Android使用ListView实现播放列表和音乐播放器的代码和单布局代码

好的，下面是一个简单的Android音乐播放器的代码示例，包含了列表展示和音乐播放功能：

1. 首先是布局文件，这里使用了ListView来展示音乐列表，一个Button用于播放音乐：

<!-- activity_music.xml -->
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ListView
        android:id="@+id/music_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/play_button" />

    <Button
        android:id="@+id/play_button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:text="Play" />

</RelativeLayout>

2. 接下来是单个列表项的布局文件，包含了音乐名称和时长的展示：

<!-- music_item.xml -->
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <TextView
        android:id="@+id/music_name"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="Music Name" />

    <TextView
        android:id="@+id/music_duration"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="00:00" />

</LinearLayout>

3. 接下来是Java代码，首先是Music类，用于保存音乐名称和时长信息：

// Music.java
public class Music {
    private String name;
    private long duration;

    public Music(String name, long duration) {
        this.name = name;
        this.duration = duration;
    }

    public String getName() {
        return name;
    }

    public long getDuration() {
        return duration;
    }
}

4. 接下来是MusicAdapter类，用于将Music数据绑定到ListView的列表项上：

// MusicAdapter.java
public class MusicAdapter extends ArrayAdapter<Music> {
    public MusicAdapter(Context context, List<Music> musicList) {
        super(context, 0, musicList);
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.music_item, parent, false);
        }

        Music music = getItem(position);

        TextView musicNameView = convertView.findViewById(R.id.music_name);
        TextView musicDurationView = convertView.findViewById(R.id.music_duration);

        musicNameView.setText(music.getName());
        musicDurationView.setText(formatDuration(music.getDuration()));

        return convertView;
    }

    private String formatDuration(long duration) {
        long minutes = TimeUnit.MILLISECONDS.toMinutes(duration);
        long seconds = TimeUnit.MILLISECONDS.toSeconds(duration) - TimeUnit.MINUTES.toSeconds(minutes);
        return String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds);
    }
}

5. 最后是MusicActivity类，用于展示音乐列表和播放音乐：

// MusicActivity.java
public class MusicActivity extends AppCompatActivity {

    private List<Music> musicList = new ArrayList<>();
    private MediaPlayer mediaPlayer;
    private ListView musicListView;
    private Button playButton;

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

        // 初始化音乐列表
        musicList.add(new Music("Music 1", 10000));
        musicList.add(new Music("Music 2", 20000));
        musicList.add(new Music("Music 3", 30000));

        // 初始化列表适配器
        MusicAdapter adapter = new MusicAdapter(this, musicList);

        // 初始化ListView并设置适配器
        musicListView = findViewById(R.id.music_list);
        musicListView.setAdapter(adapter);

        // 初始化播放按钮
        playButton = findViewById(R.id.play_button);
        playButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mediaPlayer == null) {
                    mediaPlayer = MediaPlayer.create(MusicActivity.this, R.raw.music);
                    mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
                        @Override
                        public void onCompletion(MediaPlayer mp) {
                            stopMusic();
                        }
                    });
                }

                if (mediaPlayer.isPlaying()) {
                    pauseMusic();
                } else {
                    startMusic();
                }
            }
        });

        // 初始化音频焦点监听器
        AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
        audioManager.requestAudioFocus(new AudioManager.OnAudioFocusChangeListener() {
            @Override
            public void onAudioFocusChange(int focusChange) {
                switch (focusChange) {
                    case AudioManager.AUDIOFOCUS_GAIN:
                        // 恢复音乐播放
                        if (mediaPlayer != null) {
                            mediaPlayer.setVolume(1.0f, 1.0f);
                            mediaPlayer.start();
                        }
                        break;
                    case AudioManager.AUDIOFOCUS_LOSS:
                        // 停止音乐播放
                        stopMusic();
                        break;
                    case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
                        // 暂停音乐播放
                        pauseMusic();
                        break;
                    case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
                        // 降低音量
                        if (mediaPlayer != null) {
                            mediaPlayer.setVolume(0.2f, 0.2f);
                        }
                        break;
                }
            }
        }, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN);
    }

    private void startMusic() {
        if (mediaPlayer != null) {
            mediaPlayer.start();
            playButton.setText(R.string.pause);
        }
    }

    private void pauseMusic() {
        if (mediaPlayer != null) {
            mediaPlayer.pause();
            playButton.setText(R.string.play);
        }
    }

    private void stopMusic() {
        if (mediaPlayer != null) {
            mediaPlayer.stop();
            mediaPlayer.release();
            mediaPlayer = null;
            playButton.setText(R.string.play);
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        stopMusic();
    }
}

这个示例演示了如何使用ListView实现音乐播放器和播放列表。在实际应用中，您还需要添加一些额外的功能，如从本地文件获取音乐文件、添加删除音乐等。