ListView的优化 自己的demo

package com.su.testinray;

import java.util.List;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

public class CardListAdapter extends BaseAdapter {
	private Context context;
	private List<CardEntity> list;

	public CardListAdapter(Context context, List<CardEntity> list) {
		this.context = context;
		this.list = list;
	}

	@Override
	public int getCount() {
		return list.size();
	}

	@Override
	public Object getItem(int position) {
		return list.get(position);
	}

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

	public View getView(int position, View convertView, ViewGroup parent) {
		ViewHolder holder;
		final CardEntity info = list.get(position);
		if (convertView == null) {
			LayoutInflater mInflater = ((Activity) context).getLayoutInflater();
			convertView = mInflater.inflate(R.layout.list_item, null);
			holder = new ViewHolder();
			holder.textViewname = (TextView) convertView
					.findViewById(R.id.name);
			holder.textViewcardname = (TextView) convertView
					.findViewById(R.id.cardname);
			holder.textViewphonenum = (TextView) convertView
					.findViewById(R.id.phonenum);

			convertView.setTag(holder);
		} else {
			holder = (ViewHolder) convertView.getTag();
		}
		holder.textViewname.setText(info.getName());
		holder.textViewcardname.setText(info.getCardnum());
		holder.textViewphonenum.setText(info.getPhonenum());

		return convertView;
	}

	static class ViewHolder {
		TextView textViewname;
		TextView textViewcardname;
		TextView textViewphonenum;

	}

}