简单实现Android本地音乐播放器

public class PlayMusicService extends Service {

  //绑定服务 调用服务的方法。
  @Override
  public IBinder onBind(Intent intent) {
    return null;
  }

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  tools:context=".MainActivity" >

  <EditText
    android:id="@+id/et_path"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:hint="请输入要播放文件的路径" />

  <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

    <Button
      android:id="@+id/bt_play"
      android:onClick="play"
      android:layout_width="0dip"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="播放" />
    <Button
       android:id="@+id/bt_pause"
      android:onClick="pause"
      android:layout_width="0dip"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="暂停" />
    <Button
       android:id="@+id/bt_stop"
      android:onClick="stop"
      android:layout_width="0dip"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="停止" />
    <Button
       android:id="@+id/bt_replay"
      android:onClick="replay"
      android:layout_width="0dip"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="重播" />
  </LinearLayout>

</LinearLayout>

public class MainActivity extends Activity {
 private EditText et_path;

 private MediaPlayer mediaPlayer;

 private Button bt_play,bt_pause,bt_stop,bt_replay;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  et_path = (EditText) findViewById(R.id.et_path);
  bt_play = (Button) findViewById(R.id.bt_play);
  bt_pause = (Button) findViewById(R.id.bt_pause);
  bt_stop = (Button) findViewById(R.id.bt_stop);
  bt_replay = (Button) findViewById(R.id.bt_replay);
 }
 /**
  * 播放
  * @param view
  */
 public void play(View view) {
  String filepath = et_path.getText().toString().trim();
  File file = new File(filepath);
  if(file.exists()){
   try {
    mediaPlayer = new MediaPlayer();
    mediaPlayer.setDataSource(filepath);//设置播放的数据源。
    mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
    mediaPlayer.prepare();//准备开始播放 播放的逻辑是c代码在新的线程里面执行。
    mediaPlayer.start();
    bt_play.setEnabled(false);
    mediaPlayer.setOnCompletionListener(new OnCompletionListener() {
     @Override
     public void onCompletion(MediaPlayer mp) {
      bt_play.setEnabled(true);
     }
    });
   } catch (Exception e) {
    e.printStackTrace();
    Toast.makeText(this, "播放失败", 0).show();
   }
  }else{
   Toast.makeText(this, "文件不存在，请检查文件的路径", 0).show();
  }
 }
 /**
  * 暂停
  * @param view
  */
 public void pause(View view) {
  if("继续".equals(bt_pause.getText().toString())){
   mediaPlayer.start();
   bt_pause.setText("暂停");
   return;
  }
  if(mediaPlayer!=null&&mediaPlayer.isPlaying()){
   mediaPlayer.pause();
   bt_pause.setText("继续");
  }
 }
 /**
  * 停止
  * @param view
  */
 public void stop(View view) {
  if(mediaPlayer!=null&&mediaPlayer.isPlaying()){
   mediaPlayer.stop();
   mediaPlayer.release();
   mediaPlayer = null;
  }
  bt_pause.setText("暂停");
  bt_play.setEnabled(true);
 }
 /**
  * 重播
  * @param view
  */
 public void replay(View view) {
  if(mediaPlayer!=null&&mediaPlayer.isPlaying()){
   mediaPlayer.seekTo(0);
  }else{
   play(view);
  }
  bt_pause.setText("暂停");
 }

}