Circular (or infinite) listview with ArrayAdapter

Question

I want my listview to repeat all rows after scrolling to the end, and so on. This is called infinite or circular, and you can find ways to implement it but none of these seems to work for my adapter. I tried this approach: How to create a closed (circular) ListView? but my app crashes when i put

    @Override
    public int getCount()
    {
        return Integer.MAX_VALUE;
    }

Also, getItem doesent seem to "play along" with my adapter

    @Override
    public T getItem(int position) 
    {
        return objects[position % objects.length];
    }

Is there a way to implement something similar for my adapter? here's the code:

    public class EntryAdapter extends ArrayAdapter<Item> {
private ArrayList<Item> items;
private Context fontcontext;
private LayoutInflater vi;


public EntryAdapter(Context context, ArrayList<Item> items) {
    super(context,0, items);
    fontcontext = context;
    this.items = items;
    vi = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

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

    final Item i = items.get(position);
    if (i != null) {
       if(i.isSection()){
            SectionItem si = (SectionItem)i;
            v = vi.inflate(R.layout.list_item_section, null);

            v.setOnClickListener(null);
            v.setOnLongClickListener(null);
            v.setLongClickable(false);

            final TextView sectionView = (TextView) v.findViewById(R.id.list_item_section_text);
            sectionView.setText(si.getTitle());
            Typeface faceT = Typeface.createFromAsset(fontcontext.getAssets(),"fonts/Walkwayrounded.ttf");
            sectionView.setTypeface(faceT);
            final TextView conditionView = (TextView) v.findViewById(R.id.textViewn);
            conditionView.setText(si.getCondition());
            Typeface faceC = Typeface.createFromAsset(fontcontext.getAssets(),"fonts/Walkwayrounded.ttf");
            conditionView.setTypeface(faceC);

        }else{
            EntryItem ei = (EntryItem)i;
            v = vi.inflate(R.layout.list_item_entry, null);
            final TextView title = (TextView)v.findViewById(R.id.list_item_entry_title);
            final TextView subtitle = (TextView)v.findViewById(R.id.list_item_entry_summary);


            if (title != null) 
                title.setText(ei.title);
            if(subtitle != null)
                subtitle.setText(ei.subtitle);
        }
    }
    return v;
}

    }

Any kind of approach to solve the problem will be appreciated!

Answer 1

It looks like your main issue is how you are referencing the items. You can't use items.get(position) because position is going to overflow. Try adding these methods to your adapter:

@Override
public int getCount() {
    return Integer.MAX_VALUE;
}

@Override
public Item getItem(int position) {
    return items.get(position % items.size());
}

And replace

final Item i = items.get(position); 

with

final Item i = getItem(position);

Answer 2

First, you should use a more effective way to draw the list items.

The Android Developer Resources site provides an "API Demos" SDK that you can download. There are a ton of Samples and recipes for different ways to work with the OS. One is created specifically for handling lists that contain either/both thousands of entries or memory hogging images -- called EfficientAdapter which extends the BaseAdapter class, allowing you to recycle the Views during the getView callback instead of inflating a new xml layout.

I found it under the src.com.example.apis.view

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.view;

import android.app.ListActivity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import android.widget.ImageView;
import android.graphics.BitmapFactory;
import android.graphics.Bitmap;
import com.example.android.apis.R;

/**
 * Demonstrates how to write an efficient list adapter. The adapter used in this example binds
 * to an ImageView and to a TextView for each row in the list.
 *
 * To work efficiently the adapter implemented here uses two techniques:
 * - It reuses the convertView passed to getView() to avoid inflating View when it is not necessary
 * - It uses the ViewHolder pattern to avoid calling findViewById() when it is not necessary
 *
 * The ViewHolder pattern consists in storing a data structure in the tag of the view returned by
 * getView(). This data structures contains references to the views we want to bind data to, thus
 * avoiding calls to findViewById() every time getView() is invoked.
 */
public class List14 extends ListActivity {

    private static class EfficientAdapter extends BaseAdapter {
        private LayoutInflater mInflater;
        private Bitmap mIcon1;
        private Bitmap mIcon2;

        public EfficientAdapter(Context context) {
            // Cache the LayoutInflate to avoid asking for a new one each time.
            mInflater = LayoutInflater.from(context);

            // Icons bound to the rows.
            mIcon1 = BitmapFactory.decodeResource(context.getResources(), R.drawable.icon48x48_1);
            mIcon2 = BitmapFactory.decodeResource(context.getResources(), R.drawable.icon48x48_2);
        }

        /**
         * The number of items in the list is determined by the number of speeches
         * in our array.
         *
         * @see android.widget.ListAdapter#getCount()
         */
        public int getCount() {
            return DATA.length;
        }

        /**
         * Since the data comes from an array, just returning the index is
         * sufficent to get at the data. If we were using a more complex data
         * structure, we would return whatever object represents one row in the
         * list.
         *
         * @see android.widget.ListAdapter#getItem(int)
         */
        public Object getItem(int position) {
            return position;
        }

        /**
         * Use the array index as a unique id.
         *
         * @see android.widget.ListAdapter#getItemId(int)
         */
        public long getItemId(int position) {
            return position;
        }

        /**
         * Make a view to hold each row.
         *
         * @see android.widget.ListAdapter#getView(int, android.view.View,
         *      android.view.ViewGroup)
         */
        public View getView(int position, View convertView, ViewGroup parent) {
            // A ViewHolder keeps references to children views to avoid unneccessary calls
            // to findViewById() on each row.
            ViewHolder holder;

            // When convertView is not null, we can reuse it directly, there is no need
            // to reinflate it. We only inflate a new View when the convertView supplied
            // by ListView is null.
            if (convertView == null) {
                convertView = mInflater.inflate(R.layout.list_item_icon_text, null);

                // Creates a ViewHolder and store references to the two children views
                // we want to bind data to.
                holder = new ViewHolder();
                holder.text = (TextView) convertView.findViewById(R.id.text);
                holder.icon = (ImageView) convertView.findViewById(R.id.icon);

                convertView.setTag(holder);
            } else {
                // Get the ViewHolder back to get fast access to the TextView
                // and the ImageView.
                holder = (ViewHolder) convertView.getTag();
            }

            // Bind the data efficiently with the holder.
            holder.text.setText(DATA[position]);
            holder.icon.setImageBitmap((position & 1) == 1 ? mIcon1 : mIcon2);

            return convertView;
        }

        static class ViewHolder {
            TextView text;
            ImageView icon;
        }
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setListAdapter(new EfficientAdapter(this));
    }

    private static final String[] DATA = Cheeses.sCheeseStrings;
}