Adding a locale picker with two-step selection: language, then region.

/*

 * Copyright (C) 2015 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.android.internal.app;

import com.android.internal.R;

import android.app.ListFragment;

import android.content.Context;

import android.content.res.Resources;

import android.os.Bundle;

import android.util.ArrayMap;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ArrayAdapter;

import android.widget.ListView;

import android.widget.TextView;

import java.text.Collator;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.HashSet;

import java.util.List;

import java.util.Locale;

import java.util.Map;

class LocaleAdapter extends ArrayAdapter<LocalePicker.LocaleInfo> {

    final private Map<String, LocalePicker.LocaleInfo> mLevelOne = new ArrayMap<>();

    final private Map<String, HashSet<LocalePicker.LocaleInfo>> mLevelTwo = new ArrayMap<>();

    final private LayoutInflater mInflater;

    final static class LocaleAwareComparator implements Comparator<LocalePicker.LocaleInfo> {

        private final Collator mCollator;

        public LocaleAwareComparator(Locale sortLocale) {

            mCollator = Collator.getInstance(sortLocale);

        }

        @Override

        public int compare(LocalePicker.LocaleInfo lhs, LocalePicker.LocaleInfo rhs) {

            return mCollator.compare(lhs.getLabel(), rhs.getLabel());

        }

    }

    static List<Locale> getCuratedLocaleList(Context context) {

        final Resources resources = context.getResources();

        final String[] supportedLocaleCodes = resources.getStringArray(R.array.supported_locales);

        final ArrayList<Locale> result = new ArrayList<>(supportedLocaleCodes.length);

        for (String localeId : supportedLocaleCodes) {

            Locale locale = Locale.forLanguageTag(localeId);

            if (!locale.getCountry().isEmpty()) {

                result.add(Locale.forLanguageTag(localeId));

            }

        }

        return result;

    }

    public LocaleAdapter(Context context) {

        this(context, getCuratedLocaleList(context));

    }

    static Locale getBaseLocale(Locale locale) {

        return new Locale.Builder()

                .setLocale(locale)

                .setRegion("")

                .build();

    }

    // There is no good API available for this, not even in ICU.

    // We can revisit this if we get some ICU support later

    //

    // There are currently several tickets requesting this feature:

    // * ICU needs to provide an easy way to titlecase only one first letter

    //   http://bugs.icu-project.org/trac/ticket/11729

    // * Add "initial case"

    //    http://bugs.icu-project.org/trac/ticket/8394

    // * Add code for initialCase, toTitlecase don't modify after Lt,

    //   avoid 49Ers, low-level language-specific casing

    //   http://bugs.icu-project.org/trac/ticket/10410

    // * BreakIterator.getFirstInstance: Often you need to titlecase just the first

    //   word, and leave the rest of the string alone.  (closed as duplicate)

    //   http://bugs.icu-project.org/trac/ticket/8946

    //

    // A (clunky) option with the current ICU API is:

    //   BreakIterator breakIterator = BreakIterator.getSentenceInstance(locale);

    //   String result = UCharacter.toTitleCase(locale,

    //       source, breakIterator, UCharacter.TITLECASE_NO_LOWERCASE);

    // That also means creating BreakIteratos for each locale. Expensive...

    private static String toTitleCase(String s, Locale locale) {

        if (s.length() == 0) {

            return s;

        }

        final int firstCodePointLen = s.offsetByCodePoints(0, 1);

        return s.substring(0, firstCodePointLen).toUpperCase(locale)

                + s.substring(firstCodePointLen);

    }

    public LocaleAdapter(Context context, List<Locale> locales) {

        super(context, R.layout.locale_picker_item, R.id.locale);

        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        for (Locale locale : locales) {

            Locale baseLocale = getBaseLocale(locale);

            String language = baseLocale.toLanguageTag();

            if (!mLevelOne.containsKey(language)) {

                String label = toTitleCase(baseLocale.getDisplayName(baseLocale), baseLocale);

                mLevelOne.put(language, new LocalePicker.LocaleInfo(label, baseLocale));

            }

            final HashSet<LocalePicker.LocaleInfo> subLocales;

            if (mLevelTwo.containsKey(language)) {

                subLocales = mLevelTwo.get(language);

            } else {

                subLocales = new HashSet<>();

                mLevelTwo.put(language, subLocales);

            }

            String label = locale.getDisplayCountry(locale);

            subLocales.add(new LocalePicker.LocaleInfo(label, locale));

        }

        setAdapterLevel(null);

    }

    public void setAdapterLevel(String parentLocale) {

        this.clear();

        if (parentLocale == null) {

            this.addAll(mLevelOne.values());

        } else {

            this.addAll(mLevelTwo.get(parentLocale));

        }

        Locale sortLocale = (parentLocale == null)

                ? Locale.getDefault()

                : Locale.forLanguageTag(parentLocale);

        LocaleAwareComparator comparator = new LocaleAwareComparator(sortLocale);

        this.sort(comparator);

        this.notifyDataSetChanged();

    }

    @Override

    public View getView(int position, View convertView, ViewGroup parent) {

        View view;

        TextView text;

        if (convertView == null) {

            view = mInflater.inflate(R.layout.locale_picker_item, parent, false);

            text = (TextView) view.findViewById(R.id.locale);

            view.setTag(text);

        } else {

            view = convertView;

            text = (TextView) view.getTag();

        }

        LocalePicker.LocaleInfo item = getItem(position);

        text.setText(item.getLabel());

        text.setTextLocale(item.getLocale());

        return view;

    }

}

public class LocalePickerWithRegion extends ListFragment {

    private static final int LIST_MODE_LANGUAGE = 0;

    private static final int LIST_MODE_COUNTRY = 1;

    private LocaleAdapter mAdapter;

    private int mDisplayMode = LIST_MODE_LANGUAGE;

    public static interface LocaleSelectionListener {

        // You can add any argument if you really need it...

        public void onLocaleSelected(Locale locale);

    }

    private LocaleSelectionListener mListener = null;

    @Override

    public void onActivityCreated(final Bundle savedInstanceState) {

        super.onActivityCreated(savedInstanceState);

        mAdapter = new LocaleAdapter(getContext());

        mAdapter.setAdapterLevel(null);

        setListAdapter(mAdapter);

    }

    public void setLocaleSelectionListener(LocaleSelectionListener listener) {

        mListener = listener;

    }

    @Override

    public void onResume() {

        super.onResume();

        getListView().requestFocus();

    }

    /**

     * Each listener needs to call {@link LocalePicker.updateLocale(Locale)} to actually

     * change the locale.

     * <p/>

     * We don't call {@link LocalePicker.updateLocale(Locale)} automatically, as it halts

     * the system for a moment and some callers won't want it.

     */

    @Override

    public void onListItemClick(ListView l, View v, int position, long id) {

        final Locale locale = ((LocalePicker.LocaleInfo) getListAdapter().getItem(position)).locale;

        // TODO: handle the back buttons to return to the language list

        if (mDisplayMode == LIST_MODE_LANGUAGE) {

            mDisplayMode = LIST_MODE_COUNTRY;

            mAdapter.setAdapterLevel(locale.toLanguageTag());

            return;

        }

        if (mListener != null) {

            mListener.onLocaleSelected(locale);

        }

    }

}

  <java-symbol type="array" name="sim_colors" />

  <java-symbol type="array" name="special_locale_codes" />

  <java-symbol type="array" name="special_locale_names" />

  <java-symbol type="array" name="supported_locales" />

  <java-symbol type="array" name="config_cdma_dun_supported_types" />

  <java-symbol type="array" name="config_disabledUntilUsedPreinstalledImes" />

  <java-symbol type="array" name="config_disabledUntilUsedPreinstalledCarrierApps" />