滚动时，Android适配器抛出IndexOutOfBoundsException

Question

从firebase，我看到了很多崩溃日志：

Fatal Exception: java.lang.IndexOutOfBoundsException
Invalid index 7, size is 0
java.util.ArrayList.throwIndexOutOfBoundsException (ArrayList.java:255)
java.util.ArrayList.get (ArrayList.java:308)
com.weex.app.adapters.CartoonReaderAdapter.getItemViewType (CartoonReaderAdapter.java:357)
android.widget.AbsListView$RecycleBin.getScrapView (AbsListView.java:7132)
android.widget.AbsListView.obtainView (AbsListView.java:2469)
android.widget.ListView.makeAndAddView (ListView.java:1920)
android.widget.ListView.fillUp (ListView.java:751)
android.widget.ListView.fillGap (ListView.java:690)
android.widget.AbsListView.trackMotionScroll (AbsListView.java:5579)
android.widget.AbsListView.scrollIfNeeded (AbsListView.java:3641)
android.widget.AbsListView.startScrollIfNeeded (AbsListView.java:3569)
android.widget.AbsListView.onInterceptTouchEvent (AbsListView.java:4711)
android.view.ViewGroup.dispatchTouchEvent (ViewGroup.java:2157)

似乎adapter.getItemViewType扔投掷IndexOutOfBoundsException。我检查了我的代码，所有notifyDataSetChanged都在主线程中调用。这是我的适配器代码：

@Override
  public void notifyDataSetChanged() {
    Log.e("TAG","notify data change:"+Thread.currentThread().getName());
    rebuildViewTypes();
    super.notifyDataSetChanged();
  }

  @Override
  public int getCount() {
    return viewTypes == null ? 0 : viewTypes.size();
  }

  private void rebuildViewTypes() {
    viewTypes.clear();
    if (pictures == null || pictures.size() == 0) {
      return;
    }
    CartoonReaderTypeItem item = null;

    if (topGap > 0) {
      item = new CartoonReaderTypeItem();
      item.type = LIST_ITEM_TYPE_GAP;
      viewTypes.add(item);
    }

    if (topHint != null) {
      item = new CartoonReaderTypeItem();
      item.type = LIST_ITEM_TYPE_TOP_HINT;
      viewTypes.add(item);
    }

    if (pictures != null) {
      for (int i = 0; i < pictures.size(); i++) {
        PictureItem pictureItem = pictures.get(i);
        item = new CartoonReaderTypeItem();
        item.type = LIST_ITEM_TYPE_PICTURE;
        item.item = pictureItem;
        viewTypes.add(item);
      }
    }
  }

  @Override
  public Object getItem(int position) {
    CartoonReaderTypeItem item = viewTypes.get(position);
    return item.item;
  }

  @Override
  public long getItemId(int position) {
    return 0;
  }

  @Override
  public int getViewTypeCount() {
    return 16;
  }

  /**
   * @param position
   * @return
   */
  @Override
  public int getItemViewType(int position) {
    CartoonReaderTypeItem item = viewTypes.get(position);
    return item.type;
  }

我糊涂了。应该在主线程中调用所有方法（dispatchTouchEvent和notifyDataSetChanged）。所以没有线程安全问题。 viewTypes数据可能是安全的。 IndexOutOfBoundsException超出了我的理解范围。

有什么好主意吗？

Answer 1

索引从0开始。在下面的代码中，您的位置可能比数组的索引高+1。所以请检查位置值。

    public int getItemViewType(int position) 
    {
           CartoonReaderTypeItem item = viewTypes.get(position);
           return item.type;
    } 

Answer 2

试试这可能有帮助 -

 @Override
 public int getItemId(int position) {
   return position;
  }

@Override
public int getViewTypeCount() {
 return viewTypes.size();
}