连接到Webservice时，我的Android客户端出现NullPointerException。我真的不知道为什么......
logcat的：
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;
}
}
}
问题在于：
gameStatus.setLastMove(Integer.parseInt(response.getProperty("lastMove").toString());
为什么会这样？仅当response具有此属性时才会执行此行。如果有，为什么NullPointer？
答案 0 :(得分：0)
gameStatus.setLastMove(Integer.parseInt(response.getProperty("lastMove").toString()));
以下行为空，这就是为什么空指针异常，请添加log n检查出来 response.getProperty（ “lastMove”）。的toString（）
答案 1 :(得分：0)
似乎是Log.d（“lastMove”，response.getProperty（“lastMove”）。toString（））;现在导致NullPointerException ...
显然response.getProperty("lastMove")是问题所在。这意味着response有"lastMove"的密钥，但值本身为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，您应该首先找出保存空值的原因。）