模拟新浪微博随便看看栏目

一.【分析】

要想完成这个功能，我们需要以下几个重要的地方：

1.ListView及ListView_Item

2.实体类的编写

3.自定义适配器的书写(最重要，此功能我们继承是BaseAdapter)

4.ListView的绑定数据源与控件

二.【编码】

 

 

(1)首先先看一下自定义适配器MyAdapter:

 

package cn.edu.bzu.adapter;

  

import java.util.List;

  

import cn.edu.bzu.entity.Information;

import cn.edu.bzu.weibo_looking.R;

import android.content.Context;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.ImageView;

import android.widget.TextView;

  

/**

 * 自定义Adapter实现listView的显示

 * @author monster

 * @date : 2015-04-28

 */

public class MyAdapter extends BaseAdapter {

    private List<Information> list;

    private Context mContext;

    private LayoutInflater mInflater;

    //定义构造方法

    public MyAdapter(List<Information> list, Context mContext) {

        super();

        this.list = list;

        this.mContext = mContext;

    }

  

    @Override

    public int getCount() {

        return list.size();

    }

  

    @Override

    public Object getItem(int position) {

        return list.get(position);

    }

  

    @Override

    public long getItemId(int position) {

        return position;

    }

  

    @Override

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

        ViewHolder holder=null;

        if(convertView==null){

            convertView=mInflater.from(mContext).inflate(R.layout.listview_item,null);  //布局转换成视图

            holder=new ViewHolder();

            //实例化控件

            holder.Image=(ImageView)convertView.findViewById(R.id.Iv);

            holder.Name=(TextView)convertView.findViewById(R.id.Name);

            holder.Time=(TextView)convertView.findViewById(R.id.Time);

            holder.Contents=(TextView)convertView.findViewById(R.id.Contents);

            convertView.setTag(holder); //设置setTag使得程序得以优化

        }else{

            holder=(ViewHolder) convertView.getTag();

        }

        //给控件赋值

        holder.Image.setBackgroundResource(list.get(position).getImgId());

        holder.Name.setText(list.get(position).getName());

        holder.Time.setText(list.get(position).getDate());

        holder.Contents.setText(list.get(position).getContent());

        return convertView;

    }

      

    class ViewHolder{

        ImageView Image;

        TextView  Name;

        TextView  Time;

        TextView  Contents;

    }

}

 

在继承BaseAdapter 需要实现getCount  ，getItem，getItemId，getView，以及构造方法 等方法，里面最重要的是getView方法，本文用到ViewHolder设计模式，具体的ViewHolder设计模式的优点**

 

（2）MainActivity的编

package cn.edu.bzu.weibo_looking;

  

import java.util.ArrayList;

import java.util.List;

  

import cn.edu.bzu.adapter.MyAdapter;

import cn.edu.bzu.entity.Information;

import android.os.Bundle;

import android.widget.ListView;

import android.app.Activity;

  

public class MainActivity extends Activity {

    private ListView listView;

    private MyAdapter adapter;

    private List<Information> list;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        setData();//数据源

         initView();

    }

    private void initView() {

        // 初始化控件

        listView=(ListView) findViewById(R.id.Lv);

        listView.setAdapter(adapter);  //绑定适配器

    }

    private void setData() {

        // 设置数据源

         list=new ArrayList<Information>();

        list.add(new Information(R.drawable.img1,"潇湘夜雨","1分钟前",""));

        list.add(new Information(R.drawable.img2, "小小", "12分钟前", "我涨工资了，好开森"));

        list.add(new Information(R.drawable.img3,"青春无悔","1小时前","他真的变了好多"));

        list.add(new Information(R.drawable.img4,"小丸子","2小时前","请问你是"));

        adapter=new MyAdapter(list, MainActivity.this);

    }           

}

 

 

**在书写MainActivity的时候：

 

1.建立数据源

2.实例化控件

3.绑定适配器

**