EndlessListView.java

package com.survivingwithandroid.endlessadapter;

/*
 * Copyright (C) 2012 Surviving with Android (http://www.survivingwithandroid.com)
 *
 * 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.
 */

import java.util.List;

import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AbsListView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.AbsListView.OnScrollListener;

public class EndlessListView extends ListView implements OnScrollListener {
	
	private View footer;
	private boolean isLoading;
	private EndlessListener listener;
	private EndlessAdapter adapter;
	
	public EndlessListView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);	
		this.setOnScrollListener(this);
	}

	public EndlessListView(Context context, AttributeSet attrs) {
		super(context, attrs);
		this.setOnScrollListener(this);
	}

	public EndlessListView(Context context) {
		super(context);		
		this.setOnScrollListener(this);
	}
	
	public void setListener(EndlessListener listener) {
		this.listener = listener;
	}

	@Override
	public void onScroll(AbsListView view, int firstVisibleItem,
			int visibleItemCount, int totalItemCount) {
				
		if (getAdapter() == null)
			return ;
		
		if (getAdapter().getCount() == 0)
			return ;
		
		int l = visibleItemCount + firstVisibleItem;
		if (l >= totalItemCount && !isLoading) {
			// It is time to add new data. We call the listener
			this.addFooterView(footer);
			isLoading = true;
			listener.loadData();
		}
	}

	@Override
	public void onScrollStateChanged(AbsListView view, int scrollState) {}
	
	public void setLoadingView(int resId) {
		LayoutInflater inflater = (LayoutInflater) super.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
		footer = (View) inflater.inflate(resId, null);
		this.addFooterView(footer);
		
	}

	
	public void setAdapter(EndlessAdapter adapter) {		
		super.setAdapter(adapter);
		this.adapter = adapter;
		this.removeFooterView(footer);
	}

	
	public void addNewData(List<String> data) {
		
		this.removeFooterView(footer);
		
		adapter.addAll(data);
		adapter.notifyDataSetChanged();
		isLoading = false;
	}
	
	
	public EndlessListener setListener() {
		return listener;
	}


	public static interface EndlessListener {
		public void loadData() ;
	}
	
}