我遇到了一个问题，即我遇到空指针异常(并强制关闭(的问题：
nameArr = handler.getnameArr();
。在 ConfigFinalActivity 中(如下所示(。我尝试调试不同的值
ConfigFinalActivity 源代码片段：
public class ConfigFinalActivity extends Activity implements OnClickListener {
private static final String TAG = "ConfigActivity";
TelephonyManager tm;
AlertDialog mErrorAlert = null;
private Notification mNotification = null;
private Button mXButton = null;
private Button mAssistUpdateButton = null;
private Button mAssistInstrButton = null;
private Button mReadAgainButton = null;
private int mInstructionNumber = 0;
public static ArrayList<String> NameArr = new ArrayList<String>();
public static ArrayList<String> ValueArr = new ArrayList<String>();
public static ArrayList<String> nameArr = new ArrayList<String>();
public static ArrayList<String> ApnArr = new ArrayList<String>();
public static ArrayList<String> mmscArr = new ArrayList<String>();
public static ArrayList<String> mmsportArr = new ArrayList<String>();
public static ArrayList<String> mmsproxyArr = new ArrayList<String>();
public static ArrayList<String> portArr = new ArrayList<String>();
public static ArrayList<String> proxyArr = new ArrayList<String>();
public static int count;
public static int TotalSteps = 8;
int i, g = 0, result = 0;
public static ContentValues Values = new ContentValues();
XmlParserHandlerFinal handler;
public static final Uri APN_TABLE_URI = Uri
.parse("content://telephony/carriers");
public static final String Base_URL = "https://test.testsite555.com/REST/phoneSettings";
public static InputStream stream = null;
UpdateActivity update;
public static String status, queryResult = "";
/** Called when the activity is first created. */
@SuppressLint("NewApi")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
int version = android.os.Build.VERSION.SDK_INT;
tm = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);
update = new UpdateActivity();
getArrayLists();
/*
* boolean deleted = deleteFile("settings.xml");if(deleted){
* Log.v("settings.xml","deleted"); }else
* Log.v("settings.xml","failed to delete the file");
*/
if (ApnArr.isEmpty() || mmscArr.isEmpty()) {
// tryagain();
} else if (version < VERSION_CODES.ICE_CREAM_SANDWICH) {
// Update APN table
try {
result = updateTable();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}// Settings updated with this atomic call
catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (result != -1) {
status = "success";
} else {
status = "failure";
}
if (status.equals("success")) {
completeUpdate();
} else if (status.equals("failure")) {
// tryagain();
// showAlert(getString(R.string.unchanged_dialog));
}
} else {// ICS and later versions
// Reduce number of steps to 6
TotalSteps = 6;
setContentView(R.layout.assist_instructions);
String assistUpdate = getString(R.string.instructions_1);
CharSequence styledText = Html.fromHtml(assistUpdate);
TextView assistText = (TextView) findViewById(R.id.apn_app_text_cta2);
assistText.setText(styledText);
mAssistUpdateButton = (Button) findViewById(R.id.assist_update_btn);
mAssistUpdateButton.setOnClickListener(this);
}
}
private void getArrayLists() {
nameArr = handler.getnameArr();
ApnArr = handler.getApnArr();
mmscArr = handler.getMMSCArr();
mmsproxyArr = handler.getMmscProxyArr();
mmsportArr = handler.getMmsPortArr();
proxyArr = handler.getProxyArr();
portArr = handler.getPortArr();
count = handler.getCount();
result = handler.getResult();
}
我知道应用程序由于上面显示的代码中的空值而崩溃 - 但我需要一些帮助来确定可能导致它为空的原因。
我相信问题源于以下活动中的问题(但目前我不确定 - 任何调试/断点建议都会非常棘手(：
更新活动：
public class UpdateActivity extends Activity {
private TelephonyManager tm;
AlertDialog mConfirmAlert = null;
NetworkTask task;
ImageView image, text;
AlertDialog mErrorAlert = null;
public static ArrayList<String> NameArr = new ArrayList<String>();
public static ArrayList<String> ValueArr = new ArrayList<String>();
public static ArrayList<String> nameArr = new ArrayList<String>();
public static ArrayList<String> ApnArr = new ArrayList<String>();
public static ArrayList<String> mmscArr = new ArrayList<String>();
public static ArrayList<String> mmsportArr = new ArrayList<String>();
public static ArrayList<String> mmsproxyArr = new ArrayList<String>();
public static ArrayList<String> portArr = new ArrayList<String>();
public static ArrayList<String> proxyArr = new ArrayList<String>();
public static int count;
public AnimationDrawable mTextAnimation = null;
TextView mUpdatetext;
public static InputStream stream = null;
int version;
public static BigInteger iD1, iD2, mdN1, mdN2;
BigInteger[] id, mdnId;
public static String ICCID, MDN;
public static String caR;
public static int result;
private static final String LOG_TAG = "DataSettings";
public static final String Base_URL = "https://someurl.testsite555.com/REST/phoneSettings";
public static XmlParserHandlerFinal handler;
public static int TotalSteps = 8;
public FileInputStream fis;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// instance for xml parser class
handler = new XmlParserHandlerFinal();
handler.setContext(this.getBaseContext());
tm = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);
int networkType = tm.getNetworkType();
int phoneType = tm.getPhoneType();
version = android.os.Build.VERSION.SDK_INT;
// to get MDN(MCC+MNC) of the provider of the SIM and ICCID (Serial
// number of the SIM)
// and to check for the Carrier type
getImpVariablesForQuery();
task = new NetworkTask();
if (phoneType == TelephonyManager.PHONE_TYPE_CDMA
|| (phoneType != TelephonyManager.PHONE_TYPE_GSM
&& networkType != TelephonyManager.NETWORK_TYPE_GPRS
&& networkType != TelephonyManager.NETWORK_TYPE_EDGE
&& networkType != TelephonyManager.NETWORK_TYPE_HSDPA
&& networkType != TelephonyManager.NETWORK_TYPE_HSPA
&& networkType != TelephonyManager.NETWORK_TYPE_HSPAP
&& networkType != TelephonyManager.NETWORK_TYPE_HSUPA
&& networkType != TelephonyManager.NETWORK_TYPE_UMTS && networkType != TelephonyManager.NETWORK_TYPE_LTE)) {
// If the phone type is CDMA or
// the phone phone type is not GSM and the network type is none of
// the network types indicated in the statement
// Display incompatibility message
showAlert(getString(R.string.incomp_sm_dialog));
// Network type is looked because some tablets have no phone type.
// We rely on network type in such cases
} else if (!(tm.getSimState() == TelephonyManager.SIM_STATE_ABSENT
|| (tm.getSimOperator())
.equals(getString(R.string.numeric_tmo)) || (tm
.getSimOperator()).equals(getString(R.string.numeric_att)))) {
// if SIM is present and is NOT a T-Mo or ATT network SIM,
// display Error message alert indicating to use SM SIM
showAlert(getString(R.string.insert_sm_dialog));
}// No SIM or SIM with T-Mo & ATT MNC MCC present
else if ((tm.getSimOperator()).equals(getString(R.string.numeric_tmo))
|| (tm.getSimOperator())
.equals(getString(R.string.numeric_att))) {
// Device has T-Mo or ATT network SIM card MCC and MNC correctly
// populated
TotalSteps = 6;
setContentView(R.layout.updating);
// image = (ImageView) findViewById(R.id.updating_image);
// text = (ImageView) findViewById(R.id.updating_text);
//
// text.setBackgroundResource(R.drawable.animation);
// mTextAnimation = (AnimationDrawable) text.getBackground();
// AsyncTask to call the web service
task.execute("");
}
}
// @Override
// public void onWindowFocusChanged(boolean hasFocus) {
// super.onWindowFocusChanged(hasFocus);
// // Animate GO button when corresponding window is in focus
// Animation a = AnimationUtils.loadAnimation(getBaseContext(),
// R.anim.image);
// a.setDuration(1000);
// a.setInterpolator(new Interpolator() {
// private final int frameCount = 16;
//
// @Override
// public float getInterpolation(float input) {
// return (float) Math.floor(input * frameCount) / frameCount;
// }
// });
// image.startAnimation(a);
//
// mTextAnimation.start();
// }
private void getImpVariablesForQuery() {
long d = 1234;
BigInteger divisor = BigInteger.valueOf(d);
// to get MDN
MDN = tm.getLine1Number();
// MDN = "7862125102";
if (MDN.equals("")) {
mdN1 = null;
mdN2 = null;
} else {
Log.d("MDN", MDN);
BigInteger bInt = new BigInteger(MDN);
mdnId = bInt.divideAndRemainder(divisor);
// to retrieve ICCID number of the SIM
mdN1 = mdnId[1];
System.out.println("MDN%1234 = " + mdN1);
mdN2 = mdnId[0];
System.out.println("MDN/1234 = " + mdN2);
}
ICCID = tm.getSimSerialNumber();
if (ICCID.equals("")) {
iD1 = null;
iD2 = null;
} else {
Log.d("ICCID", ICCID);
BigInteger bInteger = new BigInteger(ICCID);
id = bInteger.divideAndRemainder(divisor);
iD1 = id[1];
System.out.println("ICCID%1234 = " + iD1);
iD2 = id[0];
System.out.println("ICCID/1234 = " + iD2);
}
// Check for the Carrier Type
if ((tm.getSimOperator()).equals(getString(R.string.numeric_tmo))) {
caR = "TMO";
} else if ((tm.getSimOperator())
.equals(getString(R.string.numeric_att))) {
caR = "ATT";
}
}
// method to save the ArrayLists from parser
public static void setArrayList() {
nameArr = handler.getnameArr();
ApnArr = handler.getApnArr();
mmscArr = handler.getMMSCArr();
mmsproxyArr = handler.getMmscProxyArr();
mmsportArr = handler.getMmsPortArr();
proxyArr = handler.getProxyArr();
portArr = handler.getPortArr();
count = handler.getCount();
result = handler.getResult();
}
private void showAlert(String message) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage(message).setPositiveButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
UpdateActivity.this.finish();
}
});
mConfirmAlert = builder.create();
mConfirmAlert.show();
}
public ArrayList<String> getnameArr() {
return nameArr;
}
public ArrayList<String> getApnArr() {
return ApnArr;
}
public ArrayList<String> getMMSCArr() {
return mmscArr;
}
public ArrayList<String> getMmscProxyArr() {
return mmsproxyArr;
}
public ArrayList<String> getMmsPortArr() {
return mmsportArr;
}
public int getCount() {
return count;
}
public ArrayList<String> getProxyArr() {
return proxyArr;
}
public ArrayList<String> getPortArr() {
return portArr;
}
// AsyncTask to call web service
private class NetworkTask extends AsyncTask<String, Integer, InputStream> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected InputStream doInBackground(String... params) {
try {
/*
* query the server for the data settings put the returned data
* settings into values
*/
// String charset = "UTF-8";
// String param1 = "mdn1=";
// String param2 = "&mdn2=";
// String param3 = "&car=";
// String param4 = "&id1=";
// String param5 = "&id2=";
// String parameters = param1 + Mdn1 + param2 + Mdn2 + param3
// + Car + param4 + iD1 + param5 + iD2;
// String parameters = param1 + Mdn1 + param2 + Mdn2 ;
// URL = Base_URL + URLEncoder.encode(parameters, charset);
Log.i("url...", Base_URL);
stream = getQueryResults(Base_URL);
} catch (IOException e) {
Log.v(LOG_TAG, e.toString());
e.printStackTrace();
} catch (SAXException e) {
Log.v(LOG_TAG, e.toString());
e.printStackTrace();
} catch (Exception e) {
Log.v(LOG_TAG, e.toString());
e.printStackTrace();
}
return stream;
}
/*
* Sends a query to server and gets back the parsed results in a bundle
* urlQueryString - URL for calling the webservice
*/
protected synchronized InputStream getQueryResults(String urlQueryString)
throws IOException, SAXException, SSLException,
SocketTimeoutException, Exception {
// HttpsURLConnection https = null;
try {
// HttpsURLConnection https = null;
String uri = urlQueryString;
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
// BasicNameValuePair username = new
// BasicNameValuePair("username",
// "nmundru");
// BasicNameValuePair password = new
// BasicNameValuePair("password",
// "abc123");
BasicNameValuePair mdn1, mdn2,id1,id2;
if (MDN.equals("")) {
mdn1 = new BasicNameValuePair("mdn1", null);
mdn2 = new BasicNameValuePair("mdn2", null);
} else {
mdn1 = new BasicNameValuePair("mdn1", mdN1.toString());
mdn2 = new BasicNameValuePair("mdn2", mdN2.toString());
}
BasicNameValuePair car = new BasicNameValuePair("car", caR);
if (ICCID.equals("")) {
id1 = new BasicNameValuePair("id1", null);
id2 = new BasicNameValuePair("id2", null);
} else {
id1 = new BasicNameValuePair("id1",
iD1.toString());
id2 = new BasicNameValuePair("id2",
iD2.toString());
}
// nameValuePairs.add(username);
// nameValuePairs.add(password);
nameValuePairs.add(mdn1);
nameValuePairs.add(mdn2);
nameValuePairs.add(car);
nameValuePairs.add(id1);
nameValuePairs.add(id2);
UrlEncodedFormEntity urlEncodedFormEntity = new UrlEncodedFormEntity(
nameValuePairs, "ISO-8859-1");
KeyStore trustStore = KeyStore.getInstance(KeyStore
.getDefaultType());
trustStore.load(null, null);
SSLSocketFactory sf = new MySSLSocketFactory(trustStore);
sf.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
HttpParams params = new BasicHttpParams();
HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);
SchemeRegistry registry = new SchemeRegistry();
registry.register(new Scheme("http", PlainSocketFactory
.getSocketFactory(), 80));
registry.register(new Scheme("https", sf, 443));
ClientConnectionManager ccm = new ThreadSafeClientConnManager(
params, registry);
HttpClient httpClient = new DefaultHttpClient(ccm, params);
params = httpClient.getParams();
HttpClientParams.setRedirecting(params, true);
HttpPost httpPost = new HttpPost(uri);
httpPost.addHeader("Authorization",
getB64Auth("nmundru", "abc123"));
httpPost.setHeader("Content-Type", "text/plain; charset=utf-8");
Log.v("httpPost", httpPost.toString());
httpPost.setEntity(urlEncodedFormEntity);
HttpResponse httpResponse = httpClient.execute(httpPost);
System.out.println("response...." + httpResponse.toString());
Log.v("response...", httpResponse.toString());
stream = httpResponse.getEntity().getContent();
// save the InputStream in a file
try {
FileOutputStream fOut = openFileOutput("settings.xml",
Context.MODE_WORLD_READABLE);
DataInputStream in = new DataInputStream(stream);
BufferedReader br = new BufferedReader(
new InputStreamReader(in));
String strLine;
while ((strLine = br.readLine()) != null) {
System.out.println(strLine); //to print the response
// in logcat
fOut.write(strLine.getBytes());
}
fOut.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
fis = openFileInput("settings.xml");
} catch (Exception e) {
Log.e(LOG_TAG, e.toString());
// e.printStackTrace();
tryagain();
} finally {
// https.disconnect();
}
return stream;
}
private String getB64Auth(String login, String pass) {
String source = login + ":" + pass;
String ret = "Basic "
+ Base64.encodeToString(source.getBytes(), Base64.URL_SAFE
| Base64.NO_WRAP);
return ret;
}
@Override
protected void onProgressUpdate(Integer... progress) {
}
@Override
protected void onPostExecute(InputStream stream) {
super.onPostExecute(stream);
// This method is called to parse the response and save the
// ArrayLists
success();
}
}
@Override
protected void onRestart() {
super.onRestart();
if (mErrorAlert != null)
mErrorAlert.dismiss();
}
public void tryagain() {
// Displaying final layout after failure of pre-ICS automatic settings
// update
// setContentView(R.layout.tryagain);
// String tryAgainText = "";
// CharSequence styledTryAgainText;
//
// tryAgainText = String.format(getString(R.string.tryagain_text1),
// TotalSteps);
// styledTryAgainText = Html.fromHtml(tryAgainText);
// TextView tryAgain1 = (TextView) findViewById(R.id.tryagain_text1);
// tryAgain1.setText(styledTryAgainText);
//
// tryAgainText = String.format(getString(R.string.tryagain_text2),
// TotalSteps);
// styledTryAgainText = Html.fromHtml(tryAgainText);
// TextView tryAgain2 = (TextView) findViewById(R.id.tryagain_text2);
// tryAgain2.setText(styledTryAgainText);
//
// tryAgainText = String.format(getString(R.string.tryagain_text3),
// TotalSteps);
// styledTryAgainText = Html.fromHtml(tryAgainText);
// TextView tryAgain3 = (TextView) findViewById(R.id.tryagain_text3);
// tryAgain3.setText(styledTryAgainText);
}
public void success() {
// to parse the response
try {
handler.getQueryResponse(fis);
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// set method to save the ArryaLists from the parser
setArrayList();
Intent i = new Intent(this, ConfigFinalActivity.class);
startActivity(i);
finish();
}
public int getResult() {
return result;
}
}
如果你确定这一行
nameArr = handler.getnameArr();
给出NPE然后你知道问题一定是此时handler null。这是这条线抛出NPE的唯一方式.从查看大量代码来看，在调用使用它的方法之前handler看起来肯定没有实例化(getArrayLists();(。你在这里声明
XmlParserHandlerFinal handler;
但是在尝试使用它之前，您永远不会给它一个值。
您需要在此Activity中实例化它，然后才能对其调用方法，例如 getnameArr(); 。您在其他Activity中实例化它，但在此中不实例化。