ListView的BaseAdapter的基本使用和ViewHolder模式的适配

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第一步呀BaseAdapter用ListView的布局

1.新建一个main.xml 文件

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android=http://schemas.android.com/apk/res/android

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >

<ListView android:id="@+id/lv"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:fastScrollEnabled="true" /></LinearLayout>

2.新建一个list_item.xml文件

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" a

ndroid:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="horizontal" >

<ImageView android:id="@+id/img"

android:layout_width="wrap_content"

android:layout_height="wrap_content" />

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:orientation="vertical" >

<TextView android:id="@+id/tv"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textSize="20sp" />

<TextView android:id="@+id/info"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textSize="14sp" />

</LinearLayout>

public class Demo17Activity extends Activity {

private ListView lv;

private List<Map<String, Object>> data;

@Override

public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);

setContentView(R.layout.main);

lv = (ListView)findViewById(R.id.lv); //获取将要绑定的数据设置到

data中 data = getData();

MyAdapter adapter = new MyAdapter(this); lv.setAdapter(adapter); }

private List<Map<String, Object>> getData() { List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();

Map<String, Object> map;

for(int i=0;i<10;i++) { m

ap = new HashMap<String, Object>();

map.put("img", R.drawable.ic_launcher);

map.put("title", "跆拳道"); map.put("info", "快乐源于生活..."); list.add(map); } return list; } //ViewHolder静态类 static class ViewHolder { public ImageView img; public TextView title; public TextView info; } public class MyAdapter extends BaseAdapter { private LayoutInflater mInflater = null; private MyAdapter(Context context) { //根据context上下文加载布局，这里的是Demo17Activity本身，即this this.mInflater = LayoutInflater.from(context); } @Override public int getCount() { //How many items are in the data set represented by this Adapter. //在此适配器中所代表的数据集中的条目数 return data.size(); } @Override public Object getItem(int position) { // Get the data item associated with the specified position in the data set. //获取数据集中与指定索引对应的数据项 return position; } @Override public long getItemId(int position) { //Get the row id associated with the specified position in the list. //获取在列表中与指定索引对应的行id return position; } //Get a View that displays the data at the specified position in the data set. //获取一个在数据集中指定索引的视图来显示数据 @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = null; //如果缓存convertView为空，则需要创建View if(convertView == null) { holder = new ViewHolder(); //根据自定义的Item布局加载布局 convertView = mInflater.inflate(R.layout.list_item, null); holder.img = (ImageView)convertView.findViewById(R.id.img); holder.title = (TextView)convertView.findViewById(R.id.tv); holder.info = (TextView)convertView.findViewById(R.id.info); //将设置好的布局保存到缓存中，并将其设置在Tag里，以便后面方便取出Tag convertView.setTag(holder); }else { holder = (ViewHolder)convertView.getTag(); } holder.img.setBackgroundResource((Integer)data.get(position).get("img")); holder.title.setText((String)data.get(position).get("title")); holder.info.setText((String)data.get(position).get("info")); return convertView; } }}

第二

package com.yee4.samplelistviewdemo;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;

public class BaseActivity extends Activity {
ListView mListView;
private MyAdapter myAdapter;
private MyAdapter2 myAdapter2;

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);



  mListView = (ListView) findViewById(R.id.mListView);



  initData1();

}

//---------------------------方法一----------------------------------------
//数据加载方式一
private void initData1(){
  myAdapter = new MyAdapter(this);
  mListView.setAdapter(myAdapter);

  List<Map<String,String>> list = new ArrayList<Map<String,String>>();


  for(int i = 0 ; i < 50;i ++ )
  {
   Map<String,String> map = new HashMap<String, String>();
   map.put("tv", "firstNameT"+i);
   map.put("if", "secondNameTextView"+i);
   list.add(map);
  }
  //设置数据源
  myAdapter.setData(list);
}

public class MyAdapter extends BaseAdapter{



    private LayoutInflater mInflater = null;
    private List<Map<String,String>> data;

         private MyAdapter(Context context){
             //根据context上下文加载布局，这里的是Demo17Activity本身，即this
             this.mInflater = LayoutInflater.from(context);
         }

         //设置外部数据
         public void setData(List<Map<String,String>> list){

         this.data =list;

         //通知listview 数据改变了刷页面
         this.notifyDataSetChanged();

}

         //获取数据也的大小（个数）
  @Override
  public int getCount() {
   // TODO Auto-generated method stub
   if(data!=null){
    return data.size();
   }

   return 0;
  }

  //获取每个item数据
  @Override
  public Map<String,String> getItem(int point) {
   // TODO Auto-generated method stub
   return data.get(point);
  }

  @Override
  public long getItemId(int arg0) {
   // TODO Auto-generated method stub
   return 0;
  }

  //加载视图文件
  @Override
  public View getView(int point, View convertView, ViewGroup arg2) {
   // TODO Auto-generated method stub


   //视图绑定，如果视图为空，重新加载一个视图
            if(convertView == null){
                convertView = mInflater.inflate(R.layout.list_item, null);

            }

            //--------------------------------------------------------

            //数据邦迪
            Map<String,String> item =getItem(point);
            if(item!=null){
            TextView tvTextView = (TextView)convertView.findViewById(R.id.tv);
            tvTextView.setText(item.get("tv"));


                TextView infoTextView = (TextView)convertView.findViewById(R.id.info);
                infoTextView.setText(item.get("if"));

            }

            return convertView;
  }
}

//----------------方法二-------------------------
private void intData2(){

   myAdapter2=new MyAdapter2(this);
   mListView.setAdapter(myAdapter2);

   List<ListDataItem> list = new ArrayList<ListDataItem>();
   for(int i = 0 ; i < 50;i ++ )
   {
    ListDataItem item1 =new ListDataItem();
    item1.setTv("第"+i+"个");
    item1.setInf("secondNameTextView"+i);
    list.add(item1);
   }


   //设置数据源
   myAdapter2.setData(list);

}

public class MyAdapter2 extends BaseAdapter{
   private LayoutInflater mInflater = null;
   private List<ListDataItem> data;

   private MyAdapter2(Context context){
    this.mInflater = LayoutInflater.from(context);

   }

   public void setData(List<ListDataItem> data){
    this.data = data;
    this.notifyDataSetChanged();
   }

  @Override
  public int getCount() {
   // TODO Auto-generated method stub
   if(data!=null){
    return data.size();
   }
   return 0;
  }

  @Override
  public ListDataItem getItem(int point) {
   // TODO Auto-generated method stub
   return data.get(point);
  }

  @Override
  public long getItemId(int arg0) {
   // TODO Auto-generated method stub
   return 0;
  }

  @Override
  public View getView(int point, View convertView, ViewGroup arg2) {
   // TODO Auto-generated method stub
   //视图绑定，如果视图为空，重新加载一个视图
            if(convertView == null){
                convertView = mInflater.inflate(R.layout.list_item, null);

            }

            ListDataItem item =getItem(point);

            if(item!=null){
            TextView tvTextView = (TextView)convertView.findViewById(R.id.tv);
            tvTextView.setText(item.getTv());


                TextView infoTextView = (TextView)convertView.findViewById(R.id.info);
                infoTextView.setText(item.getInf());

            }
   return convertView;
  }

}

private class ListDataItem{
   private String tv;
   private String inf;
  public String getTv() {
   return tv;
  }
  public void setTv(String tv) {
   this.tv = tv;
  }
  public String getInf() {
   return inf;
  }
  public void setInf(String inf) {
   this.inf = inf;
  }


}

}

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