初学者Android音乐播放器

以下是一个初学者Android音乐播放器的示例代码，它可以显示本地歌曲并播放，可切换下一首，上一首，具有暂停等的功能。需要注意的是，自己音乐路径配置要加/storage/...。

public class MainActivity extends AppCompatActivity {

    private MediaPlayer mediaPlayer = new MediaPlayer();
    private int position = 0;
    private List<String> musicList = new ArrayList<>();

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

        // 获取本地音乐列表
        getMusicList();

        // 播放音乐
        playMusic(position);

        // 下一首
        Button nextBtn = findViewById(R.id.next_btn);
        nextBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (position < musicList.size() - 1) {
                    position++;
                } else {
                    position = 0;
                }
                playMusic(position);
            }
        });

        // 上一首
        Button prevBtn = findViewById(R.id.prev_btn);
        prevBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (position > 0) {
                    position--;
                } else {
                    position = musicList.size() - 1;
                }
                playMusic(position);
            }
        });

        // 暂停
        Button pauseBtn = findViewById(R.id.pause_btn);
        pauseBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mediaPlayer.isPlaying()) {
                    mediaPlayer.pause();
                } else {
                    mediaPlayer.start();
                }
            }
        });
    }

    // 获取本地音乐列表
    private void getMusicList() {
        ContentResolver contentResolver = getContentResolver();
        Cursor cursor = contentResolver.query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
        if (cursor != null) {
            while (cursor.moveToNext()) {
                String path = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DATA));
                musicList.add(path);
            }
            cursor.close();
        }
    }

    // 播放音乐
    private void playMusic(int position) {
        try {
            mediaPlayer.reset();
            mediaPlayer.setDataSource(musicList.get(position));
            mediaPlayer.prepare();
            mediaPlayer.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}