegalArgumentException | SecurityException | IllegalStateException
                | IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 下一曲
     */
    private void next() {
        if (currentPosition == musicList.size() - 1) {
            currentPosition = 0;
        } else {
            currentPosition = currentPosition + 1;
        }
        play();
    }

    /**
     * 上一曲
     */
    private void previous() {
        if (currentPosition == 0) {
            currentPosition = musicList.size() - 1;
        } else {
            currentPosition = currentPosition - 1;
        }
        play();
    }

    // 自定義的執行緒
    private class SeekBarThread implements Runnable {

        @Override
        public void run() {
            while (mediaPlayer != null && isStop == false) {
                // 將SeekBar位置設定到當前播放位置
                seekbar.setProgress(mediaPlayer.getCurrentPosition());
                try {
                    // 每100毫秒更新一次位置
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }

        }

    }
}

MyAdapter

public class MusicAdapter extends BaseAdapter{

    private Context mContext;
    private List<MusicVO> mList;

    public MusicAdapter(Context context,List<MusicVO> list) {
        this.mContext = context;
        this.mList = list;
    }

    @Override
    public int getCount() {
        return mList.size();
    }

    @Override
    public Object getItem(int position) {
        return mList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = LayoutInflater.from(mContext);
        View v = inflater.inflate(R.layout.item, null);
        TextView nameText = (TextView) v.findViewById(R.id.name_view);
        TextView singerText = (TextView) v.findViewById(R.id.singer_view);
        nameText.setText(mList.get(position).getName());
        singerText.setText(mList.get(position).getSinger());
        return v;
    }

}