A default adapter with viewholder and getview () method

DemoAdapter.java

package com.example.anim_play.adapter;

import java.util.List;

import org.json.JSONObject;

import com.example.anim_play.R;

import android.app.Activity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

public class DemoAdapter extends BaseAdapter{
  private List<JSONObject> listItems;

	private static class ViewHolder{
		/** The image view. */
		protected ImageView imageView;
		/** The location text. */
		protected TextView txtUserName;
	}
	
	/** The m context. */
	private Activity mContext;
	
	public DemoAdapter(Activity context){
		super();
		this.mContext=context;
		
	}
	
	
	public List<JSONObject> getListItems() {
		return listItems;
	}

	public void setListItems(List<JSONObject> listItems) {
		this.listItems = listItems;
	}

	@Override
	public int getCount() {
		if( listItems == null ) return 0;
		return listItems.size();
	}

	@Override
	public Object getItem(int arg0) {
		if( listItems == null ) return "";
		return listItems.get(arg0);
	}

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

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		if (getCount() < position)
			return null;

		ViewHolder holder = null;
		final JSONObject obj = listItems.get(position);
		if (convertView == null) {
			holder = new ViewHolder();
			convertView = mContext.getLayoutInflater().inflate(R.layout.user_row, null);
			holder.imageView = (ImageView)convertView.findViewById(R.id.img_user);
			holder.txtUserName = (TextView)convertView.findViewById(R.id.txt_user_name);
			convertView.setTag(holder);
			//set your values here
		} else {
			holder = (ViewHolder) convertView.getTag();
		}
		return convertView;
	}

}