MonthHolder.java

package io.github.memfis19.cadar.internal.ui.list.adapter.holder;

import android.os.Build;
import android.os.Handler;
import android.support.v7.widget.RecyclerView;
import android.text.Spannable;
import android.text.SpannableString;
import android.text.format.DateFormat;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

import com.squareup.picasso.Callback;
import com.squareup.picasso.Picasso;

import java.util.Calendar;

import io.github.memfis19.cadar.R;
import io.github.memfis19.cadar.internal.ui.list.adapter.decorator.MonthDecorator;
import io.github.memfis19.cadar.internal.ui.list.adapter.decorator.factory.MonthDecoratorFactory;

/**
 * Created by memfis on 9/5/16.
 */
public class MonthHolder extends ListHolder {

    private final String DATE_FORMAT = "MMMM yyyy";

    private TextView monthTitle;
    private ImageView monthBackground;

    private Handler backgroundHandler;
    private Handler uiHandler;

    private RecyclerView recyclerView;
    private View itemView;

    private RecyclerView.OnScrollListener attachedScrollListener;

    private MonthDecorator monthDecorator;

    private RecyclerView.OnScrollListener scrollListener = new RecyclerView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);
        }

        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            monthBackground.scrollBy(dx, (-1) * (dy / 10));
        }
    };

    public MonthHolder(RecyclerView recyclerView,
                       View itemView,
                       Handler backgroundHandler,
                       Handler uiHandler,
                       MonthDecoratorFactory monthDecoratorFactory) {
        super(itemView);

        this.itemView = itemView;
        this.backgroundHandler = backgroundHandler;
        this.uiHandler = uiHandler;
        this.recyclerView = recyclerView;

        if (monthDecoratorFactory != null) {
            monthDecorator = monthDecoratorFactory.createMonthDecorator(itemView);
        } else {
            monthTitle = (TextView) itemView.findViewById(R.id.month_label);
            monthBackground = (ImageView) itemView.findViewById(R.id.month_background);
        }
    }

    public void bindView(final Calendar month) {
        if (monthDecorator != null) {
            attachedScrollListener = monthDecorator.getScrollListener();
            recyclerView.addOnScrollListener(attachedScrollListener);

            monthDecorator.onBindMonthView(itemView, month);
        } else {
            attachedScrollListener = getScrollListener();
            recyclerView.addOnScrollListener(attachedScrollListener);

            monthBackground.setImageDrawable(null);
            backgroundHandler.post(new Runnable() {
                @Override
                public void run() {
                    final Spannable date = new SpannableString(DateFormat.format(DATE_FORMAT, month.getTime()).toString());

                    final int backgroundId = getBackgroundId(month.get(Calendar.MONTH));
                    uiHandler.post(new Runnable() {
                        @Override
                        public void run() {
                            monthTitle.setText(date);

                            Picasso.with(monthTitle.getContext().getApplicationContext()).load(backgroundId).into(monthBackground, new Callback() {
                                @Override
                                public void onSuccess() {
                                    if (Build.VERSION.SDK_INT > 13) {
                                        monthBackground.setScrollX(0);
                                        monthBackground.setScrollY(0);
                                    }
                                }

                                @Override
                                public void onError() {

                                }
                            });
                        }
                    });
                }
            });
        }
    }

    public void detach() {
        if (monthBackground != null) {
            recyclerView.removeOnScrollListener(attachedScrollListener);
        }
    }

    private RecyclerView.OnScrollListener getScrollListener() {
        return scrollListener;
    }

    private int getBackgroundId(int month) {
        int backgroundId = R.drawable.bkg_12_december;

        if (month == Calendar.JANUARY) {
            backgroundId = R.drawable.bkg_01_january;
        } else if (month == Calendar.FEBRUARY) {
            backgroundId = R.drawable.bkg_02_february;
        } else if (month == Calendar.MARCH) {
            backgroundId = R.drawable.bkg_03_march;
        } else if (month == Calendar.APRIL) {
            backgroundId = R.drawable.bkg_04_april;
        } else if (month == Calendar.MAY) {
            backgroundId = R.drawable.bkg_05_may;
        } else if (month == Calendar.JUNE) {
            backgroundId = R.drawable.bkg_06_june;
        } else if (month == Calendar.JULY) {
            backgroundId = R.drawable.bkg_07_july;
        } else if (month == Calendar.AUGUST) {
            backgroundId = R.drawable.bkg_08_august;
        } else if (month == Calendar.SEPTEMBER) {
            backgroundId = R.drawable.bkg_09_september;
        } else if (month == Calendar.OCTOBER) {
            backgroundId = R.drawable.bkg_10_october;
        } else if (month == Calendar.NOVEMBER) {
            backgroundId = R.drawable.bkg_11_november;
        }

        return backgroundId;
    }
}