本案例学习来自 _鸿洋_ 大神,自己在写一遍,加深记忆  

 

 

我们都是以前写listView  都是这个样子

1 package com.example.listviewdemo; 2  3 import java.util.ArrayList; 4 import java.util.List; 5  6 import android.app.Activity; 7 import android.os.Bundle; 8 import android.widget.ListView; 9 10 public class MainActivity extends Activity {11 12     private ListView lv ;13     private List
     
       list = new ArrayList
      
       ();14     15     @Override16     protected void onCreate(Bundle savedInstanceState) {17         super.onCreate(savedInstanceState);18         setContentView(R.layout.activity_main);19         initData();20         lv = (ListView) findViewById(R.id.id_main_lv);21         MyAdapter
       
         adapter = new MyAdapter
        
         (list,this);22         lv.setAdapter(adapter);23     }24 25     private void initData() {26         for(int i=0;i<30;i++){27             list.add("qqqqq"+i);28         }29     }30 31     32 }
        
       
      
     

 

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1 package com.example.listviewdemo; 2  3 import java.util.List; 4  5 import android.content.Context; 6 import android.view.View; 7 import android.view.ViewGroup; 8 import android.widget.BaseAdapter; 9 import android.widget.TextView;10 11 public class MyAdapter
     
       extends BaseAdapter {12 13     private List
      
        list;14     private Context mContext;15     public MyAdapter(List
       
         list,Context mContext) {16         super();17         this.list = list;18         this.mContext = mContext;19     }20 21     22     @Override23     public int getCount() {24         // TODO Auto-generated method stub25         return list.size();26     }27 28     @Override29     public Object getItem(int position) {30         // TODO Auto-generated method stub31         return list.get(position);32     }33 34     @Override35     public long getItemId(int position) {36         // TODO Auto-generated method stub37         return position;38     }39 40     @Override41     public View getView(int position, View convertView, ViewGroup parent) {42         43         ViewHolder holder = null;44         if(convertView == null){45             holder = new ViewHolder();46             convertView = View.inflate(mContext, R.layout.item_listview, null);47             holder.tv = (TextView) convertView.findViewById(R.id.item_tv);48             convertView.setTag(holder);49         }else{50             holder  =    (ViewHolder) convertView.getTag();51         }52         holder.tv.setText((String)list.get(position));53         System.out.println((String)list.get(position));54         return convertView;55     }56 57      class ViewHolder{58          TextView tv ;59     }60 }
       
      
     

 

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