listview改变字体大小

效果：点击字体，字体变大

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

ListText.java

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;
    	
    }
    
  }

<?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>