MediaPlayer 报 start called in state 1

package com.ncu.thorgame.service;


import java.io.IOException;


import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Environment;
import android.os.IBinder;
import android.widget.Toast;


public class MusicService extends Service {
MediaPlayer player = new MediaPlayer();


@Override
public void onCreate() {
// TODO Auto-generated method stub
super.onCreate();
}


@Override
public int onStartCommand(Intent intent, int flags, int startId) {
        System.out.println("sd");
play();
return super.onStartCommand(intent, flags, startId);
}


@Override
public IBinder onBind(Intent arg0) {
return null;
}


private void play() {
if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {


         System.out.println("sd");
    try {
player.setDataSource(Environment.getExternalStorageDirectory()+ "/z.mp3");
player.prepare();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
       player.setLooping(true);  
player.start();  

} else {
Toast.makeText(getApplicationContext(), "SD卡没准备好", Toast.LENGTH_LONG).show();
}
}

}

基本无误  花了很久 时间   对照网上的百度出的解决方法 都对我没用

后来发现 还是  读外部sd 权限没给      希望大家以后不用心急

在AndroidManifest.xml 中 加入

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