私のアプリケーションは私に FATAL EXCEPTION: AsyncTask #2 エラーを与えているようです.誰かが私のコードを見て何が間違っているのか教えてくれませんか.
スタックトレース
07-27 07:58:42.301: E/AndroidRuntime(926): FATAL EXCEPTION: AsyncTask #2
07-27 07:58:42.301: E/AndroidRuntime(926): java.lang.RuntimeException: An error occured while executing doInBackground()
07-27 07:58:42.301: E/AndroidRuntime(926): at android.os.AsyncTask$3.done(AsyncTask.java:299)
07-27 07:58:42.301: E/AndroidRuntime(926): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
07-27 07:58:42.301: E/AndroidRuntime(926): at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
07-27 07:58:42.301: E/AndroidRuntime(926): at java.util.concurrent.FutureTask.run(FutureTask.java:239)
07-27 07:58:42.301: E/AndroidRuntime(926): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
07-27 07:58:42.301: E/AndroidRuntime(926): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
07-27 07:58:42.301: E/AndroidRuntime(926): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
07-27 07:58:42.301: E/AndroidRuntime(926): at java.lang.Thread.run(Thread.java:856)
07-27 07:58:42.301: E/AndroidRuntime(926): Caused by: java.lang.NullPointerException
07-27 07:58:42.301: E/AndroidRuntime(926): at com.theproblemsolver.ListView$LoadAllData.doInBackground(ListView.java:92)
07-27 07:58:42.301: E/AndroidRuntime(926): at com.theproblemsolver.ListView$LoadAllData.doInBackground(ListView.java:1)
07-27 07:58:42.301: E/AndroidRuntime(926): at android.os.AsyncTask$2.call(AsyncTask.java:287)
07-27 07:58:42.301: E/AndroidRuntime(926): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
07-27 07:58:42.301: E/AndroidRuntime(926): ... 4 more
主な活動
public class MainActivity extends Activity {
EditText et;
Button getanswer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button getanswer = (Button) findViewById(R.id.button1);
getanswer.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(MainActivity.this, ListView.class);
startActivity(i);
}
});
}
}
ListView アクティビティ
public class ListView extends ListActivity {
private ProgressDialog pDialog;
JSONParsser jParser = new JSONParsser();
ArrayList<HashMap<String, String>> questionList;
private static String URI = "http://example.com/json";;
//JSONObject json = jParser.getJSONFromURI(URI);
final String TAG_RESULTS = "ResultsSet";
final String TAG_SUBJECT = "Subject";
final String TAG_NUMANSWERS = "NumAnswers";
final String TAG_QUESTION = "Question";
final String TAG_QUESTION_CONTENT = "Content";
final String TAG_QUESTION_CHOSENANSWER = "ChosenAnswer";
final String TAG_QUESTION_ANSWERS = "Answers";
JSONArray ResultsSet = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.listview);
questionList = new ArrayList<HashMap<String, String>>();
new LoadAllData().execute();
android.widget.ListView lv = getListView();
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,int position, long id) {
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == 100) {
Intent intent = getIntent();
finish();
startActivity(intent);
}
}
class LoadAllData extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(ListView.this);
pDialog.setMessage("Loading Data. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
protected String doInBackground(String... args) {
try {
JSONObject json = jParser.getJSONFromURI(URI);
ResultsSet = json.getJSONArray(TAG_RESULTS);
for(int i = 0; i < ResultsSet.length(); i++) {
JSONObject r = ResultsSet.getJSONObject(i);
String Subject = r.getString(TAG_SUBJECT);
String NumAnswers = r.getString(TAG_NUMANSWERS);
JSONObject Question = r.getJSONObject(TAG_QUESTION);
String Content = Question.getString(TAG_QUESTION_CONTENT);
String ChosenAnswer = Question.getString(TAG_QUESTION_CHOSENANSWER);
String Answers = Question.getString(TAG_QUESTION_ANSWERS);
HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_SUBJECT, Subject);
map.put(TAG_NUMANSWERS, NumAnswers);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String file_URI) {
pDialog.dismiss();
runOnUiThread(new Runnable() {
public void run() {
ListAdapter adapter = new SimpleAdapter(getBaseContext(), questionList,
R.layout.row,
new String[] { TAG_SUBJECT, TAG_NUMANSWERS }, new int[] {
R.id.Subject, R.id.NumAnswers });
setListAdapter(adapter);
}
});
}
}}
SingleListItem アクティビティ
public class SingleListItem extends Activity {
TextView subject;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.singlelistitem);
subject = (TextView) findViewById(R.id.Subject2);
Intent i = getIntent();
String Subject = i.getStringExtra("TAG_SUBJECT");
subject.setText(Subject);
}
}