RecyclerAdapter.java

package monakhv.android.samlib.adapter;

import android.support.v7.widget.RecyclerView;
import monakhv.samlib.db.entity.Author;
import monakhv.samlib.log.Log;

import java.util.List;

/*
 * Copyright 2015  Dmitry Monakhov
 *
 * 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.
 *
 * 23.07.15.
 */
public abstract class RecyclerAdapter<T, VH extends android.support.v7.widget.RecyclerView.ViewHolder> extends RecyclerView.Adapter<VH> {
    private static final String DEBUG_TAG = "RecyclerAdapter";

    public interface CallBack {
        void makeNewFlip(Author a);

        void refresh();
    }

    protected List<T> mData;
    protected CallBack mCallBack;

    public RecyclerAdapter(CallBack callBack) {
        mCallBack = callBack;
    }


    public void setData(List<T> data) {
        mData = data;
        notifyDataSetChanged();
    }

    @Override
    public int getItemCount() {
        if (mData == null) {
            return 0;
        } else {
            return mData.size();
        }
    }

    public static final int NOT_SELECTED = -1;
    private int selected = NOT_SELECTED;

    /**
     * Change selection position
     * make notification by default
     *
     * @param position new selected item position
     */
    public void toggleSelection(int position) {
        toggleSelection(position, true);
    }

    /**
     * Change selected element position
     *
     * @param position new selection position
     * @param notified whether make change item notification or not
     */
    public void toggleSelection(int position, boolean notified) {
        Log.d(DEBUG_TAG,"toggleSelection: "+position+"  "+notified);
        if (position == selected) {
            return;//selection is not changed - ignore it
        }

        int old_selection = selected;//preserve old selection position
        selected = position;//new position

        if (old_selection != NOT_SELECTED && notified) {
            notifyItemChanged(old_selection);//clean up old selection
        }
        if (selected != NOT_SELECTED && notified) {
            notifyItemChanged(selected);//make new selection
        }
    }

    public void cleanSelection() {
        toggleSelection(NOT_SELECTED);
    }


    public int getSelectedPosition() {
        return selected;
    }

    public T getSelected() {
        int pos = getSelectedPosition();
        if (pos == NOT_SELECTED) {
            Log.e(DEBUG_TAG, "getSelected: position is NOT_SELECTED");
            return null;
        }

        if (pos < mData.size()) {
            return mData.get(pos);
        } else {
            return null;
        }

    }


}