BuildingBlockDescListAdapter.java

/**
    @contributor(s): Erlend Stav (SINTEF)

	Copyright 2012 SINTEF, http://www.sintef.no
	
	This software was developed in the UbiCompForAll project.
	
	See the NOTICE file distributed with this work for additional 
	information regarding copyright ownership and the 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 org.ubicompforall.ubicomposer.android;

import java.util.List;

import org.ubicompforall.descriptor.BuildingBlockDesc;

import android.content.Context;
import android.net.Uri;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

/**
 * Adapter class for a list of building block descriptors, allow
 * presentation of the building blocks in a palette-like list showing 
 * their icon and user friendly name.
 * @author erlend
 *
 */
public class BuildingBlockDescListAdapter extends ArrayAdapter<BuildingBlockDesc> {

	LayoutInflater inflater;
	
	/**
	 * Helper class that holds the icon and text fields that are used for to display
	 * a line in the list.
	 */
	static class ViewHolder {
		ImageView bbIcon;
		TextView bbText;
	}
	
	public BuildingBlockDescListAdapter(Context context, int resource,
			int textViewResourceId, List<BuildingBlockDesc> objects) {
		super(context, resource, textViewResourceId, objects);
		inflater = LayoutInflater.from(context);
	}
	
		
	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		ViewHolder holder;
		
		if (convertView == null) {
			// Created the view by inflating its layout and create a holder that keeps
			// track of the icon and text views for later access 
			convertView = inflater.inflate(R.layout.ubicomposer_buildingblockdesc_layout, null);
			holder = new ViewHolder();
			holder.bbIcon = (ImageView)convertView.findViewById(R.id.ubicomposer_buildingBlockIconView);
			holder.bbText = (TextView)convertView.findViewById(R.id.ubicomposer_buildingBlockNameText);
			// Register the holder as a tag on the view
			convertView.setTag(holder);
		}
		else {
			// Retrieve the holder from the tag of the view
			holder = (ViewHolder)convertView.getTag();
		}
		
		Object crItem = this.getItem(position);
		if (crItem instanceof BuildingBlockDesc) {
			
			// First, retrieve the icon based on URL using the holder to find the icon view
			// TODO: consider to optimize this by caching images
			String iconFileName = "";
			try {
				iconFileName = parent.getContext().getFileStreamPath(((BuildingBlockDesc) crItem).getIconUrl()).getAbsolutePath();
				holder.bbIcon.setImageURI(Uri.parse(iconFileName));
			} catch (Exception e) {
				holder.bbIcon.setImageURI(null);
			}
			
			// Next, set the text description using the holder to find the text view
			holder.bbText.setText(((BuildingBlockDesc) crItem).getUserFriendlyName());
		}
		
		return convertView;
	}
	
	
}