Question

我制作了一个显示歌曲列表的简单应用，并计划在点击时让每个列表项播放歌曲。然而，我已经把一切都搞定了，音乐不会开始播放。如何使用MediaPlayer播放ContentResolver中的歌曲？我已经设置了一个示例代码供您查看。如果可能的话，有一些样品或例子是很荣幸的。

public class MainActivity extends ActionBarActivity {
    List tracks;
    String[] ColId;
    List<Track>tack;
    private MediaPlayer mMediaPlayer;

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


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        tracks = Track.getItems(this);
        ColId = Track.COLUMNS;

        ListView trackList = (ListView)findViewById(R.id.listView);
        ListTrackAdapter adapter = new ListTrackAdapter(this, tracks);

        trackList.setAdapter(adapter);

        trackList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {



                //long //id = 0;/* retrieve it from somewhere */;
                Uri contentUri = ContentUris.withAppendedId(
                        android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, position);


                try {
                    mMediaPlayer = new MediaPlayer();
                    mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
                    mMediaPlayer.setDataSource(MainActivity.this, contentUri);
                    mMediaPlayer.prepare();
                    mMediaPlayer.start();



                } catch (IOException e) {
                    e.printStackTrace();
                }
                String pos = String.valueOf(tracks.get(position));
                Toast.makeText(MainActivity.this,position+" = "+ColId[0],Toast.LENGTH_SHORT).show();

            }
        });


        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    protected void onPause() {
        super.onPause();
if(mMediaPlayer.isPlaying()) {
    mMediaPlayer.release();
    mMediaPlayer.stop();
}

    }


    @Override
    protected void onDestroy() {
        super.onDestroy();
        if(mMediaPlayer.isPlaying()) {
            mMediaPlayer.release();
            mMediaPlayer.stop();
        }

    }
}

Track的课程

public class Track {

    public long     id;            
    public long     albumId;       
    public long     artistId;      
    public String   path;          
    public String   title;        
    public String   album;        
    public String   artist;       
    public Uri uri;            // URI
    public long     duration;      
    public int      trackNo;       



    public static final String[] COLUMNS = {
            MediaStore.Audio.Media._ID,
            MediaStore.Audio.Media.DATA,
            MediaStore.Audio.Media.TITLE,
            MediaStore.Audio.Media.ALBUM,
            MediaStore.Audio.Media.ARTIST,
            MediaStore.Audio.Media.ALBUM_ID,
            MediaStore.Audio.Media.ARTIST_ID,
            MediaStore.Audio.Media.DURATION,
            MediaStore.Audio.Media.TRACK,
    };


    public  Track(Cursor cursor)
    {
        id              = cursor.getLong( cursor.getColumnIndex( MediaStore.Audio.Media._ID ));
        path            = cursor.getString( cursor.getColumnIndex(MediaStore.Audio.Media.DATA));
        title           = cursor.getString( cursor.getColumnIndex( MediaStore.Audio.Media.TITLE ));
        album           = cursor.getString( cursor.getColumnIndex( MediaStore.Audio.Media.ALBUM ));
        artist          = cursor.getString( cursor.getColumnIndex( MediaStore.Audio.Media.ARTIST ));
        albumId         = cursor.getLong( cursor.getColumnIndex( MediaStore.Audio.Media.ALBUM_ID ));
        artistId        = cursor.getLong( cursor.getColumnIndex( MediaStore.Audio.Media.ARTIST_ID ));
        duration        = cursor.getLong( cursor.getColumnIndex( MediaStore.Audio.Media.DURATION ));
        trackNo         = cursor.getInt( cursor.getColumnIndex( MediaStore.Audio.Media.TRACK ));
        uri             = ContentUris.withAppendedId(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, id);
    }



    public static List getItems(Context activity) {

        List tracks = new ArrayList();
        ContentResolver resolver = activity.getContentResolver();
        Cursor cursor = resolver.query(
                MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
                Track.COLUMNS,
                null,
                null,
                null
        );
        while( cursor.moveToNext() ){
            if( cursor.getLong(cursor.getColumnIndex( MediaStore.Audio.Media.DURATION)) < 3000 ){continue;}
            tracks.add(new Track(cursor));
        }
        cursor.close();
        return tracks;
    }



}

Answer 1

试试这个，

$r = mysql_fetch_assoc($result);

$myvar = $r['something'];

替换为

mMediaPlayer.setDataSource(MainActivity.this, contentUri);

然后它运作正常。

如何在Android中播放Cursor的歌曲？

1 个答案: