EmbeddedCardLayoutAdapter.java

/*
 * Copyright (C) 2014 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.google.android.glass.sample.apidemo.card;

import com.google.android.glass.sample.apidemo.R;
import com.google.android.glass.widget.CardBuilder;
import com.google.android.glass.widget.CardScrollAdapter;

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

import java.util.List;

/**
 * Populates views in a {@code CardScrollView} with cards built from custom embedded layouts to
 * represent items in a simple table.
 */
public class EmbeddedCardLayoutAdapter extends CardScrollAdapter {

    /** The maximum number of items that fit on a card. */
    private static final int ITEMS_PER_CARD = 4;

    /** Index of the {@link ImageView} containing the icon in a table row. */
    private static final int IMAGE_VIEW_INDEX = 0;

    /** Index of the {@link TextView} containing the primary text in a table row. */
    private static final int PRIMARY_TEXT_VIEW_INDEX = 1;

    /** Index of the {@link TextView} containing the secondary text in a table row. */
    private static final int SECONDARY_TEXT_VIEW_INDEX = 2;

    private final Context mContext;
    private final List<SimpleTableItem> mItems;

    /** Initializes a new adapter with the specified context and list of items. */
    public EmbeddedCardLayoutAdapter(Context context, List<SimpleTableItem> items) {
        mContext = context;
        mItems = items;
    }

    @Override
    public int getViewTypeCount() {
        return 1;
    }

    @Override
    public int getItemViewType(int position){
        return 0;
    }

    @Override
    public int getCount() {
        // Compute the number of cards needed to display the items with 4 per card (rounding up to
        // capture the remainder).
        return (int) Math.ceil((double) mItems.size() / ITEMS_PER_CARD);
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public int getPosition(Object item) {
        return AdapterView.INVALID_POSITION;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        CardBuilder card = new CardBuilder(mContext, CardBuilder.Layout.EMBED_INSIDE)
            .setEmbeddedLayout(R.layout.simple_table)
            .setFootnote(R.string.text_card_embedded_footnote)
            .setTimestamp(R.string.text_card_embedded_timestamp);
        View view = card.getView(convertView, parent);

        // Get a reference to an embedded view from the custom layout and then manipulate it.
        ViewGroup tableView = (ViewGroup) view.findViewById(R.id.simple_table);
        populateTableRows(position, tableView);

        return view;
    }

    /** Populates all of the rows in the card at the specified position. */
    private void populateTableRows(int position, ViewGroup tableView) {
        int startItemIndex = position * ITEMS_PER_CARD;
        int endItemIndex = Math.min(startItemIndex + ITEMS_PER_CARD, mItems.size());

        for (int i = 0; i < ITEMS_PER_CARD; i++) {
            int itemIndex = startItemIndex + i;
            ViewGroup rowView = (ViewGroup) tableView.getChildAt(i);

            // The layout contains four fixed rows, so we need to hide the later ones if there are
            // not four items on this card. We need to make sure to update the visibility in both
            // cases though if the card has been recycled.
            if (itemIndex < endItemIndex) {
                SimpleTableItem item = mItems.get(itemIndex);
                populateTableRow(item, rowView);
                rowView.setVisibility(View.VISIBLE);
            } else {
                rowView.setVisibility(View.INVISIBLE);
            }
        }
    }

    /** Populates a row in the table with the specified item data. */
    private void populateTableRow(SimpleTableItem item, ViewGroup rowView) {
        ImageView imageView = (ImageView) rowView.getChildAt(IMAGE_VIEW_INDEX);
        TextView primaryTextView = (TextView) rowView.getChildAt(PRIMARY_TEXT_VIEW_INDEX);
        TextView secondaryTextView = (TextView) rowView.getChildAt(SECONDARY_TEXT_VIEW_INDEX);

        imageView.setImageResource(item.iconResId);
        primaryTextView.setText(item.primaryText);
        secondaryTextView.setText(item.secondaryText);
    }
}