java - Android:索引 0 无效，大小为 0。在哪里？

Question

我收到一个无效的索引 0，大小为 0 错误，无法弄清楚这是在哪里发生的。我一直在运行调试器，但无法放置它。我所知道的是我的代码之前发生了什么以及之后会发生什么。下面我发布了 logcat，崩溃前完成的代码，以及之后将运行的内容。

这是日志:

  java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
        at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
        at java.util.ArrayList.get(ArrayList.java:308)
        at android.widget.HeaderViewListAdapter.isEnabled(HeaderViewListAdapter.java:164)
        at android.widget.ListView.dispatchDraw(ListView.java:3307)
        at android.view.View.draw(View.java:15174)
        at android.widget.AbsListView.draw(AbsListView.java:4318)
        at android.view.View.updateDisplayListIfDirty(View.java:14096)
        at android.view.View.getDisplayList(View.java:14119)
        at android.view.View.draw(View.java:14895)
        at android.view.ViewGroup.drawChild(ViewGroup.java:3407)
        at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3201)
        at android.view.View.draw(View.java:15174)
        at android.view.View.updateDisplayListIfDirty(View.java:14096)
        at android.view.View.getDisplayList(View.java:14119)
        at android.view.View.draw(View.java:14895)
        at android.view.ViewGroup.drawChild(ViewGroup.java:3407)
        at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3201)
        at android.view.View.updateDisplayListIfDirty(View.java:14091)
        at android.view.View.getDisplayList(View.java:14119)
        at android.view.View.draw(View.java:14895)
        at android.view.ViewGroup.drawChild(ViewGroup.java:3407)
        at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3201)
        at android.view.View.updateDisplayListIfDirty(View.java:14091)
        at android.view.View.getDisplayList(View.java:14119)
        at android.view.View.draw(View.java:14895)
        at android.view.ViewGroup.drawChild(ViewGroup.java:3407)
        at android.support.v4.widget.DrawerLayout.drawChild(DrawerLayout.java:1089)
        at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3201)
        at android.view.View.updateDisplayListIfDirty(View.java:14091)
        at android.view.View.getDisplayList(View.java:14119)
        at android.view.View.draw(View.java:14895)
        at android.view.ViewGroup.drawChild(ViewGroup.java:3407)
        at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3201)
        at android.view.View.updateDisplayListIfDirty(View.java:14091)
        at android.view.View.getDisplayList(View.java:14119)
        at android.view.View.draw(View.java:14895)
        at android.view.ViewGroup.drawChild(ViewGroup.java:3407)
        at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3201)
        at android.view.View.updateDisplayListIfDirty(View.java:14091)
        at android.view.View.getDisplayList(View.java:14119)
        at android.view.View.draw(View.java:14895)
        at android.view.ViewGroup.drawChild(ViewGroup.java:3407)
        at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3201)
        at android.view.View.updateDisplayListIfDirty(View.java:14091)
        at android.view.View.getDisplayList(View.java:14119)
        at android.view.View.draw(View.java:14895)
        at android.view.ViewGroup.drawChild(ViewGroup.java:3407)
        at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3201)
        at android.view.View.updateDisplayListIfDirty(View.java:14091)
        at android.view.View.getDisplayList(View.java:14119)
        at android.view.View.draw(View.java:14895)
        at android.view.ViewGroup.drawChild(ViewGroup.java:3407)
        at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3201)
        at android.view.View.updateDisplayListIfDirty(View.java:14091)
        at android.view.View.getDisplayList(View.java:14119)
        at android.view.View.draw(View.java:14895)
        at android.view.ViewGroup.drawChild(ViewGroup.java:3407)
        at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3201)
        at android.view.View.draw(View.java:15174)
        at android.widget.FrameLayout.draw(FrameLayout.java:592)
        at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:2695)
        at android.view.View.updateDisplayListIfDirty(View.java:14096)
        at android.view.View.getDisplayList(View.java:14119)
        at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:266)
        at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:272)
        at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:311)
        at android.view.ViewRootImpl.draw(ViewRootImpl.java:2531)
        at android.view.

这是我之前的代码，它完成了:

   @Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    Answer a = null;
    if(position -1 >= 0 && myAnswerNotices.size() > position -1){
        a = myAnswerNotices.get(position-1);
        QuestionFragment.clicked_Question = a.getQuestion();
    }

    // Go to question view
    Intent intent;

    if(QuestionFragment.clicked_Question.getType().equals( "poll"))
        intent = new Intent (getActivity(), PollViewActivity.class);
    else
        intent = new Intent (getActivity(), QuestionViewActivity.class);

    if(a != null) {
        if (preferences.contains("notice_" + a.getObjectId())) {
            editor.remove("notice_" + a.getObjectId());
            editor.commit();
        }

        if (myAnswerNotices != null && !myAnswerNotices.isEmpty() && myAnswerNotices.contains(a))
            myAnswerNotices.remove(a);
    }

    startActivity(intent);

}

这是应该在之后开始的代码:

  @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    overridePendingTransition(R.anim.slide_in_right, R.anim.slide_out_left);
    setContentView(R.layout.activity_question_view);

    Toolbar toolbar = (Toolbar) findViewById(R.id.question_view_toolbar);
    setSupportActionBar(toolbar);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setHomeButtonEnabled(true);

    share = (ImageButton) findViewById(R.id.questionView_share_image_button);
    emailButton = (Button) findViewById(R.id.questionView_email_button);
    title = (TextView) findViewById(R.id.questionView_title_text_view);
    username = (TextView) findViewById(R.id.questionView_askedBy_text_view);
    createdAt = (TextView) findViewById(R.id.questionView_createdAt_text_view);
    followingTextView = (TextView) findViewById(R.id.questionView_follow_textview);

    setupQuestion();
    setListeners();
    setupList();

}

@科林:

myAnswerNotices 被初始化为一个成员变量:

public class NotificationFragment extends Fragment
    implements AdapterView.OnItemClickListener, SwipeRefreshLayout.OnRefreshListener {

private final List<Answer> myAnswerNotices = new ArrayList<>();

并填充在一个 AsyncTask 中:公共(public)类 RefreshTask 扩展 AsyncTask> {

    @Override
    protected void onPreExecute() {
        mRefreshWrapper.setRefreshing(true);
       // Activity.pinAll();
    }

    @Override
    protected List<Answer> doInBackground(Object... params) {

        //myAnswerNotices.clear();
       // List<Activity> a_list = new ArrayList<>();
        try {
            activityNotifications.addAll(Activity.getQuery()
                    .whereEqualTo(Constants.kQollegeActivityTypeKey, Constants.kQollegeActivityTypeAnswerPosted)
                    .whereEqualTo(Constants.kQollegeActivityToUserKey, ParseUser.getCurrentUser())
                    .whereGreaterThan(Constants.kQollegeQuestionCreatedAtKey, checked)
                    .orderByDescending(Constants.kQollegeQuestionCreatedAtKey)
                    .include(Constants.kQollegeActivityAnswerKey)
                    .find());
        } catch (ParseException e) {
            e.printStackTrace();
        }
        checked = Calendar.getInstance().getTime();
        editor.putLong("notification_checked",checked.getTime());
        editor.commit();


        for(String s : preferences.getAll().keySet()){
            if(s.contains("notice_")){
                String a_id = preferences.getString(s, null);
                if(a_id != null){
                    try {
                        myAnswerNotices.add(Answer.getQuery().get(a_id));
                    } catch (ParseException e) {
                        e.printStackTrace();
                    }
                }
            }
        }

        for(Activity a : activityNotifications){
            myAnswerNotices.add(a.getAnswer());
        }

        return myAnswerNotices;

    }

    @Override
    protected void onPostExecute(List<Answer> list) {
        if(!myAnswerNotices.isEmpty())
            mHeaderTextView.setVisibility(View.GONE);
        else {
            mHeaderTextView.setText("No notifications");
            mHeaderTextView.setVisibility(View.VISIBLE);
        }

        mRefreshWrapper.setRefreshing(false);

    }

@瓦莎:这是与我的适配器初始化相关的代码:

NotificationListAdapter mListAdapter = new NotificationListAdapter(getActivity(), R.layout.notification_list_item, myAnswerNotices);
    mRefreshWrapper.getListView().setAdapter(mListAdapter);
    mListAdapter.setNotifyOnChange(true);

@泰特斯:这是我的整个适配器类:

class NotificationListAdapter extends ArrayAdapter {

private final int mResourceId;
private final LayoutInflater inflater;
private final Context context;
private NotificationListItemHolder notificationView;
private Answer answer;

public NotificationListAdapter(Context ctx, int resourceId, List objects){
    super(ctx,resourceId,objects);
    mResourceId = resourceId;
    inflater = LayoutInflater.from(ctx);
    context = ctx;
}

@Override
public View getView (int position, View convertView, ViewGroup parent) {
    answer = (Answer) getItem(position);

    // Get or create cached eventView
    if(convertView == null){
        convertView =  inflater.inflate(mResourceId, null);
        notificationView = new NotificationListItemHolder(convertView);
        convertView.setTag(notificationView);
    }
    else {
        notificationView = (NotificationListItemHolder) convertView.getTag();
    }
    TextView name = notificationView.getPostedByTextView();
    name.setTag(answer);
    // Fill Data
    fillData();

    name.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Intent intent = new Intent(context, ProfileActivity.class);
            Answer a = (Answer) v.getTag();
            ParseUser u = a.getPostedBy();

            intent.putExtra("User", u.getObjectId());
            context.startActivity(intent);
        }
    });



    return convertView;
}

private void fillData(){
    try {
        Question q = answer.getQuestion().fetch();
        notificationView.getTitleTextView().setText(q.getTitle());
    } catch (ParseException e) {
        e.printStackTrace();
    }
    notificationView.getPostedByTextView().setText(answer.getPostedByText());
    notificationView.getCreatedAtTextView().setText(answer.getCreatedAtText());
}

Answer 1

注意:我没有足够的声誉来发表评论，所以写下这个答案。

适配器中的 getCount() 方法似乎只是覆盖了该方法:

if(myAnswerNotices == null || myAnswerNotices.size()>0)
return myAnswerNotices.size();
else 
return 0;

希望对您有所帮助。谢谢