效果：点击字体，字体变大

主要利用的getView()方法和setOnItemClickListener()方法

ListText.java

复制代码 代码如下:

package lt.com;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import android.app.Activity;

import android.app.AlertDialog;

import android.app.ListActivity;

import android.content.Context;

import android.content.DialogInterface;

import android.os.Bundle;

import android.util.Log;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.AdapterView;

import android.widget.BaseAdapter;

import android.widget.Button;

import android.widget.ImageView;

import android.widget.ListView;

import android.widget.TextView;

import android.widget.AdapterView.OnItemClickListener;

public class ListText extends Activity {

List<Map<String,Object>> mData;

public static int select_item = -1;

//MyAdapter adapter;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

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

mData= GetDate();

final MyAdapter adapter =new MyAdapter(this);

lv.setAdapter(adapter);

Log.v("tag", "100");

//点击事件

lv.setOnItemClickListener(new OnItemClickListener(){

public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,

long arg3) {

select_item = arg2; //当前选择的item

adapter.notifyDataSetChanged(); //通知adapter刷新数据

Log.v("tag", "1");

}

public void onNothingSelected(AdapterView<?> arg0) {

}

});

}

//item相关信息 名称 图片

public List<Map<String,Object>> GetDate(){

List<Map<String,Object>> list=new ArrayList<Map<String,Object>>(); //存在一个大仓库，摆放着很多抽屉 ，list相当把抽屉放进仓库。

// 这是upcast 或者ArrayList<Map<String,Object>> list=new ArrayList<Map<String,Object>>();也行

Map<String,Object> map=new HashMap<String,Object>();//抽屉，里面有东西。

map.put("text", "中国");//把东西放到抽屉里面

list.add(map);//把抽屉放到仓库里

HashMap<String,Object> map1=new HashMap<String,Object>();

map1.put("text", "美国");

list.add(map1);

HashMap<String,Object> map2=new HashMap<String,Object>();

map2.put("text", "日本");

list.add(map2);

return list;

}

//自定义适配器

public class MyAdapter extends BaseAdapter{

private LayoutInflater mInflater;//Instantiates a layout XML file into its corresponding View objects.

private int select_item;

public MyAdapter(Context context){

this.mInflater = LayoutInflater.from(context);//Obtains the LayoutInflater from the given context.

}

//item的数量

public int getCount() {

// TODO Auto-generated method stub

return mData.size();

}

public Object getItem(int arg0) {

// TODO Auto-generated method stub

return null;

}

public long getItemId(int position) {

// TODO Auto-generated method stub

return 0;

}

//convertView是复用的view，如果没有旧的就新建个新的view；parent是listview

public View getView(int position, View convertView, ViewGroup parent) {

// TODO Auto-generated method stub

ViewHolder holder = null;

if(convertView==null){

holder=new ViewHolder();

convertView=mInflater.inflate(R.layout.main, null);//Inflate a new view hierarchy from the specified xml resource.

holder.texta = (TextView)convertView.findViewById(R.id.text);

convertView.setTag(holder);//Sets the tag associated with this view ， A tag can be used to mark a view in its hierarchy and does not have to be unique within the hierarchy.

//这个view是holder绘制的

}

else{

holder = (ViewHolder)convertView.getTag();//get tag

}

holder.texta.setText((String)mData.get(position).get("text"));

this.select_item = ListText.select_item;

try{

if(this.select_item == position){

holder.texta.setTextSize(50); //选中的Item字体：50px

Log.v("tag", "3");

}

else

holder.texta.setTextSize(20); //未选中的Item字体：10px

Log.v("tag", "2");

}catch(Exception ex){

ex.printStackTrace();

}

return convertView;

}

}

/** listView 中某项被选中后的逻辑

protected void onListItemClick(ListView l, View v, int position, long id) {

select_item = position; //当前选择的item

// adapter.notifyDataSetChanged(); //通知adapter刷新数据

Log.v("tag", "1");

}

*/

public final class ViewHolder{

TextView texta;

}

}

main.xml

复制代码 代码如下:

<?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="match_parent"

android:layout_height="match_parent"

>

</ListView>

<TextView

android:id="@+id/text"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

/>

</LinearLayout>