filtering custom adapter IndexOutOfBoundsException

问题:

I'm novice at android.

My custom Adapter cause exception when filtering.

here is my code. private class DeptAdapter extends ArrayAdapter implements Filterable {

    private ArrayList<Dept> items;
    private ArrayList<Dept> mOriginalValues;

    public DeptAdapter(Context context, int textViewResourceId, ArrayList<Dept> items) {
            super(context, textViewResourceId, items);
            this.items = items;
    }
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View v = convertView;

        if (v == null) {
            LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            v = vi.inflate(R.layout.item_listview_2line, null);
        }
        Dept d = items.get(position);
        if (d != null) {
                TextView tt = (TextView) v.findViewById(R.id.toptext);
                TextView bt = (TextView) v.findViewById(R.id.bottomtext);
                if (tt != null){
                    tt.setText(d.dept_nm);                            
                }
                if(bt != null){
                    bt.setText(d.dept_cd);
                }
        }
        return v;
    }

    @Override
    public Filter getFilter() {
        Filter filter = new Filter() {

            @SuppressWarnings("unchecked")
            @Override
            protected void publishResults(CharSequence constraint,FilterResults results) {

                items = (ArrayList<Dept>) results.values; // has the filtered values
                if (results.count > 0) {
                    notifyDataSetChanged();
                } else {
                    notifyDataSetInvalidated();
                }
            }

            }
            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                FilterResults results = new FilterResults();        // Holds the results of a filtering operation in values
                ArrayList<Dept> FilteredArrList = new ArrayList<Dept>();

                if (mOriginalValues == null) {
                    mOriginalValues = new ArrayList<Dept>(items); // saves the original data in mOriginalValues
                }

                if (constraint == null || constraint.length() == 0) {

                    // set the Original result to return  
                    results.count = mOriginalValues.size();
                    results.values = mOriginalValues;
                } else {
                    constraint = constraint.toString().toLowerCase();
                    for (int i = 0; i < mOriginalValues.size(); i++) {
                        Dept d = mOriginalValues.get(i);
                        if (d.dept_cd.toLowerCase().startsWith(constraint.toString()) || d.dept_nm.toLowerCase().startsWith(constraint.toString())) {
                            FilteredArrList.add(d);
                        }
                    }
                    // set the Filtered result to return
                    results.count = FilteredArrList.size();
                    results.values = FilteredArrList;
                }
                return results;
            }
        };
        return filter;
    }
}

class Dept
{
    String dept_cd; 
    String dept_nm; 
    public Dept(String dept_cd, String dept_nm)
    {
        this.dept_cd = dept_cd;
        this.dept_nm = dept_nm;
    }
    public String toString()
    {
        return this.dept_nm+ "(" + this.dept_cd +")" ;
    }
}

help me anyone.... I can't understand why getView() method was invoked more then items.size()

回答1:

Keep in mind that getView() will query the size of the items that the superclass has, which right now, is what you originally passed it when calling the superclass constructor,

super(context, textViewResourceId, items);

Therefore, the superclass doesn't know that you've changed the size when you have filtered. This means getCount() will return the original size of the array, which is understandably larger than your filtered array.

This means You should override the getCount() method so you're sure that you're returning the actual valid size:

@Override
public int getCount()
{
   return items.size();
}

You should also override the other methods related to the List operations (such as getting) if you are going to be using them. Eg:

@Override
public Dept getItem (int pos){
     return items.get(pos);
}

回答2:

You need to add this methods for better performance:

        @Override
        public int getCount() {
            return items.size();
        }

        @Override
        public Object getItem(int position) {
            return this.items.get(position);
        }

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

回答3:

You are missing getCount() method, look at this demo

I hope it will be helpful !

回答4:

 private ArrayList<Dept> items;
    private ArrayList<Dept> mOriginalValues;

    public DeptAdapter(Context context, int textViewResourceId, ArrayList<Dept> items) {
            super(context, textViewResourceId, items);
            this.items = items;
            this.mOriginalValues=items;  //add this line in your code
    }