Android音乐播放器代码编写

以下是Android音乐播放器代码编写的一些基本步骤和注意事项：

1. 首先需要在AndroidManifest.xml文件中添加权限：

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

2. 在布局文件中添加音乐播放器的UI界面，例如：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/layout_music_player"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white">

    <ImageView
        android:id="@+id/iv_music_cover"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scaleType="centerCrop" />

    <TextView
        android:id="@+id/tv_music_title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:background="@color/black_alpha_50"
        android:gravity="center_vertical"
        android:padding="10dp"
        android:singleLine="true"
        android:textColor="@color/white"
        android:textSize="16sp" />

    <LinearLayout
        android:id="@+id/layout_music_control"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@id/tv_music_title"
        android:gravity="center_vertical"
        android:orientation="horizontal"
        android:padding="10dp">

        <ImageView
            android:id="@+id/iv_music_play"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/ic_play_arrow_black_24dp" />

        <ImageView
            android:id="@+id/iv_music_pause"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/ic_pause_black_24dp"
            android:visibility="gone" />

        <SeekBar
            android:id="@+id/sb_music_progress"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:max="100"
            android:paddingLeft="10dp"
            android:paddingRight="10dp"
            android:thumb="@drawable/seekbar_thumb"
            android:thumbOffset="0dp" />

        <TextView
            android:id="@+id/tv_music_duration"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="@color/white"
            android:textSize="12sp" />

    </LinearLayout>

</RelativeLayout>

3. 在Activity中初始化音乐播放器，并设置相关监听器，例如：

public class MusicPlayerActivity extends AppCompatActivity implements View.OnClickListener {

    private MediaPlayer mMediaPlayer;
    private ImageView mIvPlay;
    private ImageView mIvPause;
    private SeekBar mSbProgress;
    private TextView mTvDuration;

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

        mMediaPlayer = new MediaPlayer();
        mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mMediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
            @Override
            public void onPrepared(MediaPlayer mp) {
                mSbProgress.setMax(mMediaPlayer.getDuration());
                mTvDuration.setText(formatTime(mMediaPlayer.getDuration()));
                mMediaPlayer.start();
                mIvPlay.setVisibility(View.GONE);
                mIvPause.setVisibility(View.VISIBLE);
            }
        });
        mMediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mp) {
                mIvPlay.setVisibility(View.VISIBLE);
                mIvPause.setVisibility(View.GONE);
            }
        });

        mIvPlay = findViewById(R.id.iv_music_play);
        mIvPause = findViewById(R.id.iv_music_pause);
        mSbProgress = findViewById(R.id.sb_music_progress);
        mTvDuration = findViewById(R.id.tv_music_duration);

        mIvPlay.setOnClickListener(this);
        mIvPause.setOnClickListener(this);
        mSbProgress.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                if (fromUser) {
                    mMediaPlayer.seekTo(progress);
                }
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.iv_music_play:
                try {
                    mMediaPlayer.setDataSource("音乐文件路径");
                    mMediaPlayer.prepareAsync();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                break;
            case R.id.iv_music_pause:
                if (mMediaPlayer.isPlaying()) {
                    mMediaPlayer.pause();
                    mIvPlay.setVisibility(View.VISIBLE);
                    mIvPause.setVisibility(View.GONE);
                }
                break;
        }
    }

    private String formatTime(int duration) {
        int minute = duration / 1000 / 60;
        int second = duration / 1000 % 60;
        return String.format(Locale.getDefault(), "%02d:%02d", minute, second);
    }

}

4. 在AndroidManifest.xml文件中注册Activity：

<activity android:name=".MusicPlayerActivity" />