Simple ListView page indicator for use with ViewPagerIndicator

ListPageIndicator.java

import android.content.Context;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.AttributeSet;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import com.viewpagerindicator.PageIndicator;

import java.util.ArrayList;

public class ListPageIndicator extends ListView implements PageIndicator, OnItemClickListener {

    private static final CharSequence EMPTY_TITLE = "";

    private Context context;
    private ViewPager pager;
    private OnPageChangeListener listener;

    private ArrayList<CharSequence> titles;
    private int selectedIndex;

    public ListPageIndicator(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.context = context;
        setChoiceMode(CHOICE_MODE_SINGLE);
        setOnItemClickListener(this);
    }

    @Override
    public void setViewPager(ViewPager pager) {
        if (this.pager == pager) {
            return;
        }
        if (this.pager != null) {
            this.pager.setOnPageChangeListener(null);
        }
        final PagerAdapter adapter = pager.getAdapter();
        if (adapter == null) {
            throw new IllegalStateException("ViewPager does not have adapter instance.");
        }
        this.pager = pager;
        pager.setOnPageChangeListener(this);
        notifyDataSetChanged();
    }

    @Override
    public void setViewPager(ViewPager pager, int initialPosition) {
        setViewPager(pager);
        setCurrentItem(initialPosition);
    }

    @Override
    public void setCurrentItem(int position) {
        if (pager == null) {
            throw new IllegalStateException("ViewPager has not been bound.");
        }
        selectedIndex = position;
        pager.setCurrentItem(selectedIndex);

        setItemChecked(position, true);
    }

    @Override
    public void notifyDataSetChanged() {
        titles = new ArrayList<CharSequence>();
        PagerAdapter pagerAdapter = pager.getAdapter();
        int count = pagerAdapter.getCount();
        for (int i = 0; i < count; i++) {
            CharSequence title = pagerAdapter.getPageTitle(i);
            if (title == null) {
                title = EMPTY_TITLE;
            }
            titles.add(title);
        }
        if (selectedIndex > count) {
            selectedIndex = count - 1;
        }
        setData();
        setCurrentItem(selectedIndex);
    }

    private void setData() {
        setAdapter(new ArrayAdapter<CharSequence>(context, android.R.layout.simple_list_item_activated_1, titles));
    }

    @Override
    public void setOnPageChangeListener(OnPageChangeListener listener) {
        this.listener = listener;
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
        if (listener != null) {
            listener.onPageScrolled(position, positionOffset, positionOffsetPixels);
        }
    }

    @Override
    public void onPageSelected(int position) {
        setCurrentItem(position);
        if (listener != null) {
            listener.onPageSelected(position);
        }
    }

    @Override
    public void onPageScrollStateChanged(int i) {
        if (listener != null) {
            listener.onPageScrollStateChanged(i);
        }
    }

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
        setCurrentItem(i);
    }

}