写一个功能完善的android应用播放器代码

以下是一个简单的Android应用播放器代码，包括基本的播放控制，进度条等功能。你可以根据自己的需要进行修改和扩展。

布局文件：activity_main.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">

    <SurfaceView
        android:id="@+id/surface_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true" />

    <LinearLayout
        android:id="@+id/control_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:background="#80000000"
        android:orientation="horizontal"
        android:padding="10dp">

        <ImageButton
            android:id="@+id/btn_play_pause"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:background="@null"
            android:src="@drawable/ic_play" />

        <SeekBar
            android:id="@+id/seek_bar"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:layout_weight="1"
            android:max="100"
            android:paddingLeft="10dp"
            android:paddingRight="10dp"
            android:thumb="@drawable/seekbar_thumb"
            android:thumbOffset="4dp" />

        <TextView
            android:id="@+id/text_current_time"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:textColor="#FFFFFF"
            android:textSize="12sp"
            android:text="00:00" />

        <TextView
            android:id="@+id/text_total_time"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:textColor="#FFFFFF"
            android:textSize="12sp"
            android:text="00:00" />
    </LinearLayout>

</RelativeLayout>

Java代码：MainActivity.java

public class MainActivity extends AppCompatActivity implements SurfaceHolder.Callback {

    private SurfaceView surfaceView;
    private MediaPlayer mediaPlayer;
    private SeekBar seekBar;
    private ImageButton btnPlayPause;
    private TextView textCurrentTime;
    private TextView textTotalTime;
    private Handler handler;
    private Runnable runnable;

    private boolean isPlaying = false;

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

        surfaceView = findViewById(R.id.surface_view);
        seekBar = findViewById(R.id.seek_bar);
        btnPlayPause = findViewById(R.id.btn_play_pause);
        textCurrentTime = findViewById(R.id.text_current_time);
        textTotalTime = findViewById(R.id.text_total_time);

        surfaceView.getHolder().addCallback(this);

        btnPlayPause.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mediaPlayer == null) {
                    return;
                }
                if (isPlaying) {
                    mediaPlayer.pause();
                    btnPlayPause.setImageResource(R.drawable.ic_play);
                    isPlaying = false;
                } else {
                    mediaPlayer.start();
                    btnPlayPause.setImageResource(R.drawable.ic_pause);
                    isPlaying = true;
                    updateSeekBar();
                }
            }
        });

        seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                if (fromUser && mediaPlayer != null) {
                    mediaPlayer.seekTo(progress * mediaPlayer.getDuration() / 100);
                    updateSeekBar();
                }
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                handler.removeCallbacks(runnable);
            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                updateSeekBar();
            }
        });

        handler = new Handler();
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            mediaPlayer = new MediaPlayer();
            mediaPlayer.setDataSource("http://www.hochmuth.com/mp3/Haydn_Cello_Concerto_D-1.mp3");
            mediaPlayer.setDisplay(holder);
            mediaPlayer.prepareAsync();
            mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
                @Override
                public void onPrepared(MediaPlayer mp) {
                    seekBar.setMax(100);
                    textTotalTime.setText(formatTime(mediaPlayer.getDuration()));
                }
            });
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        if (mediaPlayer != null) {
            mediaPlayer.release();
            mediaPlayer = null;
        }
    }

    private void updateSeekBar() {
        if (mediaPlayer == null) {
            return;
        }
        seekBar.setProgress(mediaPlayer.getCurrentPosition() * 100 / mediaPlayer.getDuration());
        textCurrentTime.setText(formatTime(mediaPlayer.getCurrentPosition()));
        if (mediaPlayer.isPlaying()) {
            runnable = new Runnable() {
                @Override
                public void run() {
                    updateSeekBar();
                }
            };
            handler.postDelayed(runnable, 1000);
        }
    }

    private String formatTime(int time) {
        SimpleDateFormat format = new SimpleDateFormat("mm:ss");
        return format.format(new Date(time));
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        handler.removeCallbacks(runnable);
    }
}