Section.java

package com.anthony.rvhelper.section;

import android.content.Context;
import android.view.View;

import com.anthony.rvhelper.base.ViewHolder;


/**
 * Created by Anthony on 2016/8/17.
 * Class Note:
 *  Abstract Section used by SectionRVAdapter.
 */
public abstract class Section {

    public enum State { LOADING, LOADED, FAILED}

    private State state = State.LOADED;

    boolean visible = true;

    boolean hasHeader = false;
    boolean hasFooter = false;

    Integer headerResourceId;
    Integer footerResourceId;

    int itemResourceId;

    private Integer loadingResourceId;
    private Integer failedResourceId;

    /**
     * Package-level constructor
     */
    Section() {

    }

    /**
     * Create a Section object with loading/failed states but no header and footer
     * @param itemResourceId layout resource for its items
     * @param loadingResourceId layout resource for its loading state
     * @param failedResourceId layout resource for its failed state
     */
    public Section(int itemResourceId, int loadingResourceId, int failedResourceId) {
        this.itemResourceId = itemResourceId;
        this.loadingResourceId = loadingResourceId;
        this.failedResourceId = failedResourceId;
    }

    /**
     * Create a Section object with loading/failed states, a custom header but no footer
     * @param headerResourceId layout resource for its header
     * @param itemResourceId layout resource for its items
     * @param loadingResourceId layout resource for its loading state
     * @param failedResourceId layout resource for its failed state
     */
    public Section(int headerResourceId, int itemResourceId, int loadingResourceId, int failedResourceId) {
        this(itemResourceId, loadingResourceId, failedResourceId);
        this.headerResourceId = headerResourceId;
        hasHeader = true;
    }

    /**
     * Create a Section object with loading/failed states, a custom header and footer
     * @param headerResourceId layout resource for its header
     * @param footerResourceId layout resource for its footer
     * @param itemResourceId layout resource for its items
     * @param loadingResourceId layout resource for its loading state
     * @param failedResourceId layout resource for its failed state
     */
    public Section(int headerResourceId, int footerResourceId, int itemResourceId, int loadingResourceId, int failedResourceId) {
        this(headerResourceId, itemResourceId, loadingResourceId, failedResourceId);
        this.footerResourceId = footerResourceId;
        hasFooter = true;
    }

    /**
     * Set the State of this Section
     * @param state state of this section
     */
    public final void setState(State state) {
        this.state = state;
    }

    /**
     * Return the current State of this Section
     * @return current state of this section
     */
    public final State getState() {
        return state;
    }

    /**
     * Check if this Section is visible
     * @return true if this Section is vibisle
     */
    public final boolean isVisible() {
        return visible;
    }

    /**
     * Set if this Section is visible
     * @param visible true if this Section is visible
     */
    public final void setVisible(boolean visible) {
        this.visible = visible;
    }

    /**
     * Check if this Section has a header
     * @return true if this Section has a header
     */
    public final boolean hasHeader() {
        return hasHeader;
    }

    /**
     * Set if this Section has header
     * @param hasHeader true if this Section has a header
     */
    public final void setHasHeader(boolean hasHeader) {
        this.hasHeader = hasHeader;
    }

    /**
     * Check if this Section has a footer
     * @return true if this Section has a footer
     */
    public final boolean hasFooter() {
        return hasFooter;
    }

    /**
     * Set if this Section has footer
     * @param hasFooter true if this Section has a footer
     */
    public final void setHasFooter(boolean hasFooter) {
        this.hasFooter = hasFooter;
    }

    /**
     * Return the layout resource id of the header
     * @return layout resource id of the header
     */
    public final Integer getHeaderResourceId() {
        return headerResourceId;
    }

    /**
     * Return the layout resource id of the footer
     * @return layout resource id of the footer
     */
    public final Integer getFooterResourceId() {
        return footerResourceId;
    }

    /**
     * Return the layout resource id of the item
     * @return layout resource id of the item
     */
    public final int getItemResourceId() {
        return itemResourceId;
    }

    /**
     * Return the layout resource id of the loading view
     * @return layout resource id of the loading view
     */
    public final Integer getLoadingResourceId() {
        return loadingResourceId;
    }

    /**
     * Return the layout resource id of the failed view
     * @return layout resource id of the failed view
     */
    public final Integer getFailedResourceId() {
        return failedResourceId;
    }

    /**
     * Bind the data to the ViewHolder for the Content of this Section, that can be the Items,
     * Loading view or Failed view, depending on the current state of the section
     * @param holder ViewHolder for the Content of this Section
     * @param position position of the item in the Section, not in the RecyclerView
     */
    public final void onBindContentViewHolder(ViewHolder holder, int position) {
        switch (state) {
            case LOADING:
                onBindLoadingViewHolder(holder);
                break;
            case LOADED:
                onBindItemViewHolder(holder, position);
                break;
            case FAILED:
                onBindFailedViewHolder(holder);
                break;
            default:
                throw new IllegalStateException("Invalid state");
        }
    }

    /**
     * Return the total of items of this Section, including content items (according to the section
     * state) plus header and footer
     * @return total of items of this section
     */
    public final int getSectionItemsTotal() {
        int contentItemsTotal;

        switch (state) {
            case LOADING:
                contentItemsTotal = 1;
                break;
            case LOADED:
                contentItemsTotal = getContentItemsTotal();
                break;
            case FAILED:
                contentItemsTotal = 1;
                break;
            default:
                throw new IllegalStateException("Invalid state");
        }

        return contentItemsTotal + (hasHeader? 1 : 0) + (hasFooter? 1 : 0);
    }

    /**
     * Return the total of items of this Section
     * @return total of items of this Section
     */
    public abstract int getContentItemsTotal();

    /**
     * Return the ViewHolder for the Header of this Section
     * @param view View inflated by resource returned by getHeaderResourceId
     * @return ViewHolder for the Header of this Section
     */
    public ViewHolder getHeaderViewHolder(Context context,View view) {
        return new SectionRVAdapter.EmptyViewHolder(context,view);
    }

    /**
     * Bind the data to the ViewHolder for the Header of this Section
     * @param holder ViewHolder for the Header of this Section
     */
    public void onBindHeaderViewHolder(ViewHolder holder) {
        // Nothing to bind here.
    }

    /**
     * Return the ViewHolder for the Footer of this Section
     * @param view View inflated by resource returned by getFooterResourceId
     * @return ViewHolder for the Footer of this Section
     */
    public ViewHolder getFooterViewHolder(Context context,View view) {
        return new SectionRVAdapter.EmptyViewHolder(context,view);
    }

    /**
     * Bind the data to the ViewHolder for the Footer of this Section
     * @param holder ViewHolder for the Footer of this Section
     */
    public void onBindFooterViewHolder(ViewHolder holder) {
        // Nothing to bind here.
    }

    /**
     * Return the ViewHolder for a single Item of this Section
     * @param view View inflated by resource returned by getItemResourceId
     * @return ViewHolder for the Item of this Section
     */
    public abstract ViewHolder getItemViewHolder(View view,int viewType);
    /**
     * Bind the data to the ViewHolder for an Item of this Section
     * @param holder ViewHolder for the Item of this Section
     * @param position position of the item in the Section, not in the RecyclerView
     */
    public abstract void onBindItemViewHolder(ViewHolder holder, int position);

    /**
     * Return the ViewHolder for the Loading state of this Section
     * @param view View inflated by resource returned by getItemResourceId
     * @return ViewHolder for the Loading state of this Section
     */
    public ViewHolder getLoadingViewHolder(Context context,View view) {
        return new SectionRVAdapter.EmptyViewHolder(context,view);
    }
    /**
     * Bind the data to the ViewHolder for Loading state of this Section
     * @param holder ViewHolder for the Loading state of this Section
     */
    public void onBindLoadingViewHolder(ViewHolder holder) {
        // Nothing to bind here.
    }

    /**
     * Return the ViewHolder for the Failed state of this Section
     * @param view View inflated by resource returned by getItemResourceId
     * @return ViewHolder for the Failed of this Section
     */
    public ViewHolder getFailedViewHolder(Context context,View view) {
        return new SectionRVAdapter.EmptyViewHolder(context,view);
    }
    /**
     * Bind the data to the ViewHolder for the Failed state of this Section
     * @param holder ViewHolder for the Failed state of this Section
     */
    public void onBindFailedViewHolder(ViewHolder holder) {
        // Nothing to bind here.
    }
}