Android Media Player：应用程序结束后应用程序崩溃

Question

我正在使用以下代码从shoutcast服务器流式传输。它在呼叫到来时暂停流，但在呼叫结束后使应用程序崩溃。我正在使用PhoneStateListener方法。我已经在清单中添加了电话状态权限。

import java.io.IOException;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.IBinder;
import android.preference.PreferenceManager;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;
import android.util.Log;

public class ServiceRadio extends Service {
    private static final String TAG = "ServiceRadio";
    MediaPlayer mp;
    boolean isPlaying;
    SharedPreferences prefs;
    SharedPreferences.Editor editor;
    Notification n;
    NotificationManager notificationManager;
    // Change this int to some number specifically for this app
    int notifId = 5315;

    @Override
    public IBinder onBind(Intent arg0) {
        // TODO Auto-generated method stub
        return null;
    }

    @SuppressWarnings("deprecation")
    @Override
    public void onCreate() {
        super.onCreate();
        Log.d(TAG, "onCreate");

        // Init the SharedPreferences and Editor
        prefs = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        editor = prefs.edit();

        // Set up the buffering notification
        notificationManager = (NotificationManager) getApplicationContext()
                .getSystemService(NOTIFICATION_SERVICE);
        Context context = getApplicationContext();

        String notifTitle = context.getResources().getString(R.string.app_name);
        String notifMessage = context.getResources().getString(R.string.buffering);

        n = new Notification();
        n.icon = R.drawable.icon;
        n.tickerText = "Buffering";
        n.when = System.currentTimeMillis();

        Intent nIntent = new Intent(context, ActivityRadio.class);
        PendingIntent pIntent = PendingIntent.getActivity(context, 0, nIntent, 0);

        n.setLatestEventInfo(context, notifTitle, notifMessage, pIntent);

        notificationManager.notify(notifId, n);

        // It's very important that you put the IP/URL of your ShoutCast stream here
        // Otherwise you'll get Webcom Radio
        String url = "http://78.129.163.73:20426/";
        mp = new MediaPlayer();
        mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
        try {
            mp.setDataSource(url);
            mp.prepare();
        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SecurityException e) {
            // TODO Auto-generated catch block
            Log.e(TAG, "SecurityException");
        } catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            Log.e(TAG, "IllegalStateException");
        } catch (IOException e) {
            // TODO Auto-generated catch block
            Log.e(TAG, "IOException");
        }

        PhoneStateListener phoneStateListener = new PhoneStateListener() {
            @Override
            public void onCallStateChanged(int state, String incomingNumber) {
                if (state == TelephonyManager.CALL_STATE_RINGING) {
                    //INCOMING call
                    //do all necessary action to pause the audio
                    if(mp!=null){//check mp


                        if(mp.isPlaying()){ 

                            mp.pause();
                        }
                    }

                } else if(state == TelephonyManager.CALL_STATE_IDLE) {
                    //Not IN CALL
                    //do anything if the phone-state is idle

                            mp.start();


                } else if(state == TelephonyManager.CALL_STATE_OFFHOOK) {
                    //A call is dialing, active or on hold
                    //do all necessary action to pause the audio
                    //do something here
                    if(mp!=null){//check mp


                        if(mp.isPlaying()){ 

                            mp.pause();
                        }
                    }
                }
                super.onCallStateChanged(state, incomingNumber);
            }
        };//end PhoneStateListener

        TelephonyManager mgr = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);
        if(mgr != null) {
            mgr.listen(phoneStateListener, PhoneStateListener.LISTEN_CALL_STATE);
        }

    }



    @SuppressWarnings("deprecation")
    @Override
    public void onStart(Intent intent, int startId) {
        Log.d(TAG, "onStart");
        mp.start();
        // Set the isPlaying preference to true
        editor.putBoolean("isPlaying", true);
        editor.commit();

        Context context = getApplicationContext();
        String notifTitle = context.getResources().getString(R.string.app_name);
        String notifMessage = context.getResources().getString(R.string.now_playing);

        n.icon = R.drawable.icon;
        n.tickerText = notifMessage;
        n.flags = Notification.FLAG_NO_CLEAR;
        n.when = System.currentTimeMillis();

        Intent nIntent = new Intent(context, ActivityRadio.class);
        PendingIntent pIntent = PendingIntent.getActivity(context, 0, nIntent, 0);

        n.setLatestEventInfo(context, notifTitle, notifMessage, pIntent);
        // Change 5315 to some nother number
        notificationManager.notify(notifId, n);
    }

    @Override
    public void onDestroy() {
        Log.d(TAG, "onDestroy");
        mp.stop();
        mp.release();
        mp = null;
        editor.putBoolean("isPlaying", false);
        editor.commit();
        notificationManager.cancel(notifId);



    }

}