Custom filtering in Android using ArrayAdapter

By | December 21, 2017
Questions:

I’m trying to filter my ListView which is populated with this ArrayAdapter:

package me.alxandr.android.mymir.adapters;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;

import me.alxandr.android.mymir.R;
import me.alxandr.android.mymir.model.Manga;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Filter;
import android.widget.SectionIndexer;
import android.widget.TextView;

public class MangaListAdapter extends ArrayAdapter<Manga> implements SectionIndexer
{
    public ArrayList<Manga> items;
    public ArrayList<Manga> filtered;
    private Context context;
    private HashMap<String, Integer> alphaIndexer;
    private String[] sections = new String[0];
    private Filter filter;
    private boolean enableSections;

    public MangaListAdapter(Context context, int textViewResourceId, ArrayList<Manga> items, boolean enableSections)
    {
        super(context, textViewResourceId, items);
        this.filtered = items;
        this.items = filtered;
        this.context = context;
        this.filter = new MangaNameFilter();
        this.enableSections = enableSections;

        if(enableSections)
        {
            alphaIndexer = new HashMap<String, Integer>();
            for(int i = items.size() - 1; i >= 0; i--)
            {
                Manga element = items.get(i);
                String firstChar = element.getName().substring(0, 1).toUpperCase();
                if(firstChar.charAt(0) > 'Z' || firstChar.charAt(0) < 'A')
                    firstChar = "@";

                alphaIndexer.put(firstChar, i);
            }

            Set<String> keys = alphaIndexer.keySet();
            Iterator<String> it = keys.iterator();
            ArrayList<String> keyList = new ArrayList<String>();
            while(it.hasNext())
                keyList.add(it.next());

            Collections.sort(keyList);
            sections = new String[keyList.size()];
            keyList.toArray(sections);
        }
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent)
    {
        View v = convertView;
        if(v == null)
        {
            LayoutInflater vi = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            v = vi.inflate(R.layout.mangarow, null);
        }

        Manga o = items.get(position);
        if(o != null)
        {
            TextView tt = (TextView) v.findViewById(R.id.MangaRow_MangaName);
            TextView bt = (TextView) v.findViewById(R.id.MangaRow_MangaExtra);
            if(tt != null)
                tt.setText(o.getName());
            if(bt != null)
                bt.setText(o.getLastUpdated() + " - " + o.getLatestChapter());

            if(enableSections && getSectionForPosition(position) != getSectionForPosition(position + 1))
            {
                TextView h = (TextView) v.findViewById(R.id.MangaRow_Header);
                h.setText(sections[getSectionForPosition(position)]);
                h.setVisibility(View.VISIBLE);
            }
            else
            {
                TextView h = (TextView) v.findViewById(R.id.MangaRow_Header);
                h.setVisibility(View.GONE);
            }
        }

        return v;
    }

    @Override
    public void notifyDataSetInvalidated()
    {
        if(enableSections)
        {
            for (int i = items.size() - 1; i >= 0; i--)
            {
                Manga element = items.get(i);
                String firstChar = element.getName().substring(0, 1).toUpperCase();
                if(firstChar.charAt(0) > 'Z' || firstChar.charAt(0) < 'A')
                    firstChar = "@";
                alphaIndexer.put(firstChar, i);
            }

            Set<String> keys = alphaIndexer.keySet();
            Iterator<String> it = keys.iterator();
            ArrayList<String> keyList = new ArrayList<String>();
            while (it.hasNext())
            {
                keyList.add(it.next());
            }

            Collections.sort(keyList);
            sections = new String[keyList.size()];
            keyList.toArray(sections);

            super.notifyDataSetInvalidated();
        }
    }

    public int getPositionForSection(int section)
    {
        if(!enableSections) return 0;
        String letter = sections[section];

        return alphaIndexer.get(letter);
    }

    public int getSectionForPosition(int position)
    {
        if(!enableSections) return 0;
        int prevIndex = 0;
        for(int i = 0; i < sections.length; i++)
        {
            if(getPositionForSection(i) > position && prevIndex <= position)
            {
                prevIndex = i;
                break;
            }
            prevIndex = i;
        }
        return prevIndex;
    }

    public Object[] getSections()
    {
        return sections;
    }

    @Override
    public Filter getFilter()
    {
        if(filter == null)
            filter = new MangaNameFilter();
        return filter;
    }

    private class MangaNameFilter extends Filter
    {

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            // NOTE: this function is *always* called from a background thread, and
            // not the UI thread.
            constraint = constraint.toString().toLowerCase();
            FilterResults result = new FilterResults();
            if(constraint != null && constraint.toString().length() > 0)
            {
                ArrayList<Manga> filt = new ArrayList<Manga>();
                ArrayList<Manga> lItems = new ArrayList<Manga>();
                synchronized (items)
                {
                    Collections.copy(lItems, items);
                }
                for(int i = 0, l = lItems.size(); i < l; i++)
                {
                    Manga m = lItems.get(i);
                    if(m.getName().toLowerCase().contains(constraint))
                        filt.add(m);
                }
                result.count = filt.size();
                result.values = filt;
            }
            else
            {
                synchronized(items)
                {
                    result.values = items;
                    result.count = items.size();
                }
            }
            return result;
        }

        @SuppressWarnings("unchecked")
        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            // NOTE: this function is *always* called from the UI thread.
            filtered = (ArrayList<Manga>)results.values;
            notifyDataSetChanged();
        }

    }
}

However, when I call filter(‘test’) on the filter nothing happens at all (or the background-thread is run, but the list isn’t filtered as far as the user conserns). How can I fix this?

Answers:

This fixed my problem. I’m not certain it’s the best solution, but it works. My project’s open-source, so feel free to use any of the code here should it prove usefull :-).

package me.alxandr.android.mymir.adapters;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;

import me.alxandr.android.mymir.R;
import me.alxandr.android.mymir.model.Manga;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Filter;
import android.widget.SectionIndexer;
import android.widget.TextView;

public class MangaListAdapter extends ArrayAdapter<Manga> implements SectionIndexer
{
    public ArrayList<Manga> items;
    public ArrayList<Manga> filtered;
    private Context context;
    private HashMap<String, Integer> alphaIndexer;
    private String[] sections = new String[0];
    private Filter filter;
    private boolean enableSections;

    public Manga getByPosition(int position)
    {
        return items.get(position);
    }

    public MangaListAdapter(Context context, int textViewResourceId, ArrayList<Manga> items, boolean enableSections)
    {
        super(context, textViewResourceId, items);
        this.filtered = items;
        this.items = ArrayList<Manga> items.clone();
        this.context = context;
        this.filter = new MangaNameFilter();
        this.enableSections = enableSections;

        if(enableSections)
        {
            alphaIndexer = new HashMap<String, Integer>();
            for(int i = items.size() - 1; i >= 0; i--)
            {
                Manga element = items.get(i);
                String firstChar = element.getName().substring(0, 1).toUpperCase();
                if(firstChar.charAt(0) > 'Z' || firstChar.charAt(0) < 'A')
                    firstChar = "@";

                alphaIndexer.put(firstChar, i);
            }

            Set<String> keys = alphaIndexer.keySet();
            Iterator<String> it = keys.iterator();
            ArrayList<String> keyList = new ArrayList<String>();
            while(it.hasNext())
                keyList.add(it.next());

            Collections.sort(keyList);
            sections = new String[keyList.size()];
            keyList.toArray(sections);
        }
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent)
    {
        View v = convertView;
        if(v == null)
        {
            LayoutInflater vi = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            v = vi.inflate(R.layout.mangarow, null);
        }

        Manga o = filtered.get(position);
        if(o != null)
        {
            TextView tt = (TextView) v.findViewById(R.id.MangaRow_MangaName);
            TextView bt = (TextView) v.findViewById(R.id.MangaRow_MangaExtra);
            if(tt != null)
                tt.setText(o.getName());
            if(bt != null)
                bt.setText(o.getLastUpdated() + " - " + o.getLatestChapter());

            if(enableSections && getSectionForPosition(position) != getSectionForPosition(position + 1))
            {
                TextView h = (TextView) v.findViewById(R.id.MangaRow_Header);
                h.setText(sections[getSectionForPosition(position)]);
                h.setVisibility(View.VISIBLE);
            }
            else
            {
                TextView h = (TextView) v.findViewById(R.id.MangaRow_Header);
                h.setVisibility(View.GONE);
            }
        }

        return v;
    }

    @Override
    public void notifyDataSetInvalidated()
    {
        if(enableSections)
        {
            for (int i = items.size() - 1; i >= 0; i--)
            {
                Manga element = items.get(i);
                String firstChar = element.getName().substring(0, 1).toUpperCase();
                if(firstChar.charAt(0) > 'Z' || firstChar.charAt(0) < 'A')
                    firstChar = "@";
                alphaIndexer.put(firstChar, i);
            }

            Set<String> keys = alphaIndexer.keySet();
            Iterator<String> it = keys.iterator();
            ArrayList<String> keyList = new ArrayList<String>();
            while (it.hasNext())
            {
                keyList.add(it.next());
            }

            Collections.sort(keyList);
            sections = new String[keyList.size()];
            keyList.toArray(sections);

            super.notifyDataSetInvalidated();
        }
    }

    public int getPositionForSection(int section)
    {
        if(!enableSections) return 0;
        String letter = sections[section];

        return alphaIndexer.get(letter);
    }

    public int getSectionForPosition(int position)
    {
        if(!enableSections) return 0;
        int prevIndex = 0;
        for(int i = 0; i < sections.length; i++)
        {
            if(getPositionForSection(i) > position && prevIndex <= position)
            {
                prevIndex = i;
                break;
            }
            prevIndex = i;
        }
        return prevIndex;
    }

    public Object[] getSections()
    {
        return sections;
    }

    @Override
    public Filter getFilter()
    {
        if(filter == null)
            filter = new MangaNameFilter();
        return filter;
    }

    private class MangaNameFilter extends Filter
    {

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            // NOTE: this function is *always* called from a background thread, and
            // not the UI thread.
            constraint = constraint.toString().toLowerCase();
            FilterResults result = new FilterResults();
            if(constraint != null && constraint.toString().length() > 0)
            {
                ArrayList<Manga> filt = new ArrayList<Manga>();
                ArrayList<Manga> lItems = new ArrayList<Manga>();
                synchronized (this)
                {
                    lItems.addAll(items);
                }
                for(int i = 0, l = lItems.size(); i < l; i++)
                {
                    Manga m = lItems.get(i);
                    if(m.getName().toLowerCase().contains(constraint))
                        filt.add(m);
                }
                result.count = filt.size();
                result.values = filt;
            }
            else
            {
                synchronized(this)
                {
                    result.values = items;
                    result.count = items.size();
                }
            }
            return result;
        }

        @SuppressWarnings("unchecked")
        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            // NOTE: this function is *always* called from the UI thread.
            filtered = (ArrayList<Manga>)results.values;
            notifyDataSetChanged();
            clear();
            for(int i = 0, l = filtered.size(); i < l; i++)
                add(filtered.get(i));
            notifyDataSetInvalidated();
        }

    }
}

Questions:
Answers:

I did not feel the need to do any of the above. Override toString() method of POJO like …

public String toString() {
    return this.getCallTitle() == null ? "" :      
     this.getCallTitle().toLowerCase();
}

TextWatcher is simply filtering and an easier way to.

adapter.getFilter().filter(chars.toString().toLowerCase());

Unless you have very custom filtering, this solution works.
Hope this benefits others.

Questions:
Answers:

I wrote this class which is basically a copy of ArrayAdapter with only a slight modification similar to Alxandr solution, but more elegant.

All I did, was pulling the filter-logic from the nested class ArrayAdapter.ArrayFilter to the ArrayAdapter-class to expose it (and allow the user to override it).

package com.example;

/* Copyright (C) 2006 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. */

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import android.content.Context;
import android.util.Log;
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.TextView;

/**
 * Slightly adopted ArrayAdapter. Basically a simple copy of ArrayAdapter with an extracted method filterObject() to
 * allow easy change of the filtering-behaviour.
 * 
 * A concrete BaseAdapter that is backed by an array of arbitrary objects. By default this class expects that the
 * provided resource id references a single TextView. If you want to use a more complex layout, use the constructors
 * that also takes a field id. That field id should reference a TextView in the larger layout resource.
 * 
 * <p>
 * However the TextView is referenced, it will be filled with the toString() of each object in the array. You can add
 * lists or arrays of custom objects. Override the toString() method of your objects to determine what text will be
 * displayed for the item in the list.
 * 
 * <p>
 * To use something other than TextViews for the array display, for instance, ImageViews, or to have some of data
 * besides toString() results fill the views, override {@link #getView(int, View, ViewGroup)} to return the type of view
 * you want.
 * 
 * @param <T> The class, this adapter should hold
 */
public class OGArrayAdapter<T> extends BaseAdapter implements Filterable {
    /**
     * Contains the list of objects that represent the data of this ArrayAdapter. The content of this list is referred
     * to as "the array" in the documentation.
     */
    private List<T> mObjects;

    /**
     * Lock used to modify the content of {@link #mObjects}. Any write operation performed on the array should be
     * synchronized on this lock. This lock is also used by the filter (see {@link #getFilter()} to make a synchronized
     * copy of the original array of data.
     */
    private final Object mLock = new Object();

    /**
     * The resource indicating what views to inflate to display the content of this array adapter.
     */
    private int mResource;

    /**
     * The resource indicating what views to inflate to display the content of this array adapter in a drop down widget.
     */
    private int mDropDownResource;

    /**
     * If the inflated resource is not a TextView, {@link #mFieldId} is used to find a TextView inside the inflated
     * views hierarchy. This field must contain the identifier that matches the one defined in the resource file.
     */
    private int mFieldId = 0;

    /**
     * Indicates whether or not {@link #notifyDataSetChanged()} must be called whenever {@link #mObjects} is modified.
     */
    private boolean mNotifyOnChange = true;

    private Context mContext;

    // A copy of the original mObjects array, initialized from and then used instead as soon as
    // the mFilter ArrayFilter is used. mObjects will then only contain the filtered values.
    private ArrayList<T> mOriginalValues;
    private OGArrayFilter mFilter;

    private LayoutInflater mInflater;

    /**
     * Constructor
     * 
     * @param context The current context.
     * @param textViewResourceId The resource ID for a layout file containing a TextView to use when instantiating
     *            views.
     */
    public OGArrayAdapter(Context context, int textViewResourceId) {
        init(context, textViewResourceId, 0, new ArrayList<T>());
    }

    /**
     * Constructor
     * 
     * @param context The current context.
     * @param resource The resource ID for a layout file containing a layout to use when instantiating views.
     * @param textViewResourceId The id of the TextView within the layout resource to be populated
     */
    public OGArrayAdapter(Context context, int resource, int textViewResourceId) {
        init(context, resource, textViewResourceId, new ArrayList<T>());
    }

    /**
     * Constructor
     * 
     * @param context The current context.
     * @param textViewResourceId The resource ID for a layout file containing a TextView to use when instantiating
     *            views.
     * @param objects The objects to represent in the ListView.
     */
    public OGArrayAdapter(Context context, int textViewResourceId, T[] objects) {
        init(context, textViewResourceId, 0, Arrays.asList(objects));
    }

    /**
     * Constructor
     * 
     * @param context The current context.
     * @param resource The resource ID for a layout file containing a layout to use when instantiating views.
     * @param textViewResourceId The id of the TextView within the layout resource to be populated
     * @param objects The objects to represent in the ListView.
     */
    public OGArrayAdapter(Context context, int resource, int textViewResourceId, T[] objects) {
        init(context, resource, textViewResourceId, Arrays.asList(objects));
    }

    /**
     * Constructor
     * 
     * @param context The current context.
     * @param textViewResourceId The resource ID for a layout file containing a TextView to use when instantiating
     *            views.
     * @param objects The objects to represent in the ListView.
     */
    public OGArrayAdapter(Context context, int textViewResourceId, List<T> objects) {
        init(context, textViewResourceId, 0, objects);
    }

    /**
     * Constructor
     * 
     * @param context The current context.
     * @param resource The resource ID for a layout file containing a layout to use when instantiating views.
     * @param textViewResourceId The id of the TextView within the layout resource to be populated
     * @param objects The objects to represent in the ListView.
     */
    public OGArrayAdapter(Context context, int resource, int textViewResourceId, List<T> objects) {
        init(context, resource, textViewResourceId, objects);
    }

    /**
     * Adds the specified object at the end of the array.
     * 
     * @param object The object to add at the end of the array.
     */
    public void add(T object) {
        synchronized (mLock) {
            if (mOriginalValues != null) {
                mOriginalValues.add(object);
            } else {
                mObjects.add(object);
            }
        }
        if (mNotifyOnChange)
            notifyDataSetChanged();
    }

    /**
     * Adds the specified Collection at the end of the array.
     * 
     * @param collection The Collection to add at the end of the array.
     */
    public void addAll(Collection<? extends T> collection) {
        synchronized (mLock) {
            if (mOriginalValues != null) {
                mOriginalValues.addAll(collection);
            } else {
                mObjects.addAll(collection);
            }
        }
        if (mNotifyOnChange)
            notifyDataSetChanged();
    }

    /**
     * Adds the specified items at the end of the array.
     * 
     * @param items The items to add at the end of the array.
     */
    public void addAll(T... items) {
        synchronized (mLock) {
            if (mOriginalValues != null) {
                Collections.addAll(mOriginalValues, items);
            } else {
                Collections.addAll(mObjects, items);
            }
        }
        if (mNotifyOnChange)
            notifyDataSetChanged();
    }

    /**
     * Inserts the specified object at the specified index in the array.
     * 
     * @param object The object to insert into the array.
     * @param index The index at which the object must be inserted.
     */
    public void insert(T object, int index) {
        synchronized (mLock) {
            if (mOriginalValues != null) {
                mOriginalValues.add(index, object);
            } else {
                mObjects.add(index, object);
            }
        }
        if (mNotifyOnChange)
            notifyDataSetChanged();
    }

    /**
     * Removes the specified object from the array.
     * 
     * @param object The object to remove.
     */
    public void remove(T object) {
        synchronized (mLock) {
            if (mOriginalValues != null) {
                mOriginalValues.remove(object);
            } else {
                mObjects.remove(object);
            }
        }
        if (mNotifyOnChange)
            notifyDataSetChanged();
    }

    /**
     * Remove all elements from the list.
     */
    public void clear() {
        synchronized (mLock) {
            if (mOriginalValues != null) {
                mOriginalValues.clear();
            } else {
                mObjects.clear();
            }
        }
        if (mNotifyOnChange)
            notifyDataSetChanged();
    }

    /**
     * Sorts the content of this adapter using the specified comparator.
     * 
     * @param comparator The comparator used to sort the objects contained in this adapter.
     */
    public void sort(Comparator<? super T> comparator) {
        synchronized (mLock) {
            if (mOriginalValues != null) {
                Collections.sort(mOriginalValues, comparator);
            } else {
                Collections.sort(mObjects, comparator);
            }
        }
        if (mNotifyOnChange)
            notifyDataSetChanged();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void notifyDataSetChanged() {
        super.notifyDataSetChanged();
        mNotifyOnChange = true;
    }

    /**
     * Control whether methods that change the list ({@link #add}, {@link #insert}, {@link #remove}, {@link #clear})
     * automatically call {@link #notifyDataSetChanged}. If set to false, caller must manually call
     * notifyDataSetChanged() to have the changes reflected in the attached view.
     * 
     * The default is true, and calling notifyDataSetChanged() resets the flag to true.
     * 
     * @param notifyOnChange if true, modifications to the list will automatically call {@link #notifyDataSetChanged}
     */
    public void setNotifyOnChange(boolean notifyOnChange) {
        mNotifyOnChange = notifyOnChange;
    }

    private void init(Context context, int resource, int textViewResourceId, List<T> objects) {
        mContext = context;
        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        mResource = mDropDownResource = resource;
        mObjects = objects;
        mFieldId = textViewResourceId;
    }

    /**
     * Returns the context associated with this array adapter. The context is used to create views from the resource
     * passed to the constructor.
     * 
     * @return The Context associated with this adapter.
     */
    public Context getContext() {
        return mContext;
    }

    /**
     * {@inheritDoc}
     */
    public int getCount() {
        return mObjects.size();
    }

    /**
     * {@inheritDoc}
     */
    public T getItem(int position) {
        return mObjects.get(position);
    }

    /**
     * Returns the position of the specified item in the array.
     * 
     * @param item The item to retrieve the position of.
     * 
     * @return The position of the specified item.
     */
    public int getPosition(T item) {
        return mObjects.indexOf(item);
    }

    /**
     * {@inheritDoc}
     */
    public long getItemId(int position) {
        return position;
    }

    /**
     * {@inheritDoc}
     */
    public View getView(int position, View convertView, ViewGroup parent) {
        return createViewFromResource(position, convertView, parent, mResource);
    }

    private View createViewFromResource(int position, View convertView, ViewGroup parent, int resource) {
        View view;
        TextView text;

        if (convertView == null) {
            view = mInflater.inflate(resource, parent, false);
        } else {
            view = convertView;
        }

        try {
            if (mFieldId == 0) {
                //  If no custom field is assigned, assume the whole resource is a TextView
                text = (TextView) view;
            } else {
                //  Otherwise, find the TextView field within the layout
                text = (TextView) view.findViewById(mFieldId);
            }
        } catch (ClassCastException e) {
            Log.e("ArrayAdapter", "You must supply a resource ID for a TextView");
            throw new IllegalStateException("ArrayAdapter requires the resource ID to be a TextView", e);
        }

        T item = getItem(position);
        if (item instanceof CharSequence) {
            text.setText((CharSequence) item);
        } else {
            text.setText(item.toString());
        }

        return view;
    }

    /**
     * <p>
     * Sets the layout resource to create the drop down views.
     * </p>
     * 
     * @param resource the layout resource defining the drop down views
     * @see #getDropDownView(int, android.view.View, android.view.ViewGroup)
     */
    public void setDropDownViewResource(int resource) {
        this.mDropDownResource = resource;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public View getDropDownView(int position, View convertView, ViewGroup parent) {
        return createViewFromResource(position, convertView, parent, mDropDownResource);
    }

    /**
     * Creates a new ArrayAdapter from external resources. The content of the array is obtained through
     * {@link android.content.res.Resources#getTextArray(int)}.
     * 
     * @param context The application's environment.
     * @param textArrayResId The identifier of the array to use as the data source.
     * @param textViewResId The identifier of the layout used to create views.
     * 
     * @return An ArrayAdapter<CharSequence>.
     */
    public static ArrayAdapter<CharSequence> createFromResource(Context context, int textArrayResId, int textViewResId) {
        CharSequence[] strings = context.getResources().getTextArray(textArrayResId);
        return new ArrayAdapter<CharSequence>(context, textViewResId, strings);
    }

    /**
     * {@inheritDoc}
     */
    public Filter getFilter() {
        if (mFilter == null) {
            mFilter = new OGArrayFilter();
        }
        return mFilter;
    }

    /**
     * Performs filtering on the provided object and returns true, if the object should be in the filtered collection,
     * or false if it shouldn't.
     * 
     * @param myObject The object to be inspected
     * @param constraint Constraint, that the object has to fulfil
     * @return true, if the object should be in the filteredResult, false otherwise
     */
    protected boolean filterObject(T myObject, String constraint) {
        final String valueText = myObject.toString().toLowerCase();

        // First match against the whole, non-splitted value
        if (valueText.startsWith(constraint)) {
            return true;
        } else {
            final String[] words = valueText.split(" ");
            final int wordCount = words.length;

            // Start at index 0, in case valueText starts with space(s)
            for (int k = 0; k < wordCount; k++) {
                if (words[k].startsWith(constraint)) {
                    return true;
                }
            }
        }

        // No match, so don't add to collection
        return false;
    }

    /**
     * <p>
     * An array filter constrains the content of the array adapter with a prefix. Each item that does not start with the
     * supplied prefix is removed from the list.
     * </p>
     */
    private class OGArrayFilter extends Filter {
        @Override
        protected FilterResults performFiltering(CharSequence prefix) {
            FilterResults results = new FilterResults();

            if (mOriginalValues == null) {
                synchronized (mLock) {
                    mOriginalValues = new ArrayList<T>(mObjects);
                }
            }

            if (prefix == null || prefix.length() == 0) {
                ArrayList<T> list;
                synchronized (mLock) {
                    list = new ArrayList<T>(mOriginalValues);
                }
                results.values = list;
                results.count = list.size();
            } else {
                String prefixString = prefix.toString().toLowerCase();

                ArrayList<T> values;
                synchronized (mLock) {
                    values = new ArrayList<T>(mOriginalValues);
                }

                final int count = values.size();
                final ArrayList<T> newValues = new ArrayList<T>();

                for (int i = 0; i < count; i++) {
                    final T value = values.get(i);
                    if (filterObject(value, prefixString)) {
                        newValues.add(value);
                    }
                }

                results.values = newValues;
                results.count = newValues.size();
            }

            return results;
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            //noinspection unchecked
            mObjects = (List<T>) results.values;
            if (results.count > 0) {
                notifyDataSetChanged();
            } else {
                notifyDataSetInvalidated();
            }
        }
    }
}

The benefit of this solution is it’s beauty at application, just by overriding the filterObject-method which was pulled out from the ArrayAdapter.ArrayFilter-class into the ArrayAdapter:

public class MyAdapter extends OGArrayAdapter<OGScene> {
    // Do the rest of your adapter

    @Override
    protected boolean filterObject(OGScene myObject, String constraint) {
        // If true, the object will be in the list, if false, it will be filtered.
        // Do your own filtering with myObject as you desire
        return myObject.fulfillsConstraint(constraint);
    }
}

Questions:
Answers:

The best way I found to to filter ArrayAdapter is to create my own filter class:

private class MyFilter extends Filter

then in that function create the new object array to display after the filter (you can find good implementation in the source code of class ArrayAdapter)

@Override
protected FilterResults performFiltering(CharSequence prefix)

now the trick is in this method

@Override
protected void publishResults(CharSequence constraint, FilterResults results)

when you use the Array adapter you can’t do this:

myAdapterData = results.values

since then you disconnect your data from the super data, you must do this to keep your reference to the super original data array:

data.clear();
data.addAll((List<YourType>) results.values);

and then override

getFilter()

in your adapter, for example:

@Override
public Filter getFilter() {
    if (filter == null) {
        filter = new MyFilter();
    }
    return filter;
}

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