我无法找出导致错误的行。我知道它是 NullPointerException，但我找不到确切的原因。
11-09 20:04:57.677: ERROR/AndroidRuntime(22119): FATAL EXCEPTION: main
java.lang.NullPointerException
at android.app.Activity.findViewById(Activity.java:1853)
at com.example.Posten2.HenteFelt.samleStatuser(HenteFelt.java:128)
at com.example.Posten2.Posten.finnInfo(Posten.java:109)
at com.example.Posten2.Posten.string(Posten.java:72)
at com.example.Posten2.Posten$GetData.onPostExecute(Posten.java:190)
at com.example.Posten2.Posten$GetData.onPostExecute(Posten.java:160)
at android.os.AsyncTask.finish(AsyncTask.java:631)
at android.os.AsyncTask.access$600(AsyncTask.java:177)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
在文档中，我发现应该有一行以“原因：”开头，这是错误真正发生的地方。
HenteFelt.java 的代码
public class HenteFelt extends Activity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
String returnString;
public String avsenderLand(JSONObject object) {
//Sjekker avsenderland fra json - retureneren en string
try {
JSONArray consignmentSet = object.getJSONArray("consignmentSet");
JSONObject object1 = consignmentSet.getJSONObject(0);
JSONArray packageSet = object1.getJSONArray("packageSet");
JSONObject object2 = packageSet.getJSONObject(0);
JSONArray eventSet = object2.getJSONArray("eventSet");
Integer countEvents = eventSet.length();
countEvents = countEvents - 1;
JSONObject object3 = eventSet.getJSONObject(countEvents);
String country = object3.getString("country");
returnString = "Pakken er sendt fra : " + country + "\n";
} catch (JSONException e) {
e.printStackTrace();
}
return returnString;
}
public String lesSisteStatus(JSONObject object) {
//leser ut siste status fra json - retureneren en string
String ID = "";
try {
JSONArray consignmentSet = object.getJSONArray("consignmentSet");
JSONObject object1 = consignmentSet.getJSONObject(0);
JSONArray packageSet = object1.getJSONArray("packageSet");
JSONObject object2 = packageSet.getJSONObject(0); //object inni packageSet
JSONArray eventSet = object2.getJSONArray("eventSet");
JSONObject object3 = eventSet.getJSONObject(0);
ID = "Siste status er : " + object3.getString("description") + "\n";
if (ID.contentEquals("Siste status er : Sendingen er utlevert\n")) {
ID = "Du har hentet pakken !";
}
} catch (Exception ex) {
Toast.makeText(getApplicationContext(), "Vennligst bruk et gyldig sporingsnummer", Toast.LENGTH_SHORT).show();
}
return ID;
}
public String sentDato(JSONObject object) {
try {
JSONArray consignmentSet = object.getJSONArray("consignmentSet");
JSONObject object1 = consignmentSet.getJSONObject(0);
JSONArray packageSet = object1.getJSONArray("packageSet");
JSONObject object2 = packageSet.getJSONObject(0);
JSONArray eventSet = object2.getJSONArray("eventSet");
Integer countEvents = eventSet.length();
countEvents = countEvents - 1;
JSONObject object3 = eventSet.getJSONObject(countEvents);
object3.getString("displayDate");
returnString = "Datoen varen ble sendt er : " + object3.getString("displayDate") + "\n";
} catch (Exception e) {
e.printStackTrace();
}
return returnString;
}
public String antallEventer(JSONObject object) {
try {
//Sjekker antall hendelser i json - retureneren en string
JSONArray consignmentSet = object.getJSONArray("consignmentSet");
JSONObject object1 = consignmentSet.getJSONObject(0);
JSONArray packageSet = object1.getJSONArray("packageSet");
JSONObject object2 = packageSet.getJSONObject(0);
JSONArray eventSet = object2.getJSONArray("eventSet");
Integer countEvents = eventSet.length();
returnString = "Antall hendelser er : " + countEvents.toString() + "\n";
} catch (JSONException e) {
e.printStackTrace();
}
return returnString;
}
public String samleStatuser(JSONObject object) {
//TODO lage en string array som inneholder de ulike statusene pakken har hatt samt dato og tid på de.
Integer countEvents = 0;
String buffer = "";
String dato = "";
String tid = "";
ArrayList<String> arrayList = new ArrayList<String>();
ListView lv = (ListView) findViewById(R.id.listView);
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, arrayList);
try {
JSONArray consignmentSet = object.getJSONArray("consignmentSet");
JSONObject object1 = consignmentSet.getJSONObject(0);
JSONArray packageSet = object1.getJSONArray("packageSet");
JSONObject object2 = packageSet.getJSONObject(0);
JSONArray eventSet = object2.getJSONArray("eventSet");
countEvents = eventSet.length();
} catch (Exception e) {
e.printStackTrace();
}
Integer i;
Integer objekt;
if (countEvents == 0) {
i = 0;
try {
JSONArray consignmentSet = object.getJSONArray("consignmentSet");
JSONObject object1 = consignmentSet.getJSONObject(0);
JSONArray packageSet = object1.getJSONArray("packageSet");
JSONObject object2 = packageSet.getJSONObject(0);
JSONArray eventSet = object2.getJSONArray("eventSet");
JSONObject object3 = eventSet.getJSONObject(i);
buffer = object3.getString("description");
dato = object3.getString("displayTime");
tid = object3.getString("displayDate");
returnString += dato + "kl : " + tid + " Status : " + buffer;
} catch (Exception e) {
e.printStackTrace();
}
}
for (i = countEvents; i > 0; i--) {
try {
objekt = i - 1;
JSONArray consignmentSet = object.getJSONArray("consignmentSet");
JSONObject object1 = consignmentSet.getJSONObject(0);
JSONArray packageSet = object1.getJSONArray("packageSet");
JSONObject object2 = packageSet.getJSONObject(0);
JSONArray eventSet = object2.getJSONArray("eventSet");
JSONObject object3 = eventSet.getJSONObject(objekt);
buffer = object3.getString("description");
dato = object3.getString("displayTime");
tid = object3.getString("displayDate");
returnString += dato + "kl : " + tid + " Status : " + buffer + "\n";
lagArrayList(returnString, arrayList, arrayAdapter, lv);
} catch (Exception e) {
e.printStackTrace();
}
}
{
}
return returnString;
}
public void lagArrayList(String status, ArrayList<String> arrayList, ArrayAdapter<String> arrayAdapter, ListView lv) {
try {
arrayList.add(status);
String s = status += "YYY";
// ListView lv = (ListView) findViewById(R.id.listView);
lv.setAdapter(arrayAdapter);
} catch (Exception e) {
e.printStackTrace();
}
}
public String hentetDatoTid(JSONObject object) {
try {
JSONArray consignmentSet = object.getJSONArray("consignmentSet");
JSONObject object1 = consignmentSet.getJSONObject(0);
JSONArray packageSet = object1.getJSONArray("packageSet");
JSONObject object2 = packageSet.getJSONObject(0);
JSONArray eventSet = object2.getJSONArray("eventSet");
JSONObject object3 = eventSet.getJSONObject(0);
String dato = object3.getString("displayDate");
String tid = object3.getString("displayTime");
String sted = object3.getString("city");
returnString = "Klokka : " + tid + " " + "\n" + "Den " + dato + " " + "\n" + "På " + sted;
} catch (JSONException e) {
e.printStackTrace();
}
return returnString;
}
}
“Posten.java”的代码
public class Posten extends Activity {
/**
* Called when the activity is first created.
*/
EditText et_sporingsnummer = null;
String ID = "";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button = (Button) findViewById(R.id.button);
et_sporingsnummer = (EditText) findViewById(R.id.editText);
et_sporingsnummer.setText("TESTPACKAGE-LOADED-FOR-DELIVERY");
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String[] input = {String.valueOf(et_sporingsnummer.getText())};
new GetData().execute(input);
}
});
}
public void string(String sporingsnummer, String json) {
FileOutputStream oFile;
String sFileName = sporingsnummer + ".json";
try {
oFile = openFileOutput(sFileName, Context.MODE_PRIVATE);
oFile.write(json.getBytes());
oFile.close();
} catch (Exception ex) {
//handle exception here
}
finnInfo(sporingsnummer);
}
public void finnInfo(String sporingsnummer) {
InputStream oFile;
String combine;
try {
TextView tv = (TextView) findViewById(R.id.txt_sendtDato);
oFile = openFileInput(sporingsnummer + ".json");
InputStreamReader oReader = new InputStreamReader(oFile);
BufferedReader oBuffer = new BufferedReader(oReader);
String sText = "";
String sEachLine = "";
while ((sEachLine = oBuffer.readLine()) != null) {
sText += sEachLine;
}
oReader.close();
oBuffer.close();
JSONObject object = new JSONObject(sText);
//Sjekk om pakken er registrert eller ikke
Posten posten = new Posten();
// Posten posten = new Posten();
HenteFelt henteFelt = new HenteFelt();
Boolean riktigSporing = posten.sjekkSporingsNummer(object);
if (riktigSporing == false) {
tv.setText("Sporingsnummeret er feil eller så er ikke pakken registrert hos posten enda.");
} else if (riktigSporing == true) {
String sentDato = henteFelt.sentDato(object); // do function and return string
String lesSisteStatus = henteFelt.lesSisteStatus(object);
String antallEventer = henteFelt.antallEventer(object);
String avsenderLand = henteFelt.avsenderLand(object);
String samleStatuser = henteFelt.samleStatuser(object);
String hentetDatoTid = henteFelt.hentetDatoTid(object);
if (lesSisteStatus.contentEquals("Du har hentet pakken !")) {
combine = "Du hentet pakken den : " + hentetDatoTid;
tv.setTextSize(20);
} else {
combine = sentDato + "\n" + lesSisteStatus + "\n" + antallEventer + "\n" + avsenderLand + "\n" + "\n" + samleStatuser;
tv.setTextSize(12);
}
tv.setText(combine);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
}
public boolean sjekkSporingsNummer(JSONObject object) {
Boolean riktigSporing = null;
try {
JSONArray consignmentSet = object.getJSONArray("consignmentSet");
JSONObject object1 = consignmentSet.getJSONObject(0);
JSONObject object2 = object1.getJSONObject("error");
String s = object2.getString("message");
s = "WORKS";
riktigSporing = false;
} catch (Exception e) {
e.printStackTrace();
riktigSporing = true;
String ss = "FAIL";
}
return riktigSporing;
}
class GetData extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... data) {
String URL = "http://sporing.bring.no/sporing.json?q=" + data[0];
String jsonReturnText = "";
HttpParams httpParameters = new BasicHttpParams();
int timeoutConnection = 10000; // 10 second timeout for connecting to site
HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
int timeoutSocket = 30000; // 30 second timeout for obtaining results
HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);
HttpClient httpclient = new DefaultHttpClient(httpParameters);
HttpGet httpget = new HttpGet(URL);
try {
HttpResponse response = httpclient.execute(httpget);
HttpEntity r_entity = response.getEntity();
jsonReturnText = EntityUtils.toString(r_entity);
} catch (Exception e) {
jsonReturnText = e.getMessage();
}
String s = "";
try {
final JSONObject oData = new JSONObject(jsonReturnText);
} catch (JSONException e) {
e.printStackTrace();
}
return jsonReturnText;
}
protected void onPostExecute(String result) {
string(et_sporingsnummer.getText().toString(), result);
}
}
}