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连接到 Web 服务时，我的 Android 客户端出现 NullPointerException。我真的不知道为什么...

日志猫：

01-12 18:46:55.062: E/AndroidRuntime(831): FATAL EXCEPTION: main
01-12 18:46:55.062: E/AndroidRuntime(831): java.lang.RuntimeException: Unable to start activity ComponentInfo{pl.webcentral.androidclient1/pl.webcentral.androidclient1.MainActivity}: java.lang.NullPointerException
01-12 18:46:55.062: E/AndroidRuntime(831):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
01-12 18:46:55.062: E/AndroidRuntime(831):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
01-12 18:46:55.062: E/AndroidRuntime(831):  at android.app.ActivityThread.access$600(ActivityThread.java:130)
01-12 18:46:55.062: E/AndroidRuntime(831):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
01-12 18:46:55.062: E/AndroidRuntime(831):  at android.os.Handler.dispatchMessage(Handler.java:99)
01-12 18:46:55.062: E/AndroidRuntime(831):  at android.os.Looper.loop(Looper.java:137)
01-12 18:46:55.062: E/AndroidRuntime(831):  at android.app.ActivityThread.main(ActivityThread.java:4745)
01-12 18:46:55.062: E/AndroidRuntime(831):  at java.lang.reflect.Method.invokeNative(Native Method)
01-12 18:46:55.062: E/AndroidRuntime(831):  at java.lang.reflect.Method.invoke(Method.java:511)
01-12 18:46:55.062: E/AndroidRuntime(831):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
01-12 18:46:55.062: E/AndroidRuntime(831):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
01-12 18:46:55.062: E/AndroidRuntime(831):  at dalvik.system.NativeStart.main(Native Method)
01-12 18:46:55.062: E/AndroidRuntime(831): Caused by: java.lang.NullPointerException
01-12 18:46:55.062: E/AndroidRuntime(831):  at pl.webcentral.androidclient1.GameAndroidUtil.callGameStatus(GameAndroidUtil.java:106)
01-12 18:46:55.062: E/AndroidRuntime(831):  at pl.webcentral.androidclient1.GameAndroidUtil.testGameWS(GameAndroidUtil.java:21)
01-12 18:46:55.062: E/AndroidRuntime(831):  at pl.webcentral.androidclient1.MainActivity.onCreate(MainActivity.java:24)
01-12 18:46:55.062: E/AndroidRuntime(831):  at android.app.Activity.performCreate(Activity.java:5008)
01-12 18:46:55.062: E/AndroidRuntime(831):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
01-12 18:46:55.062: E/AndroidRuntime(831):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
01-12 18:46:55.062: E/AndroidRuntime(831):  ... 11 more

GameAndroidUtil:

package pl.webcentral.androidclient1;

import org.ksoap2.SoapEnvelope;
import org.ksoap2.SoapFault;
import org.ksoap2.serialization.PropertyInfo;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapPrimitive;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;

public class GameAndroidUtil {
    private static final String NAMESPACE = "http://game.webcentral.pl/";
    private static final String SOAP_ACTION = "";
    private static final String WSDL_URL = "http://10.0.2.2:8080/ReversiGameWS/services/GameWS?wsdl";

    public static void testGameWS() throws SoapFault {

        String session1 = callGameLogin("Marcin 1");


        GameStatus gameStatus = callGameStatus(session1);
        System.out.println("Status gracza 1 " + gameStatus.getLastMove() + " " + gameStatus.isYourMove());


        String session2 = callGameLogin("Marcin 2");


        gameStatus = callGameStatus(session2);
        System.out.println("Status gracza 2 " + gameStatus.getLastMove() + " " + gameStatus.isYourMove());

        gameStatus = callGameStatus(session1);
        System.out.println("Status gracza 1 " + gameStatus.getLastMove() + " " + gameStatus.isYourMove());


        try {
            callGameAddMove(session1, 5);
        } catch (Exception e) {
            System.out.println("Złapaliśmy wyjątek zgodnie z założeniem");
        }


        callGameAddMove(session2, 5);


        gameStatus = callGameStatus(session2);
        System.out.println("Status gracza 1 " + gameStatus.getLastMove() + " " + gameStatus.isYourMove());

        gameStatus = callGameStatus(session1);
        System.out.println("Status gracza 2 " + gameStatus.getLastMove() + " " + gameStatus.isYourMove());
    }

    private static String callGameLogin(String userName) {
        String METHOD_NAME = "login";

        SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME); 
        SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); 

        PropertyInfo propInfo=new PropertyInfo();
        propInfo.setName("arg0");
        propInfo.setType(PropertyInfo.STRING_CLASS);
        propInfo.setValue(userName);

        request.addProperty(propInfo);

        envelope.setOutputSoapObject(request);
        HttpTransportSE androidHttpTransport = new HttpTransportSE(WSDL_URL);

        try {
            androidHttpTransport.call(SOAP_ACTION, envelope);

            SoapPrimitive resultsRequestSOAP = (SoapPrimitive) envelope.getResponse();

            return resultsRequestSOAP.toString();

        } catch (Exception e) {
            throw new RuntimeException("Unexpected exception", e);
        }
    }
    private static GameStatus callGameStatus(String sessionId) throws SoapFault {
        String METHOD_NAME = "getGameStatus";

        SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME); 
        SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); 

        PropertyInfo propInfo=new PropertyInfo();
        propInfo.setName("arg0");
        propInfo.setType(PropertyInfo.STRING_CLASS);
        propInfo.setValue(sessionId);

        request.addProperty(propInfo);

        envelope.setOutputSoapObject(request);
        HttpTransportSE androidHttpTransport = new HttpTransportSE(WSDL_URL);

        try {
            androidHttpTransport.call(SOAP_ACTION, envelope);
        } catch (Exception e) {
            throw new RuntimeException("Unexpected exception", e);
        }

        try {
            SoapObject response = (SoapObject)envelope.getResponse();

            GameStatus gameStatus = new GameStatus();
            if (response.hasProperty("lastMove")) {
                gameStatus.setLastMove(Integer.parseInt(response.getProperty("lastMove").toString()));
            }
            gameStatus.setYourMove(Boolean.parseBoolean(response.getProperty("yourMove").toString()));

            return gameStatus;
        } catch (SoapFault e) {
            System.out.println("Error adding move: " + e.faultstring);//można to ładnie jakoś pokazać na ekranie
            throw e;
        }

    }
    private static void callGameAddMove(String sessionId, Integer move) throws SoapFault {
        String METHOD_NAME = "addMove";

        SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME); 
        SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); 

        PropertyInfo propInfo=new PropertyInfo();
        propInfo.setName("arg0");
        propInfo.setType(PropertyInfo.STRING_CLASS);
        propInfo.setValue(sessionId);

        request.addProperty(propInfo);

        propInfo=new PropertyInfo();
        propInfo.setName("arg1");
        propInfo.setType(PropertyInfo.INTEGER_CLASS);
        propInfo.setValue(move);

        request.addProperty(propInfo);

        envelope.setOutputSoapObject(request);
        HttpTransportSE androidHttpTransport = new HttpTransportSE(WSDL_URL);

        try {
            androidHttpTransport.call(SOAP_ACTION, envelope);
        } catch (Exception e) {
            throw new RuntimeException("Unexpected exception", e);
        }

        try {
            SoapPrimitive resultsRequestSOAP = (SoapPrimitive) envelope.getResponse();
        } catch (SoapFault e) {
            System.out.println("Error adding move: " + e.faultstring);//można to ładnie jakoś pokazać na ekranie
            throw e;
        }
    }

}

问题就在这里：

            gameStatus.setLastMove(Integer.parseInt(response.getProperty("lastMove").toString());

为什么会这样？仅当响应具有此属性时才执行此行。如果有，为什么是 NullPointer？

4

2 回答 2

0 
            gameStatus.setLastMove(Integer.parseInt(response.getProperty("lastMove").toString()));

The below line is null, thats why null pointer exception, pls add log n check it out
response.getProperty("lastMove").toString()

于 2013-01-12T18:15:32.320 回答
0

似乎 Log.d("lastMove", response.getProperty("lastMove").toString()); 现在正在导致 NullPointerException ...

很明显，这response.getProperty("lastMove")就是问题所在。这意味着它response有一个键，"lastMove"但值本身是null......只需使用：

if (response.hasProperty("lastMove") && response.getProperty("lastMove") != null) {
    gameStatus.setLastMove(Integer.parseInt(response.getProperty("lastMove").toString()));
}

（如果您控制 SOAPObject 的创建方式，您应该首先找出为什么要保存空值。）

于 2013-01-12T19:51:57.680 回答