Riferimento dell'oggetto null su TextView in GetView ()

Question

Ecco il mio codice adattatore;Tieni presente per il ListView che sto restituendo due tipi di viste. (LogCat sotto il codice`)

public class ItemAdapter extends ArrayAdapter<Item> {
   private LayoutInflater inflater;

  public ItemAdapter(Context context, ArrayList<Item> userItemObjectList) {
      super(context, R.layout.item_row_layout, userItemObjectList);

      inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

}

@Override
public int getViewTypeCount() {
    return 2;
}

class ViewHolder {
    TextView t1;
    TextView t2;
    TextView t3;
    TextView t4;
    TextView t6;
}

@Override
public int getItemViewType(int pos) {
    Item i = getItem(pos);
    String season = i.season;
    if (!season.equals(lastSeason)) {
        return 1;
    } else {
        return 0;
    }
}


@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder;
    int rowType = getItemViewType(position);

    if (convertView == null) {
        holder = new ViewHolder();

        if (rowType == 0) {
            convertView = inflater.inflate(R.layout.item_row_layout, parent,
                    false);

            holder.t1 = (TextView) convertView.findViewById(R.id.itemName);
            holder.t3 = (TextView) convertView
                    .findViewById(R.id.tvReviewTotalForItem);
            holder.t4 = (TextView) convertView
                    .findViewById(R.id.tvPercentageItems);
            holder.t6 = (TextView) convertView
                    .findViewById(R.id.tvItemRowReviewLabel);

            convertView.setTag(holder);

        } else if (rowType == 1) {

           convertView = inflater.inflate(R.layout.row_season, parent,
                    false);

            holder.t2 = (TextView) convertView.findViewById(R.id.seasonNumber);

            convertView.setTag(holder);
        }

    } else {
        holder = (ViewHolder) convertView.getTag();
    }

    Item i = getItem(position);
    String episode = i.item;
    String rating = i.ratings;
    String review = i.reviews;

    if (rowType == 1) {

        String season = i.season;
        lastSeason = season;
        holder.t2.setText("Season " + lastSeason);

    } else if (rowType == 0) {

        holder.t1.setText(episode); // THIS IS WHERE NULL TEXTVIEW IS FOUND
        holder.t3.setText(review);
        holder.t4.setText(rating);
        holder.t4.setText(rating);

    }


    return convertView;
}

.

}

Ecco il mio LogCat:

07-28 09:50:02.689: E/AndroidRuntime(7685): Process: com.---.---, PID: 7685
07-28 09:50:02.689: E/AndroidRuntime(7685): java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
07-28 09:50:02.689: E/AndroidRuntime(7685):     at com.---.---.ItemAdapter.getView(ItemAdapter.java:181)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.widget.HeaderViewListAdapter.getView(HeaderViewListAdapter.java:220)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.widget.AbsListView.obtainView(AbsListView.java:2255)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.widget.ListView.makeAndAddView(ListView.java:1790)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.widget.ListView.fillDown(ListView.java:691)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.widget.ListView.fillGap(ListView.java:655)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.widget.AbsListView.trackMotionScroll(AbsListView.java:5143)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.widget.AbsListView.scrollIfNeeded(AbsListView.java:3243)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.widget.AbsListView.onTouchMove(AbsListView.java:3587)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.widget.AbsListView.onTouchEvent(AbsListView.java:3431)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.View.dispatchTouchEvent(View.java:7706)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2210)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1945)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2068)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1515)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.app.Activity.dispatchTouchEvent(Activity.java:2458)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2016)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.View.dispatchPointerEvent(View.java:7886)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:3947)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3826)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3392)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3442)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3411)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3518)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3419)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3575)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3392)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3442)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3411)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3419)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3392)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:5532)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:5512)
07-28 09:50:02.689: E/AndroidRuntime(7685):     at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:548

.

Ho confermato, attraverso la registrazione, che il TextView NULL è in rowType 0. È nullo quando convertView is NOT Null (quindi succede quando si ricicla le viste).

Answer 1

Ho avuto un una volta un problema simile, l'ho risolto creando gli esperti separati per ogni layout:

    @Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder;
    ViewHolder2 holder2;
    int rowType = getItemViewType(position);

    if (convertView == null) {


        if (rowType == 0) {
            holder = new ViewHolder();
            convertView = inflater.inflate(R.layout.item_row_layout, parent,
                    false);

            holder.t1 = (TextView) convertView.findViewById(R.id.itemName);
            holder.t3 = (TextView) convertView
                    .findViewById(R.id.tvReviewTotalForItem);
            holder.t4 = (TextView) convertView
                    .findViewById(R.id.tvPercentageItems);
            holder.t6 = (TextView) convertView
                    .findViewById(R.id.tvItemRowReviewLabel);

            convertView.setTag(holder, R.layout.item_row_layout);

        } else if (rowType == 1) {
           holder2 = new ViewHolder2();
           convertView = inflater.inflate(R.layout.row_season, parent,
                    false);

            holder2.t2 = (TextView) convertView.findViewById(R.id.seasonNumber);

            convertView.setTag(holder, R.layout.row_season);
        }

    } else {
        if (rowType == 0) {
            holder = (ViewHolder) convertView.getTag(R.layout.item_row_layout);
        } else if (rowType == 1) {
            holder2 = (ViewHolder2) convertView.getTag(R.layout.row_season);
        }
    }

    Item i = getItem(position);
    String episode = i.item;
    String rating = i.ratings;
    String review = i.reviews;

    if (rowType == 1) {

        String season = i.season;
        lastSeason = season;
        holder2.t2.setText("Season " + lastSeason);

    } else if (rowType == 0) {

        holder.t1.setText(episode); // THIS IS WHERE NULL TEXTVIEW IS FOUND
        holder.t3.setText(review);
        holder.t4.setText(rating);
        holder.t4.setText(rating);

    }


    return convertView;
}

.

Aspettitori:

static class ViewHolder {
    TextView t1;
    TextView t3;
    TextView t4;
    TextView t6;
}

static class ViewHolder2 {
    TextView t2;
}

.

Answer 2

Hai detto che il rowType è 1 (attraverso il debug) ma il null appare all'interno del If statement in cui il rowType è 0 (si ha un commento nella prima riga di questo se lo indica).

Answer 3

È necessario impostare il testo su TextVisualizza prima che sia stato inizializzato