Audinaut-subsonic-app-android/app/src/main/java/net/nullsum/audinaut/adapter/ExpandableSectionAdapter.java

/*
  This file is part of Subsonic.
    Subsonic is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
    Subsonic is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU General Public License for more details.
    You should have received a copy of the GNU General Public License
    along with Subsonic. If not, see <http://www.gnu.org/licenses/>.
    Copyright 2015 (C) Scott Jackson
*/

package net.nullsum.audinaut.adapter;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import net.nullsum.audinaut.R;
import net.nullsum.audinaut.util.DrawableTint;
import net.nullsum.audinaut.view.BasicHeaderView;
import net.nullsum.audinaut.view.UpdateView;

import java.util.ArrayList;
import java.util.List;

abstract class ExpandableSectionAdapter<T> extends SectionAdapter<T> {
    private static final int DEFAULT_VISIBLE = 4;
    private static final int EXPAND_TOGGLE = R.attr.select_server;
    private static final int COLLAPSE_TOGGLE = R.attr.select_tabs;

    private List<List<T>> sectionsExtras;

    ExpandableSectionAdapter() {
    }

    void init(Context context, List<String> headers, List<List<T>> fullSections, List<Integer> sectionsDefaultVisible) {
        this.context = context;
        this.headers = headers;
        if (sectionsDefaultVisible == null) {
            sectionsDefaultVisible = new ArrayList<>(fullSections.size());
            for (int i = 0; i < fullSections.size(); i++) {
                sectionsDefaultVisible.add(DEFAULT_VISIBLE);
            }
        }

        this.sections = new ArrayList<>();
        this.sectionsExtras = new ArrayList<>();
        int i = 0;
        for (List<T> fullSection : fullSections) {
            List<T> visibleSection = new ArrayList<>();

            Integer defaultVisible = sectionsDefaultVisible.get(i);
            if (defaultVisible == null || defaultVisible >= fullSection.size()) {
                visibleSection.addAll(fullSection);
                this.sectionsExtras.add(null);
            } else {
                visibleSection.addAll(fullSection.subList(0, defaultVisible));
                this.sectionsExtras.add(fullSection.subList(defaultVisible, fullSection.size()));
            }
            this.sections.add(visibleSection);

            i++;
        }
    }

    @Override
    public UpdateView.UpdateViewHolder onCreateHeaderHolder(ViewGroup parent) {
        return new UpdateView.UpdateViewHolder(new BasicHeaderView(context, R.layout.expandable_header));
    }

    @Override
    public void onBindHeaderHolder(UpdateView.UpdateViewHolder holder, String header, final int sectionIndex) {
        UpdateView view = holder.getUpdateView();
        ImageView toggleSelectionView = view.findViewById(R.id.item_select);

        List<T> visibleSelection = sections.get(sectionIndex);
        List<T> sectionExtras = sectionsExtras.get(sectionIndex);

        if (sectionExtras != null && !sectionExtras.isEmpty()) {
            toggleSelectionView.setVisibility(View.VISIBLE);
            toggleSelectionView.setOnClickListener(v -> {
                List<T> visibleSelection1 = sections.get(sectionIndex);
                List<T> sectionExtras1 = sectionsExtras.get(sectionIndex);

                // Update icon
                int selectToggleAttr;
                if (!visibleSelection1.contains(sectionExtras1.get(0))) {
                    selectToggleAttr = COLLAPSE_TOGGLE;

                    // Update how many are displayed
                    int lastIndex = getItemPosition(visibleSelection1.get(visibleSelection1.size() - 1));
                    visibleSelection1.addAll(sectionExtras1);
                    notifyItemRangeInserted(lastIndex, sectionExtras1.size());
                } else {
                    selectToggleAttr = EXPAND_TOGGLE;

                    // Update how many are displayed
                    visibleSelection1.removeAll(sectionExtras1);
                    int lastIndex = getItemPosition(visibleSelection1.get(visibleSelection1.size() - 1));
                    notifyItemRangeRemoved(lastIndex, sectionExtras1.size());
                }

                ((ImageView) v).setImageResource(DrawableTint.getDrawableRes(context, selectToggleAttr));
            });

            int selectToggleAttr;
            if (!visibleSelection.contains(sectionExtras.get(0))) {
                selectToggleAttr = EXPAND_TOGGLE;
            } else {
                selectToggleAttr = COLLAPSE_TOGGLE;
            }

            toggleSelectionView.setImageResource(DrawableTint.getDrawableRes(context, selectToggleAttr));
        } else {
            toggleSelectionView.setVisibility(View.GONE);
        }

        if (view != null) {
            view.setObject(header);
        }
    }
}