无法从Android中的服务类启动活动（java.lang.NullPointerException）

时间：2012-01-12 12:11:00

标签： android

我有一个服务，用于解析xml数据（使用sax）之后我想要启动一个活动来显示使用intent解析的数据。但是每次我启动活动时我的服务都会崩溃，所以我删除了意图并改为举杯祝愿==＆gt;服务很好。但我真的需要从服务启动活动以使用xml rpc进行查询。我的小指告诉我它与上下文有关，但我对上下文一无所知。

这是我的服务:(问题在于intent1）

 package tfe.rma.ciss.be;

import java.io.IOException;
import java.io.StringReader;
import java.net.MalformedURLException;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;

public class ParseFunction  extends Service{
    Server monServer;
    public String streamTitle = "",path="";
    public void onCreate() {

        Log.d("ParseFunction", ">>>onCreate()");

    }

    @Override
    public void onStart (Intent intent, int startId) {
        Log.d("ParseFunction", ">>>Started()"); 
        if (!mydata.equals("")){
         try {

             // URL rssUrl = new URL("http://thibault-koprowski.fr/feed");
              SAXParserFactory mySAXParserFactory = SAXParserFactory.newInstance();
              SAXParser mySAXParser = mySAXParserFactory.newSAXParser();
              XMLReader myXMLReader = mySAXParser.getXMLReader();
              RSSHandler myRSSHandler = new RSSHandler();
              myXMLReader.setContentHandler(myRSSHandler);
              InputSource input = new InputSource(new StringReader(monServer.myData));
              myXMLReader.parse(input);
              Log.d("ParseFunction", ">>>my data is parsed()" + streamTitle );

             } catch (MalformedURLException e) {
                 Log.d("ParseFunction", ">>>exception()");  
              // TODO Auto-generated catch block
              e.printStackTrace();
              Log.d("ParseFunction", ">>>exception()");
             } catch (ParserConfigurationException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
              Log.d("ParseFunction", ">>>exception()");
             } catch (SAXException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
              Log.d("ParseFunction", ">>>exception()");
             } catch (IOException e) {
                 Log.d("ParseFunction", ">>>exception()");
              // TODO Auto-generated catch block
              e.printStackTrace();

             }
        }
        else {}
        if (!streamTitle.equals("")) {
            Log.d("ParseFunction", ">>>splitting streamTitle"); 
            try {
             String delims = "[\n]+" ;
                String[] tokens = streamTitle.split(delims) ;
                path= tokens[1];
                Log.d("ParseFunction", ">>>splitting done");

                Toast.makeText(this,path, Toast.LENGTH_SHORT).show();
                  }
            catch (Exception z) {
                Log.d("ParseFunction", ">>>splitting error" + " " + z); 

            }
        } else 
        { path="n'a pas pu parser" + "/n" + "no path found"; }

        try {

            Log.d("ParseFunction", ">>>lauching activity test but ...." );
        Intent intent1= new Intent (this, Test.class);
        intent1.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        intent1.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);



        startActivity(intent1); } catch (Exception z) {

            Log.d("ParseFunction", ">>>Activity said hell no, to screw myself " + z);

        }


    }
    private class RSSHandler extends DefaultHandler
      {
       final int stateUnknown = 0;
       final int stateTitle = 1;
       int state = stateUnknown;

       int numberOfTitle = 0;
       String strTitle = "";
       String strElement = "";

     @Override
     public void startDocument() throws SAXException {
      // TODO Auto-generated method stub

     }

     @Override
     public void endDocument() throws SAXException {
      // TODO Auto-generated method stub

      streamTitle =  strTitle;
     }

     @Override
     public void startElement(String uri, String localName, String qName,
       Attributes attributes) throws SAXException {
      // TODO Auto-generated method stub
      if (localName.equalsIgnoreCase("sensorType"))
      {
       state = stateTitle;
       strElement = "";
       numberOfTitle++;
      }
      else if (localName.equalsIgnoreCase("imagePath"))
      {
       state = stateTitle;
       strElement = "";
       numberOfTitle++;
      }
      else if (localName.equalsIgnoreCase("numThreats"))
      {
       state = stateTitle;
       strElement = "";
       numberOfTitle++;
      }

      else if (localName.equalsIgnoreCase("latitude"))
      {
       state = stateTitle;
       strElement = "";
       numberOfTitle++;
      }
      else if (localName.equalsIgnoreCase("longitude"))
      {
       state = stateTitle;
       strElement = "";
       numberOfTitle++;
      }
      else
      {
       state = stateUnknown;
      }
     }

     @Override
     public void endElement(String uri, String localName, String qName)
       throws SAXException {
      // TODO Auto-generated method stub
      if (localName.equalsIgnoreCase("sensorType"))
      {
       strTitle += strElement + "\n";
      }
      else if (localName.equalsIgnoreCase("imagePath"))
      {
       strTitle += strElement + "\n";
      }
      else if (localName.equalsIgnoreCase("numThreats"))
      {
       strTitle += strElement + "\n";
      }

      else if (localName.equalsIgnoreCase("latitude"))
      {
       strTitle += strElement + "\n";
      }
      else if (localName.equalsIgnoreCase("longitude"))
      {
       strTitle += strElement + "\n";
      }

      else {
      state = stateUnknown;}
     }

     @Override
     public void characters(char[] ch, int start, int length)
       throws SAXException {
      // TODO Auto-generated method stub
      String strCharacters = new String(ch, start, length);
      if (state == stateTitle)
      {
       strElement += strCharacters;
      }
     }

      }
    @Override
    public IBinder onBind(Intent arg0) {
        // TODO Auto-generated method stub
        return null;
    }
     public static String mydata = "<AvailableImageMsg><imageData><imageId>1234</imageId><sensorType>2</sensorType><imagePath>http://localhost/some/path</imagePath><timeStamp>2011-10-12T12:36:20</timeStamp></imageData><numThreats>3</numThreats><threatList><ThreadPixelDataType><threatData><threatId>3456</threatId><latitude>50.1234</latitude><longitude>4.5678</longitude><altitude>10.1</altitude><threatType>pepe</threatType><timestamp>2011-10-12T12:36:20</timestamp><threatLevel>70</threatLevel></threatData><Rectangle><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType></Rectangle></ThreadPixelDataType></threatList><threatList><ThreadPixelDataType><threatData><threatId>3457</threatId><latitude>50.1234</latitude><longitude>4.5678</longitude><altitude>10.1</altitude><threatType>pepe</threatType><timestamp>2011-10-12T12:36:20</timestamp><threatLevel>70</threatLevel></threatData><Rectangle><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType></Rectangle></ThreadPixelDataType></threatList><threatList><ThreadPixelDataType><threatData><threatId>3458</threatId><latitude>50.1234</latitude><longitude>4.5678</longitude><altitude>10.1</altitude><threatType>pepe</threatType><timestamp>2011-10-12T12:36:20</timestamp><threatLevel>70</threatLevel></threatData><Rectangle><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType><PixelCoordinatesType><x>100</x><y>200</y></PixelCoordinatesType></Rectangle></ThreadPixelDataType></threatList></AvailableImageMsg>";


}

以下是我的名为test

的简单活动 
package tfe.rma.ciss.be;


import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

public class Test extends Activity{

    ParseFunction parser; 

    @Override
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.test);

          TextView result = (TextView)findViewById(R.id.result);




          result.setText(parser.path);}



}

有人可以帮我吗?????！

Logcat报告 

01-12 13:42:18.069 I/ActivityManager(  160): Start proc tfe.rma.ciss.be for service tfe.rma.ciss.be/.ParseFunction: pid=1576 uid=10065 gids={3003, 1015}
01-12 13:42:18.189 D/ParseFunction( 1576): >>>onCreate()
01-12 13:42:18.189 D/ParseFunction( 1576): >>>Started()
01-12 13:42:18.189 D/AndroidRuntime( 1576): Shutting down VM
01-12 13:42:18.189 W/dalvikvm( 1576): threadid=1: thread exiting with uncaught exception (group=0x40018578)
01-12 13:42:18.199 E/        (  160): Dumpstate > /data/log/dumpstate_app_error
01-12 13:42:18.199 E/AndroidRuntime( 1576): FATAL EXCEPTION: main
01-12 13:42:18.199 E/AndroidRuntime( 1576): java.lang.RuntimeException: Unable to start service tfe.rma.ciss.be.ParseFunction@4051ecc8 with Intent { cmp=tfe.rma.ciss.be/.ParseFunction }: java.lang.NullPointerException
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2056)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at android.app.ActivityThread.access$2800(ActivityThread.java:117)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:998)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at android.os.Looper.loop(Looper.java:123)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at android.app.ActivityThread.main(ActivityThread.java:3687)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at java.lang.reflect.Method.invokeNative(Native Method)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at java.lang.reflect.Method.invoke(Method.java:507)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at dalvik.system.NativeStart.main(Native Method)
01-12 13:42:18.199 E/AndroidRuntime( 1576): Caused by: java.lang.NullPointerException
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at tfe.rma.ciss.be.ParseFunction.onStart(ParseFunction.java:45)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at android.app.Service.onStartCommand(Service.java:428)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2043)
01-12 13:42:18.199 E/AndroidRuntime( 1576):     ... 10 more
01-12 13:42:20.709 D/BatteryService(  160): update start
01-12 13:42:20.709 D/BatteryService(  160): update start
01-12 13:42:20.709 D/BatteryService(  160): update start
01-12 13:42:22.079 D/VoldCmdListener(   87): asec list
01-12 13:42:22.089 D/VoldCmdListener(   87): CommandListener::AsecCmd::runCommand -> com.aldiko.android-1
01-12 13:42:22.089 D/VoldCmdListener(   87): CommandListener::AsecCmd::runCommand -> com.citc.ud-1
01-12 13:42:22.089 D/VoldCmdListener(   87): CommandListener::AsecCmd::runCommand -> com.creativemobile.DragRacing-1

3 个答案:

答案 0 :(得分：0)

Intent intent1= new Intent (this, Test.class);
intent1.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);

在最后一行中，您指的是intent而不是intent1。您是否在某处未初始化了另一个名为intent的字段？

答案 1 :(得分：0)

而不是

Intent intent1= new Intent (this, Test.class);

尝试：

Intent intent1= new Intent (getApplicationContext(), Test.class);

如果这不起作用，请尝试不添加标记。

但是，请记住，您不应该从服务启动活动或与UI交互。

答案 2 :(得分：0)

//此处您的内容为空

Intent intent1= new Intent (this, Test.class);

在此处传递您的申请上下文

Intent intent1= new Intent (mContent, Test.class);
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