java.lang.RuntimeException: An error occured while executing doInBackground() 에 대해 질문드립니다...

Question

public class ReadData3 extends  AsyncTask<String, Integer, ArrayList<String>>
{
	
	String rst;
	MemberDTO act1;
	Context ctx1;
	String ID;
	String PASSWORD;
 	String AGE;
 	String NAME;
 	String LOGINFO;
	String MISSING;
	String PHONE;
	String RELATION;
	String ID2;
	String NAME2;
	
	public ReadData3(Context context, MemberDTO mainact){
		super();
		this.act1 = mainact;
		this.ctx1 = context;
	}

    public ReadData3(Context context, OnClickListener onClickListener) {
		// TODO Auto-generated constructor stub
	}

	@Override
    protected void onPostExecute(ArrayList<String> data) {
        super.onPostExecute(data);
    
	Handler mHandler = new Handler(Looper.getMainLooper());
	mHandler.postDelayed(new Runnable() {
	@Override
	public void run() {
	     // 내용
		
	}
	}, 0);
}
    @Override
    protected ArrayList<String> doInBackground(String... params) {
        try {
            JSONArray personsNames = act1.getPersonsData1();//여기
            ArrayList<String> persons = new ArrayList<String>();

          for(int i=0; i< personsNames.length(); i++)
           {
            	String fullname = personsNames.getJSONObject(i).getString("ID") + "/" + personsNames.getJSONObject(i).getString("PASSWORD")+ "/" + personsNames.getJSONObject(i).getString("NAME")+ "/" + personsNames.getJSONObject(i).getString("AGE")+ "/" + personsNames.getJSONObject(i).getString("PHONE")+ "/" + personsNames.getJSONObject(i).getString("0")+ "/" + personsNames.getJSONObject(i).getString("ID2")+ "/" + personsNames.getJSONObject(i).getString("RELATION")+ "/" + personsNames.getJSONObject(i).getString("MISSING");
                persons.add(fullname);
           }

            return persons;

        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }

08-04 16:17:23.293: E/AndroidRuntime(10403): FATAL EXCEPTION: AsyncTask #1
08-04 16:17:23.293: E/AndroidRuntime(10403): java.lang.RuntimeException: An error occured while executing doInBackground()
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at android.os.AsyncTask$3.done(AsyncTask.java:278)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at java.util.concurrent.FutureTask.run(FutureTask.java:137)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at java.lang.Thread.run(Thread.java:856)
08-04 16:17:23.293: E/AndroidRuntime(10403): Caused by: java.lang.NullPointerException
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at com.example.jsonsampleapp.ReadData3.doInBackground(ReadData3.java:71)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at com.example.jsonsampleapp.ReadData3.doInBackground(ReadData3.java:1)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at android.os.AsyncTask$2.call(AsyncTask.java:264)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
08-04 16:17:23.293: E/AndroidRuntime(10403): 	... 5 more

밑은로그입니다 java.lang.RuntimeException: An error occured while executing doInBackground() 이게 왜 뜨는지 잘 모르겠습니다..ㅠㅠ

 for(int i=0; i< personsNames.length(); i++)

           {

            String fullname = personsNames.getJSONObject(i).getString("ID") + "/" + personsNames.getJSONObject(i).getString("PASSWORD")+ "/" + personsNames.getJSONObject(i).getString("NAME")+ "/" + personsNames.getJSONObject(i).getString("AGE")+ "/" + personsNames.getJSONObject(i).getString("PHONE")+ "/" + personsNames.getJSONObject(i).getString("0")+ "/" + personsNames.getJSONObject(i).getString("ID2")+ "/" + personsNames.getJSONObject(i).getString("RELATION")+ "/" + personsNames.getJSONObject(i).getString("MISSING");

                persons.add(fullname);

           } 여기가 71번째 줄입니다 ReadData3

Answer 1

An error occurred while executing doInBackground() 이 에러는 doInBackground()를 실행하는 동안 에러가 났다는거고,

에러 내용은 아래 NullPointerException을 보시면 됩니다.

ReadData3 클래스에서 71번째 줄에서 에러가 나는거니 거기서 사용하는 객체가 NULL 인지 확인해 보세요.