Android适配器Adapter学习

 在开发中我们需要绑定一些数据展现到桌面上，这是就需要AdapterView。AdapterView是ViewGroup的子类，它决定了怎么展现视图通过Adapter来绑定特殊的数据类型。 AdapterView是非常有帮助的当你展现数据在你的布局中。Gallery,ListView和 Spinner是AdapterView的子类。

      下面看一下AdapterView的结构图：

      

      然后再看一下Adapter的结构图：

     

    上面已经充分展现了他们的子类和父类的基础关系。

     下面我们看一个ListViewDemo的例子：

    先来看一个简单的adapter的例子：

   

 public class SimpleList extends ListActivity {
     private String[] mListString={"姓名：王魁锋","性别：男","年龄：23",
             "居住地：上海市普陀区","邮箱：[email protected]"};
     private ListView mListView=null;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         // TODO Auto-generated method stub
         super.onCreate(savedInstanceState);
         mListView=this.getListView();
         setListAdapter(new ArrayAdapter(this,
             android.R.layout.simple_list_item_1,mListString));
         mListView.setOnItemClickListener(new OnItemClickListener() {

             @Override
             public void onItemClick(AdapterView parent, View view,
                     int position, long id) {
                 // TODO Auto-generated method stub
             Toast.makeText(SimpleList.this, "你选择了："+mListString[position], 1).show();
             }
         });
     }

  这里用到了系统定义好的适配模式，当然这只能用来简单的数据适配，下面看一下效果：

    

    接下来看一个稍微复杂点的，SimpleAdapter怎么适配：

   

 public class IconList extends ListActivity {

      private String[] mListTitle = { "姓名", "性别", "年龄", "居住地","邮箱"};
         private String[] mListStr = { "王魁锋", "男", "23", "上海市普陀区",
             "[email protected]"};
         ListView mListView = null;
         ArrayList> mData= new ArrayList>();;

         @Override
         protected void onCreate(Bundle savedInstanceState) {
             // TODO Auto-generated method stub
              mListView = getListView();

             int lengh = mListTitle.length;
             for(int i =0; i < lengh; i++) {
                 Map item = new HashMap();
                 item.put("image", R.drawable.portrait);
                 item.put("title", mListTitle[i]);
                 item.put("text", mListStr[i]);
                 mData.add(item);
             }
             SimpleAdapter adapter = new SimpleAdapter(this,mData,R.layout.iconlist,
                 new String[]{"image","title","text"},new int[]{R.id.image,R.id.title,R.id.text});
                 setListAdapter(adapter);
             mListView.setOnItemClickListener(new OnItemClickListener() {
                 @Override
                 public void onItemClick(AdapterView parent, View view,
                         int position, long id) {
                     // TODO Auto-generated method stub
                      Toast.makeText(IconList.this,"您选择了标题：" + mListTitle[position] + "    内容："+mListStr[position], Toast.LENGTH_LONG).show();

                 }
             });
             super.onCreate(savedInstanceState);
         }
 }

    上面的数据可以是同数据库读取的也可以是从网络获取的，这里不做过多介绍,看下效果：

    

      哈哈 看起来美观了些，如果要做更复杂的布局，哪就要用BaseAdapter了。先看一下布局文件：

 xml version="1.0" encoding="utf-8"?>

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent" android:layout_height="wrap_content">
     <ImageView android:id="@+id/color_image"
         android:layout_width="wrap_content" android:layout_height="fill_parent"
         android:layout_alignParentTop="true" android:layout_alignParentBottom="true"
         android:adjustViewBounds="true"
         android:padding="2dip" />
     <TextView android:id="@+id/color_title"
         android:layout_width="fill_parent" android:layout_height="wrap_content"
         android:layout_toRightOf="@+id/color_image"
         android:layout_alignParentTop="true"
         android:layout_alignParentRight="true" android:singleLine="true"
         android:ellipsize="marquee"
         android:textSize="15dip"  />
     <TextView android:id="@+id/color_text"
         android:layout_width="fill_parent" android:layout_height="wrap_content"
         android:layout_toRightOf="@+id/color_image"
         android:layout_below="@+id/color_title"
         android:layout_alignParentBottom="true"
         android:layout_alignParentRight="true"
         android:singleLine="true"
         android:ellipsize="marquee"
         android:textSize="20dip" />
 RelativeLayout>

   
下面是核心代码：

 

 public class ColorList extends ListActivity {
      private String[] mListTitle = { "姓名", "性别", "年龄", "居住地","邮箱"};
      private String[] mListText={"王魁锋","男","23","上海市普陀区","[email protected]"};
      private ListView mListView=null;
      private MyListAdapter myAdapter=null;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         // TODO Auto-generated method stub
          mListView=this.getListView();
          myAdapter=new MyListAdapter(this);
          this.setListAdapter(myAdapter);

          mListView.setOnItemClickListener(new OnItemClickListener() {

             @Override
             public void onItemClick(AdapterView parent, View view,
                     int position, long id) {
                 // TODO Auto-generated method stub
                 View v=parent.getChildAt(position);
                 v.setBackgroundColor(Color.RED);
                 Toast.makeText(ColorList.this, "你选择了 "+mListText[position], 1).show();
             }
         });
         super.onCreate(savedInstanceState);
     }
     private class MyListAdapter extends BaseAdapter{
         private Context mContext;
         private int[] colors=new int[]{0xff626569,0xff4f5257 };
          public MyListAdapter(Context context){
              mContext=context;
          }
         @Override
         public int getCount() {
             // TODO Auto-generated method stub
             return mListText.length;
         }

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

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

         @Override
         public View getView(int position, View convertView, ViewGroup parent) {
             ImageView image=null;
             TextView title=null;
             TextView  content=null;
             if(convertView==null){
                 convertView=LayoutInflater.from(mContext).inflate(R.layout.colorlist, null);
                 image=(ImageView) convertView.findViewById(R.id.color_image);
                 title=(TextView) convertView.findViewById(R.id.color_title);
                 content=(TextView) convertView.findViewById(R.id.color_text);
             }
             int colorPos=position%colors.length;
             convertView.setBackgroundColor(colors[colorPos]);
             title.setText(mListTitle[position]);
             content.setText(mListText[position]);
             image.setImageResource(R.drawable.portrait);

             return convertView;
         }

     }
 }

     BaseAdapter可以让我们做比较复杂的布局，只要在xml文件中设置好布局格式，在getView中分别取出放入相应的值就可以了。下面看一些效果：

   


    还有一些SpinnerAdapter和SimpleCursorAdapter等系统自带的适配器，都是比较简单的，可以看下API自行练习一下，这里特别说明一下，从数据库里取出的数据最好直接放入 SimpleCursorAdapter很方便的。