Android 使用新参数打开同一活动

在问我的问题之前，我搜索了很多地方，尝试了很多方法，但都没有一种方法适合我。 我在做一个收音机播放机！因此，我有一个列表视图，其中包含一个电台列表，每个项目都包含一些信息以及单击该项目时要播放的链接

因此，当点击一个项目时，我创建了一个包含玩家的新活动（玩家将启动一个新的服务来播放流） 当我单击返回列表视图时，播放器的活动将从堆栈中删除。 当我点击通知时，应用程序崩溃，因为找不到活动。 我已尝试覆盖BackButton，但当我单击back时，应用程序将返回主屏幕：

@Override
public void onBackPressed() {
   Log.d("CDA", "onBackPressed Called");
   Intent setIntent = new Intent(Intent.ACTION_MAIN);
   setIntent.addCategory(Intent.CATEGORY_HOME);
   setIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
   startActivity(setIntent);
}

在开始之前，我尝试在意图中添加一些标志！但它也不会起作用！！ 所以，我完全被阻塞了，找不到任何方法来处理这个问题 谢谢你的帮助！ 如果你想要一些源代码，请告诉我我会更新我的帖子！ 谢谢 更新：日志：

07-27 00:02:20.650: E/dalvikvm(9406): The following issues were seen:
07-27 00:02:22.390: E/AndroidRuntime(9406): FATAL EXCEPTION: main
07-27 00:02:22.390: E/AndroidRuntime(9406): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.MSoft.socialradio/com.MSoft.socialradio.StationListenActivity}: java.lang.NullPointerException
07-27 00:02:22.390: E/AndroidRuntime(9406):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2245)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2295)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at android.app.ActivityThread.access$700(ActivityThread.java:150)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1280)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at android.os.Looper.loop(Looper.java:176)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at android.app.ActivityThread.main(ActivityThread.java:5279)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at java.lang.reflect.Method.invokeNative(Native Method)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at java.lang.reflect.Method.invoke(Method.java:511)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at dalvik.system.NativeStart.main(Native Method)
07-27 00:02:22.390: E/AndroidRuntime(9406): Caused by: java.lang.NullPointerException
07-27 00:02:22.390: E/AndroidRuntime(9406):     at com.MSoft.socialradio.StationListenActivity.onCreate(StationListenActivity.java:91)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at android.app.Activity.performCreate(Activity.java:5267)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1097)
07-27 00:02:22.390: E/AndroidRuntime(9406):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2209)
07-27 00:02:22.390: E/AndroidRuntime(9406):     ... 11 more
07-27 00:02:31.900: E/AndroidRuntime(10122): FATAL EXCEPTION: main
07-27 00:02:31.900: E/AndroidRuntime(10122): java.lang.RuntimeException: Unable to start service com.MSoft.socialradio.MyMediaPlayerService@210972d0 with null: java.lang.NullPointerException
07-27 00:02:31.900: E/AndroidRuntime(10122):    at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2757)
07-27 00:02:31.900: E/AndroidRuntime(10122):    at android.app.ActivityThread.access$2000(ActivityThread.java:150)
07-27 00:02:31.900: E/AndroidRuntime(10122):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1383)
07-27 00:02:31.900: E/AndroidRuntime(10122):    at android.os.Handler.dispatchMessage(Handler.java:99)
07-27 00:02:31.900: E/AndroidRuntime(10122):    at android.os.Looper.loop(Looper.java:176)
07-27 00:02:31.900: E/AndroidRuntime(10122):    at android.app.ActivityThread.main(ActivityThread.java:5279)
07-27 00:02:31.900: E/AndroidRuntime(10122):    at java.lang.reflect.Method.invokeNative(Native Method)
07-27 00:02:31.900: E/AndroidRuntime(10122):    at java.lang.reflect.Method.invoke(Method.java:511)
07-27 00:02:31.900: E/AndroidRuntime(10122):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
07-27 00:02:31.900: E/AndroidRuntime(10122):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
07-27 00:02:31.900: E/AndroidRuntime(10122):    at dalvik.system.NativeStart.main(Native Method)
07-27 00:02:31.900: E/AndroidRuntime(10122): Caused by: java.lang.NullPointerException
07-27 00:02:31.900: E/AndroidRuntime(10122):    at com.MSoft.socialradio.MyMediaPlayerService.onStartCommand(MyMediaPlayerService.java:51)
07-27 00:02:31.900: E/AndroidRuntime(10122):    at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2740)
07-27 00:02:31.900: E/AndroidRuntime(10122):    ... 10 more

发球队员：

package com.MSoft.socialradio;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Timer;
import java.util.TimerTask;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.ConnectTimeoutException;
import org.apache.http.impl.client.DefaultHttpClient;

import android.annotation.SuppressLint;
import android.app.Notification;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Intent;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnBufferingUpdateListener;
import android.media.MediaPlayer.OnErrorListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.os.AsyncTask;
import android.os.IBinder;
import android.util.Log;
import android.widget.TextView;

public class MyMediaPlayerService extends Service implements OnPreparedListener, OnErrorListener, OnBufferingUpdateListener {

    Timer timer ;
    TextView songName;
    String GetSongInfo;
    MetadataTask metaTask=null;
    private MediaPlayer mediaPlayer = null;
    private boolean      isPlaying = false;
    String url;
    private static int classID = 579; // just a number

    public static String START_PLAY = "START_PLAY";
    final static String MY_ACTION = "IcyData";
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        if (intent.getBooleanExtra(START_PLAY, false)) {
            url=intent.getStringExtra("url");
            play();  




        }
        return Service.START_STICKY;    
    }



    private void play() {
        if (!isPlaying) {           
            isPlaying = true;

            Intent intent = new Intent(this, StationListenActivity.class);
            intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);

            PendingIntent pi = PendingIntent.getActivity(this, 0, intent, 0);

            Notification notification = new Notification.Builder(getApplicationContext())
                .setContentTitle("Social Radio")
                .setContentText("Now Playing:under Construction")
                .setSmallIcon(R.drawable.ic_launcher)
                .setContentIntent(pi)
                .build();

            /*mediaPlayer = MediaPlayer.create(this, R.raw.rehab); // change this for your file
            mediaPlayer.setLooping(true); // this will make it loop forever
            mediaPlayer.start();*/
            //url = "http://ice.abradio.cz:80/hit90128.mp3"; // your URL here
            Log.i("play","playing:"+url);
            try {
                 mediaPlayer = new MediaPlayer();
                    mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
                    mediaPlayer.setVolume(100, 100);
                    mediaPlayer.setDataSource(url);
                    mediaPlayer.setOnPreparedListener(this);
                    mediaPlayer.prepareAsync();
                    mediaPlayer.setOnErrorListener(this);

                    mediaPlayer.setOnBufferingUpdateListener(this);
            } catch (Exception e) {

            }



            startForeground(classID, notification);
        }
    }

    @Override
    public void onDestroy() {
        Log.i("on Destory","Stopping");
        stop();
        //timer.cancel();
    }   

    private void stop() {
        if (isPlaying) {
            Log.i("on Destory","Stopping");
            isPlaying = false;
            if (mediaPlayer != null) {
                mediaPlayer.release();
                mediaPlayer = null;
            }
            stopForeground(true);
        }
    }

    @Override
    public void onBufferingUpdate(MediaPlayer arg0, int arg1) {
        // TODO Auto-generated method stub

    }

    @Override
    public boolean onError(MediaPlayer arg0, int arg1, int arg2) {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public void onPrepared(MediaPlayer arg0) {
        mediaPlayer.start();
        StartTimer();
    }
    public InputStream OpenHttpPOSTConnection(String url) {
        InputStream inputStream = null;
        try {
            HttpClient httpclient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);

            // ---the key/value pairs to post to the server---

            HttpResponse httpResponse = httpclient.execute(httpPost);

            inputStream = httpResponse.getEntity().getContent();

        } catch (ConnectTimeoutException e) {
            Log.d("OpenHttpPOSTConnection TIMEOUT", e.getLocalizedMessage());
        } catch (Exception e) {
            Log.d("OpenHttpPOSTConnection", e.getLocalizedMessage());
        }
        return inputStream;
    }
    public void StartTimer() 
    {
        try {
            final URL Url = new URL(url);
            Log.i("StartTimer",url);
            new Thread(new Runnable() {

                @Override
                public void run() {
                    while(mediaPlayer!=null)
                    {
                    try {
                        Log.i("StartTimer","Sending:");

                        metaTask=new MetadataTask();
                        metaTask.execute(Url);
                        Intent intent_braodcast = new Intent();
                        intent_braodcast.setAction(MY_ACTION);

                           intent_braodcast.putExtra("DATAPASSED", GetSongInfo);

                           sendBroadcast(intent_braodcast); 
                           Log.i("StartTimer","Sending:");
                        Thread.sleep(5000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }

                    }
                }
            }).start();


        } catch (Exception e) {
            Log.i("StartTimer Exception","");
        }

    }
    protected class MetadataTask extends AsyncTask<URL, Void, IcyStreamMeta> {
        protected  IcyStreamMeta streamMeta;

        @Override
        protected IcyStreamMeta doInBackground(URL... urls) {

            try {
                if (OpenHttpPOSTConnection(urls[0].toString()) == null) {
                    //songName.setText("Error in connection");

                    throw new Exception("Error network");
                }
                streamMeta = new IcyStreamMeta(urls[0]);
                if (streamMeta == null) {
                    //songName.setText("Error in connection");
                    throw new Exception("Error in connection");
                }
                streamMeta.refreshMeta();
            } catch (IOException e) {
                // TODO: Handle
                Log.e(MetadataTask.class.toString(), e.getMessage());
            } catch (Exception e) {
                // TODO Auto-generated catch block
                Log.i("ExceptionDoinBackground", e.getLocalizedMessage());
            }
            return streamMeta;
        }

        @Override
        protected void onPostExecute(IcyStreamMeta result) {
            //super.onPostExecute(result);
            try {
                if (streamMeta.GetFullData() == "")
                    GetSongInfo="No Icy Data";
                else {
                    GetSongInfo=streamMeta.GetFullData();
                    //songName.setText(streamMeta.GetFullData());
                    Log.i("Onposteexecute", streamMeta.GetFullData());
                }

                // txtArtist.setText(streamMeta.getArtist());
                // txtTitle.setText(streamMeta.getTitle());
            } catch (IOException e) {
                // TODO: Handle
                Log.e(MetadataTask.class.toString(), e.getMessage());
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}

package com.MSoft.socialradio；
导入java.io.IOException；
导入java.io.InputStream；
导入java.net.MalformedURLException；
导入java.net.URL；
导入java.util.Timer；
导入java.util.TimerTask；
导入org.apache.http.HttpResponse；
导入org.apache.http.client.HttpClient；
导入org.apache.http.client.methods.HttpPost；
导入org.apache.http.conn.ConnectTimeoutException；
导入org.apache.http.impl.client.DefaultHttpClient；
导入android.annotation.SuppressLint；
导入android.app.Notification；
导入android.app.pendingent；
导入android.app.Service；
导入android.content.Intent；
导入android.media.AudioManager；
导入android.media.MediaPlayer；
导入android.media.MediaPlayer.OnBufferingUpdateListener；
导入android.media.MediaPlayer.OnErrorListener；
导入android.media.MediaPlayer.OnPreparedListener；
导入android.os.AsyncTask；
导入android.os.IBinder；
导入android.util.Log；
导入android.widget.TextView；
公共类MyMediaPlayerService扩展了服务在PreparedListener、OnErrorListener和OnBufferingUpdateListener上的实现{
定时器；
TextView歌曲名；
字符串GetSongInfo；
MetadataTask metaTask=null；
私有媒体播放器MediaPlayer=null；
私有布尔isplay=false；
字符串url；
private static int classID=579；//只是一个数字
公共静态字符串START\u PLAY=“START\u PLAY”；
最终静态字符串MY_ACTION=“IcyData”；
@凌驾
公共IBinder onBind（意向）{
返回null；
}
@凌驾
公共int onStartCommand（Intent Intent、int标志、int startId）{
if（intent.getBooleanExtra（开始播放，false））{
url=intent.getStringExtra（“url”）；
play（）；
}
return Service.START\u STICKY；
}
私人虚空游戏（）{
如果（！isPlaying）{
isplay=true；
意向意向=新意向（此，StationListenActivity.class）；
intent.setFlags（intent.FLAG\u ACTIVITY\u REORDER\u TO\u FRONT）；
pendingent pi=pendingent.getActivity（this，0，intent，0）；
Notification Notification=new Notification.Builder（getApplicationContext（））
.setContentTitle（“社交广播”）
.setContentText（“正在播放：正在构建”）
.setSmallIcon（R.drawable.ic_启动器）
.setContentIntent（pi）
.build（）；
/*mediaPlayer=mediaPlayer.create（this，R.raw.rehab）；//为您的文件更改此项
mediaPlayer.setLooping（true）；//这将使它永远循环
mediaPlayer.start（）*/
//url=”http://ice.abradio.cz:80/hit90128.mp3“；//此处是您的URL
Log.i（“播放”，“播放：+url”）；
试一试{
mediaPlayer=新的mediaPlayer（）；
mediaPlayer.setAudioStreamType（AudioManager.STREAM_MUSIC）；
mediaPlayer.setVolume（100100）；
mediaPlayer.setDataSource（url）；
mediaPlayer.setOnPreparedListener（这个）；
mediaPlayer.prepareAsync（）；
mediaPlayer.setOneErrorListener（此）；
mediaPlayer.setOnBufferingUpdateListener（这个）；
}捕获（例外e）{
}
startForeground（classID，通知）；
}
}
@凌驾
公共空间{
Log.i（“破坏”、“停止”）；
停止（）；
//timer.cancel（）；
}   
私人停车场（）{
如果（显示）{
Log.i（“破坏”、“停止”）；
isplay=false；
如果（mediaPlayer！=null）{
mediaPlayer.release（）；
mediaPlayer=null；
}
停止前景（真）；
}
}
@凌驾
public void onBufferingUpdate（MediaPlayer arg0，int arg1）{
//TODO自动生成的方法存根
}
@凌驾
公共布尔onError（MediaPlayer arg0、int arg1、int arg2）{
//TODO自动生成的方法存根
返回false；
}
@凌驾
已准备好公开作废（MediaPlayer arg0）{
mediaPlayer.start（）；
StartTimer（）；
}
公共输入流OpenHttpPOSTConnection（字符串url）{
InputStream InputStream=null；
试一试{
HttpClient HttpClient=新的DefaultHttpClient（）；
HttpPost HttpPost=新的HttpPost（url）；
//---要发布到服务器的键/值对---
HttpResponse HttpResponse=httpclient.execute（httpPost）；
inputStream=httpResponse.getEntity（）.getContent（）；
}捕获（ConnectTimeoutException e）{
Log.d（“OpenHttpPostConnectionTimeout”，例如getLocalizedMessage（））；
}捕获（例外e）{
Log.d（“OpenHttpPOSTConnection”，e.getLocalizedMessage（））；
}
返回输入流；
}
公共无效StartTimer（）
{
试一试{
最终UR