ListView的自动加载

已经学android已经有好几个月了，当我添加列表时，我会想到用listview 来装载，方便也可以实现多样性。但是之前只是实现的是一定数量的加载，要是数据多了怎么管理数据，就没去考虑，最近要做一个新闻显示的列表，这个就要实现一定数量的内容显示，所以借鉴了网上了一些做法，特此积累下来。

好吧，先让大家看看效果图吧：

（网速不给力，暂没能上传）

        布局文件有三个：

           main.xml

<?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" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />
   <ListView 
       android:id="@+id/lv"
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       ></ListView>

</LinearLayout>

item.xml

 

<?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" >

    <TextView 
        android:text="henhao"
        android:id="@+id/tvs"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textSize="18dip"
        />

</LinearLayout>

loading.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/loading_layout"
    android:layout_width="fill_parent"
     android:layout_height="fill_parent"
    android:orientation="vertical"
     android:gravity="center_horizontal"
    >
    <RelativeLayout
        android:id="@+id/load_id"
        android:orientation="horizontal" 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        >
        
        <TextView 
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:gravity="center_vertical"
            android:text="Loading..."
            android:textSize="12pt" />
        
        <ProgressBar android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="center_vertical"
            android:layout_alignParentRight="true"/>
    </RelativeLayout>
</LinearLayout>

java源文件就有两个：

 ListviewLoadActivity.java

package net.load.cn;

import java.util.ArrayList;
import java.util.List;

import android.R.array;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.AbsListView.OnScrollListener;

public class ListviewLoadActivity extends Activity implements OnScrollListener{
    ListView list;
    ArrayList<String> data;
    private int currentpage=1;
    private int pagesize=20;
    boolean isloading=false;
    private View loadingView;
    int last_item_position;
    CustomAdpter custAdpter;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        list=(ListView)findViewById(R.id.lv);
        data=UpdateData.getMyData(currentpage,pagesize);
        loadingView=LayoutInflater.from(this).inflate(R.layout.loading, null);
        list.addFooterView(loadingView);
        custAdpter=new CustomAdpter();
        list.setAdapter(custAdpter);
        list.setOnScrollListener(this);
        
        
    }
    Handler hand=new Handler(){
            public void handleMessage(android.os.Message msg){
                custAdpter.count=currentpage*pagesize;
                custAdpter.notifyDataSetChanged();
                hand.removeMessages(0);
                list.removeFooterView(loadingView);
                isloading=false;
            }
            
        };
    
    
    
    private void updateData()
    {
        try{
            Thread.sleep(3000);
        }catch (Exception e) {
            // TODO: handle exception
        }
        currentpage++;
        
        ArrayList<String> mydata=new ArrayList<String>();
         
        mydata=UpdateData.getMyData(currentpage, pagesize);
        for(String item:mydata){
            data.add(item);
        }
         
    }
    
    
    
     
    class CustomAdpter extends BaseAdapter{

        public int count=data.size();
        @Override
        public int getCount() {
            return count;
        }

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

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

        
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View v=LayoutInflater.from(ListviewLoadActivity.this).inflate(R.layout.item, null);
            TextView tv=(TextView)v.findViewById(R.id.tvs);
            tv.setText(data.get(position));
            return v;
        }
        
    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem,
            int visibleItemCount, int totalItemCount) {
        last_item_position=firstVisibleItem+visibleItemCount-1;
        if(last_item_position==totalItemCount-2){
        Toast.makeText(ListviewLoadActivity.this, "加载中...", 1).show();
              if(!isloading){
                  new Thread(){
                      public void run(){
                          isloading=true;
                          updateData();
                          hand.sendEmptyMessage(0);
                      }
                  }.start();
                }
          }
        if(list.getFooterViewsCount()==0){
            list.addFooterView(loadingView);
        }
        
    }
     @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        // TODO Auto-generated method stub
        //Toast.makeText(ListviewLoadActivity.this, "已经更新", 1).show();
    }
    
    
}

UpdateData.java

/**
* filename  : UpdateData.java
* company   : **** Limited (android) 2012-2015 
* compiler  : eclipse 3.7.1
* remark    : TODO 
* created   : 2012-3-14 weeds
* changed   : 后来者居下
*/

package net.load.cn;

import java.util.ArrayList;

/**
 * filename : TODO
 */
public class UpdateData {
 
    public static ArrayList<String> getMyData(int curr,int pagesize){
        ArrayList<String> listed=new ArrayList<String>();
        for(int i=(curr-1)*pagesize;i<curr*pagesize;i++)
        {
            listed.add("这是第"+i+"个列表");
        }
        return listed;
    }
}