Eu estou tentando implementar um getFilter () em um adaptador base para filtrar os resultados da pesquisa em uma lista. Existe algum exemplo de como implementar um getFilter ()?

MainActivity.java

   final AppInfoAdapter adapter = new AppInfoAdapter(this, Utilities.getSystemFilteredApplication(this), getPackageManager());


        public void onTextChanged(CharSequence s, int start, int before,
                int count) {
           adapter.getFilter().filter(s); //Filter from my adapter
           adapter.notifyDataSetChanged(); //Update my view
        }

AppInfoAdapter.java

package com.example.permission;

import java.util.List;

import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.ImageView;
import android.widget.TextView;

public class AppInfoAdapter extends BaseAdapter implements Filterable{
    private Context mContext;
    private List mListAppInfo;
    PackageManager mPackManager;

    public AppInfoAdapter(Context c, List list, PackageManager pm) {
        mContext = c;
        mListAppInfo = list;
        mPackManager = pm;
    }

    public int getCount() {
        return mListAppInfo.size();
    }


    public Object getItem(int position) {
        return mListAppInfo.get(position);
    }


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

    public View getView(int position, View convertView, ViewGroup parent) {
        // get the selected entry
        ApplicationInfo entry = (ApplicationInfo) mListAppInfo.get(position);

        // reference to convertView
        View v = convertView;

        // inflate new layout if null
        if(v == null) {
            LayoutInflater inflater = LayoutInflater.from(mContext);
            v = inflater.inflate(R.layout.layout_appinfo, null);
        }

        // load controls from layout resources
        ImageView ivAppIcon = (ImageView)v.findViewById(R.id.ivIcon);
        TextView tvAppName = (TextView)v.findViewById(R.id.tvName);
        TextView tvPkgName = (TextView)v.findViewById(R.id.tvPack);

        // set data to display
        ivAppIcon.setImageDrawable(entry.loadIcon(mPackManager));
        tvAppName.setText(entry.loadLabel(mPackManager));
        tvPkgName.setText(entry.packageName);

        // return view
        return v;
    }

    public Filter getFilter() {
        // TODO Auto-generated method stub
        return null;
    }


}

EDIT: Editado o código e adicionado AppInfoAdapter.java