我现在正在开发一款Android应用程序，现在情况一直很顺利。但突然间我得到一个空指针错误，无法找出问题所在。事情是应用程序之前工作正常。我突然得到了这个错误。我可能会意外地做一些事情，现在我无法弄清楚我做错了什么
根据log cat，错误在这些类中
TheaterFragment类
package com.fortuna.cinemalk;
import java.util.ArrayList;
import android.app.Activity;
import android.app.FragmentManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
import android.content.Intent;
import android.widget.AdapterView;
import com.fortuna.cinemalk.adapter.LazyAdapter;
import com.fortuna.cinemalk.model.BaseElement;
import com.fortuna.cinemalk.service.CommonVariable;
import com.fortuna.cinemalk.service.JSONServices;
import com.fortuna.cinemalk.util.Element;
public class TheaterFragment extends Fragment {
private GridView gridView;
private ArrayList<BaseElement> filmTheater;
private LazyAdapter adapter;
private Activity activity;
private CommonVariable commonVariable;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.theater_fragment, container,
false);
activity = this.getActivity();
commonVariable = (CommonVariable) activity.getApplication();
gridView = (GridView) view.findViewById(R.id.gridView1);
gridView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
android.support.v4.app.Fragment detail = new TheaterDetailFragment();
android.support.v4.app.FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().add(R.id.content_frame, detail).addToBackStack("back").commit();
}
});
new BackGround().execute();
return view;
}
public class BackGround extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... params) {
filmTheater = JSONServices.getTheater();
return null;
}
@Override
/* check again */
protected void onPostExecute(Void result) {
commonVariable.setTheater(filmTheater);
adapter = new LazyAdapter(filmTheater, activity,Element.THEATER_LIST.getType());
gridView.setAdapter(adapter);
super.onPostExecute(result);
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
}
}
}
JSON服务类
package com.fortuna.cinemalk.service;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.graphics.Paint.Join;
import android.widget.TextView;
import com.fortuna.cinemalk.model.BaseElement;
import com.fortuna.cinemalk.model.Film;
import com.fortuna.cinemalk.model.FilmBanner;
import com.fortuna.cinemalk.model.FilmCategory;
import com.fortuna.cinemalk.model.Home;
import com.fortuna.cinemalk.model.Theater;
import com.fortuna.cinemalk.util.JSONTag;
import com.fortuna.cinemalk.util.ServiceURL;
public class JSONServices {
public static ArrayList<BaseElement> getCategory() {
ArrayList<BaseElement> catogory = new ArrayList<BaseElement>();
try {
JSONObject jsonObject = new JSONObject(
CommonService.readJsonUrl(ServiceURL.CATEGORY_TOPCAT
.getUrl()));
JSONArray array = jsonObject.getJSONArray(JSONTag.CATEGORY.getTag());
for (int i = 0; i < array.length(); i++) {
JSONObject jsonObj = array.getJSONObject(i);
FilmCategory filmCategory = new FilmCategory();
filmCategory.setCatId(jsonObj.getString(JSONTag.ID.getTag()));
filmCategory.setCategory(jsonObj.getString(JSONTag.NAME
.getTag()));
catogory.add(filmCategory);
// news.put(i, newsCategory);
}
} catch (JSONException e) {
e.printStackTrace();
return null;
}
return catogory;
}
public static ArrayList<BaseElement> getCategoryById(String id) {
ArrayList<BaseElement> films = new ArrayList<BaseElement>();
try {
JSONObject jsonObject = new JSONObject(CommonService.readJsonFromUrl(ServiceURL.MOVE_BY_CATEGORY
.getUrl() + id));
JSONArray array = jsonObject.getJSONArray(JSONTag.MOVIE.getTag());
for (int i = 0; i < array.length(); i++) {
JSONObject jsonObj = array.getJSONObject(i);
Film film = new Film();
film.setActorsActress(jsonObj.getString(JSONTag.ACTOER_ACTRESS
.getTag()));
film.setComposer(jsonObj.getString(JSONTag.COMPOSER.getTag()));
film.setDescrition(jsonObj.getString(JSONTag.DESCRIPTION
.getTag()));
film.setDirecter(jsonObj.getString(JSONTag.DIRECTOR.getTag()));
film.setGenre(jsonObj.getString(JSONTag.GENERE.getTag()));
film.setImage(jsonObj.getString(JSONTag.IMAGE_2.getTag()));
film.setIMDbRating(jsonObj.getString(JSONTag.IMDB_RATING
.getTag()));
film.setLength(jsonObj.getString(JSONTag.LENGTH.getTag()));
film.setNewsId(jsonObj.getString(JSONTag.ID.getTag()));
film.setPlot(jsonObj.getString(JSONTag.PLOT.getTag()));
film.setProducer(jsonObj.getString(JSONTag.PRODUCER.getTag()));
films.add(film);
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return films;
}
public static LinkedHashMap<Integer, BaseElement> getNewsDescription(
String id) {
LinkedHashMap<Integer, BaseElement> news = new LinkedHashMap<Integer, BaseElement>();
try {
JSONObject jsonObject = new JSONObject(
CommonService
.readJsonFromUrl(ServiceURL.CATEGOR_DESCRIPTION
.getUrl() + id));
JSONArray array = jsonObject.getJSONArray(JSONTag.TOPNEWSGIVENCAT.getTag());
for (int i = 0; i < array.length(); i++) {
JSONObject jsonObj = array.getJSONObject(i);
Film newsDescription = new Film();
newsDescription.setNewsId(jsonObj.getString(JSONTag.ID.getTag()));
newsDescription.setTitle(jsonObj.getString(JSONTag.TITLE.getTag()));
newsDescription.setShortDescription(jsonObj.getString(JSONTag.SHORTDESCRIPTION.getTag()));
newsDescription.setDescrition(jsonObj.getString(JSONTag.DESCRIPTION.getTag()));
newsDescription.setThumImage(jsonObj.getString(JSONTag.THUMBNAIL.getTag()));
newsDescription.setImage(jsonObj.getString(JSONTag.IMAGE.getTag()));
newsDescription.setTrailerImage(jsonObj.getString(JSONTag.TRAILER_IMAGE.getTag()));
newsDescription.setVideo(jsonObj.getString(JSONTag._VIDEO.getTag()));
news.put(i, newsDescription);
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return news;
}
public static LinkedHashMap<Integer, BaseElement> getHomeContent() {
LinkedHashMap<Integer, BaseElement> news = new LinkedHashMap<Integer, BaseElement>();
try {
JSONObject jsonObject = new JSONObject(
CommonService.readJsonFromUrl(ServiceURL.HOME_CONTENT
.getUrl()));
JSONArray array = jsonObject.getJSONArray("home");
for (int i = 0; i < array.length(); i++) {
JSONObject jsonObj = array.getJSONObject(i);
Home home = new Home();
JSONArray homeArray = jsonObj.getJSONArray("photos");
LinkedHashMap<Integer, BaseElement> banner = new LinkedHashMap<Integer, BaseElement>();
for (int j = 0; j < homeArray.length(); j++) {
JSONObject jsonObject2 = homeArray.getJSONObject(j);
FilmBanner filmBanner = new FilmBanner();
filmBanner.setId(jsonObject2.getString(JSONTag.ID.getTag()));
filmBanner.setTitle(jsonObject2.getString(JSONTag.TITLE.getTag()));
filmBanner.setDescription(jsonObject2.getString(JSONTag.SHORTDESCRIPTION.getTag()));
filmBanner.setImage(jsonObject2.getString(JSONTag.IMAGE.getTag()));
filmBanner.setThumb(jsonObject2.getString(JSONTag.THUMBNAIL.getTag()));
filmBanner.setType(jsonObject2.getString(JSONTag.TYPE.getTag()));
banner.put(j, filmBanner);
}
home.setCategory(jsonObj.getString(JSONTag.CATEGORY.getTag()));
home.setImages(banner);
news.put(i, home);
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return news;
}
public static ArrayList<BaseElement> getTheater() {
ArrayList<BaseElement> theaters = new ArrayList<BaseElement>();
try {
JSONObject jsonObject = new JSONObject(
CommonService.readJsonUrl(ServiceURL.THEATER_CONTENT
.getUrl()));
JSONArray array = jsonObject.getJSONArray("theater");
for (int i = 0; i < array.length(); i++) {
JSONObject jsonObj = array.getJSONObject(i);
Theater theater = new Theater();
theater.setTheaterId(jsonObj.getString(JSONTag.ID.getTag()));
theater.setTheaterImage(jsonObj.getString(JSONTag.IMAGE.getTag()));
theater.setName(jsonObj.getString(JSONTag.NAME.getTag()));
theaters.add(theater);
}
} catch (JSONException e) {
e.printStackTrace();
return null;
}
return theaters;
}
}
记录猫
08-12 13:58:55.241: E/AndroidRuntime(11709): FATAL EXCEPTION: AsyncTask #1
08-12 13:58:55.241: E/AndroidRuntime(11709): java.lang.RuntimeException: An error occured while executing doInBackground()
08-12 13:58:55.241: E/AndroidRuntime(11709): at android.os.AsyncTask$3.done(AsyncTask.java:200)
08-12 13:58:55.241: E/AndroidRuntime(11709): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
08-12 13:58:55.241: E/AndroidRuntime(11709): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
08-12 13:58:55.241: E/AndroidRuntime(11709): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
08-12 13:58:55.241: E/AndroidRuntime(11709): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
08-12 13:58:55.241: E/AndroidRuntime(11709): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
08-12 13:58:55.241: E/AndroidRuntime(11709): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
08-12 13:58:55.241: E/AndroidRuntime(11709): at java.lang.Thread.run(Thread.java:1096)
08-12 13:58:55.241: E/AndroidRuntime(11709): Caused by: java.lang.NullPointerException
08-12 13:58:55.241: E/AndroidRuntime(11709): at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:112)
08-12 13:58:55.241: E/AndroidRuntime(11709): at org.json.JSONTokener.nextValue(JSONTokener.java:90)
08-12 13:58:55.241: E/AndroidRuntime(11709): at org.json.JSONObject.<init>(JSONObject.java:154)
08-12 13:58:55.241: E/AndroidRuntime(11709): at org.json.JSONObject.<init>(JSONObject.java:171)
08-12 13:58:55.241: E/AndroidRuntime(11709): at com.fortuna.cinemalk.service.JSONServices.getTheater(JSONServices.java:210)
08-12 13:58:55.241: E/AndroidRuntime(11709): at com.fortuna.cinemalk.TheaterFragment$BackGround.doInBackground(TheaterFragment.java:75)
08-12 13:58:55.241: E/AndroidRuntime(11709): at com.fortuna.cinemalk.TheaterFragment$BackGround.doInBackground(TheaterFragment.java:1)
08-12 13:58:55.241: E/AndroidRuntime(11709): at android.os.AsyncTask$2.call(AsyncTask.java:185)
08-12 13:58:55.241: E/AndroidRuntime(11709): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
08-12 13:58:55.241: E/AndroidRuntime(11709): ... 4 more
08-12 13:59:24.294: E/ActivityThread(11807): Failed to find provider info for com.samsung.sec.android.clockpackage
08-12 13:59:25.563: E/WindowManager(2512): Overwriting rotation value from 0
08-12 13:59:25.622: E/Launcher(2609): setWindowOpaque()
08-12 13:59:25.735: E/Launcher(2609): setWindowOpaque()
08-12 14:03:57.817: E/Finsky(3371): [1] SelfUpdateScheduler.onError: Self-update failed because of HTTP error code: 495
08-12 14:04:08.298: E/Launcher(2609): setWindowOpaque()
答案 0 :(得分：1)
异常是NullPointerException并指向此语句：
JSONObject jsonObject = new JSONObject(
CommonService.readJsonUrl(ServiceURL.THEATER_CONTENT
.getUrl()));
所以我想可能是你将null参数传递给JSONObject类的构造函数。尝试打印参数以查看其格式是否正确。