listview（1、BaseAdapter）

listview是APP开发中最常用的UI之一，在android中采用适配器的设计模式，关联UI界面及数据。例子如下：

1、定义listview中每个list的界面，创建item_list.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
 
 
    <ImageView android:id="@+id/image" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" 
        android:layout_margin="5px"/>
 
    <LinearLayout android:orientation="vertical"
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content">
 
        <TextView android:id="@+id/title" 
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" 
            android:textColor="#FFFFFFFF"
            android:textSize="22px" />
        <TextView android:id="@+id/content" 
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" 
            android:textColor="#FFFFFFFF"
            android:textSize="13px" />
 
    </LinearLayout>
</LinearLayout>

2. 定义适配器，继承BaseAdapter

public class Adapter1 extends BaseAdapter {

    private LayoutInflater mInflater = null;
    
    public Adapter1(Context context) {
        super(); 
        mInflater = (LayoutInflater) context  
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);  
        
    }

    @Override
    public int getCount() {
        return 100;
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;    
        if (convertView == null) {
            Log.i("tag", "convertView == null");
            holder = new ViewHolder();    
            convertView = mInflater.inflate(R.layout.item_list, null);  
            holder.image   = (ImageView) convertView.findViewById(R.id.image);    
            holder.title   = (TextView) convertView.findViewById(R.id.title);    
            holder.content = (TextView) convertView.findViewById(R.id.content);     
            
            //捆绑已经创建的对象
            convertView.setTag(holder);    
        } else {
            Log.i("tag", "convertView != null");
            holder = (ViewHolder) convertView.getTag();    
        }  
  
        holder.image.setImageResource(R.drawable.ic_launcher);  
        holder.title.setText("title");  
        holder.content.setText("content" + position); 
        return convertView;
    }
}

3. 在activity中定义此适配器，本例中采用listActivity

Adapter1 adapter = new Adapter1(this.getApplicationContext());
setListAdapter(adapter);