Android Spinner Fatal Exception: java.lang.ArrayIndexOutOfBoundsException: length=0; index=-1

Question

We recently went live with an app after months of testing and we are getting an exception related to a Spinner (only Samsung devices so far). Although we have the stacktraces, we can't gather much information from them so I was hoping someone could offer some help.

The issue is related to a HintAdapter. It seems the adapter has zero items when getItem and getView are called. We don't really understand how this is happening, but what is really concerning us is why the index being requested is -1. How can someone select a negative index?

Here is the stacktrace:

Fatal Exception: java.lang.ArrayIndexOutOfBoundsException: length=0; index=-1
   at java.util.ArrayList.get(ArrayList.java:413)
   at ca.example.mb.android.myexample.adapter.AbstractHintArrayAdapter.getItem(AbstractHintArrayAdapter.java:73)
   at ca.example.mb.android.myexample.adapter.AbstractHintArrayAdapter.getView(AbstractHintArrayAdapter.java:136)
   at android.widget.Spinner.makeView(Spinner.java:800)
   at android.widget.Spinner.layout(Spinner.java:748)
   at android.widget.Spinner.onLayout(Spinner.java:710)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
   at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1730)
   at android.widget.TableRow.onLayout(TableRow.java:122)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
   at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
   at android.widget.TableLayout.onLayout(TableLayout.java:445)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
   at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
   at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
   at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
   at android.widget.ScrollView.onLayout(ScrollView.java:2534)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1079)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.support.v4.view.ViewPager.onLayout(ViewPager.java:1795)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.support.design.widget.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:131)
   at android.support.design.widget.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:42)
   at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1391)
   at android.support.design.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:870)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
   at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
   at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1730)
   at android.widget.LinearLayout.onLayout(LinearLayout.java:1496)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.support.design.widget.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:131)
   at android.support.design.widget.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:42)
   at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1391)
   at android.support.design.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:870)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:1193)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
   at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
   at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
   at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
   at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
   at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
   at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
   at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
   at com.android.internal.policy.DecorView.onLayout(DecorView.java:935)
   at android.view.View.layout(View.java:18874)
   at android.view.ViewGroup.layout(ViewGroup.java:5954)
   at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2697)
   at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2413)
   at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1550)
   at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7189)
   at android.view.Choreographer$CallbackRecord.run(Choreographer.java:959)
   at android.view.Choreographer.doCallbacks(Choreographer.java:734)
   at android.view.Choreographer.doFrame(Choreographer.java:670)
   at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:945)
   at android.os.Handler.handleCallback(Handler.java:751)
   at android.os.Handler.dispatchMessage(Handler.java:95)
   at android.os.Looper.loop(Looper.java:154)
   at android.app.ActivityThread.main(ActivityThread.java:6776)
   at java.lang.reflect.Method.invoke(Method.java)
   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)

Here is the HintArrayAdapter getItem and getView methods:

public T getItem(int position)
{
    return optionElements.get(position);
}

public View getView(int position, View convertView, @NonNull ViewGroup parent)
{
    ViewHolder viewHolder;

    if (convertView == null)
    {
        viewHolder = new ViewHolder();
        LayoutInflater inflater = LayoutInflater.from(this.getContext());
        convertView = inflater.inflate(R.layout.search_spinner_item, parent, false);
        viewHolder.textView = (TextView) convertView.findViewById(R.id.search_spinner_item_text_view);
        convertView.setTag(viewHolder);
    }
    else
    {
        viewHolder = (ViewHolder) convertView.getTag();
    }

    T optionElement = getItem(position);

    if (optionElement != null)
    {
        String textToDisplay = getViewText(optionElement);
        viewHolder.textView.setText(textToDisplay);
    }

    return convertView;
}

Answer 1

It seems you are trying to select an element in your array of data that doesn't exist, the log says that you don't have any element but trying to reach index 1.