【原】Android中Adapter之SimpleCursorAdapter使用

         此Adapter(SimpleCursorAdapter)是Android专门为了连接数据库与视图而产生的.此例中借助ListView体现SimpleCursorAdapter的用法。因为，ListView在android中是比较常用的视图组件，不论是静态还是动态都可以在其上显示。当然，在实际的android项目中需要显示的数据一般都是动态从数据库表中获取的。而SimpleCursorAdapter就是将从数据库表中获取的数据显示到ListView的桥梁。

         在做的时候，可以将SimpleCursorAdapter与前面的SimpleCursorAdapter进行对比一下，你会发现二者的使用非常相似：

          1.在new xxxAdapter时候, 如下 ,红色字体，

               SimpleCursorAdapter adapter = new SimpleCursorAdapter(

                                                                                                  this,

                                                                                                  android.R.layout.simple_expandable_list_item_1,

                                                                                                  cursor,

                                                                                                  new String[]{People.NAME},

                                                                                                  new int[]{android.R.id.text1}

              );
              SimpleAdapter adapter = new SimpleAdapter(

                                                                                       this,

                                                                                       allInfos ,

                                                                                       R.layout.simple_adapter_view,

                                                                                       new String[]{"img","name","phone","region"},

                                                                                       new int[]{R.id.info_img,R.id.info_name,R.id.info_phone,R.id.info_region}

          )

 红色字体部分，即二者的数据源类型不同，SimpleCursorAdapter 的数据源是一个从数据库表中查询出来的数据集合cursor；而SimpleAdapter的数据源allInfos 是list集合(当然也可以是数组等)，可以看到一个是动态一个是静态的数据。

 

这里使用的SimpleCursorAdapter只是一个简单的例子，用的是系统表，当然你可以自己建立一个表应用在此例中，activity代码：

public class SimpleCursorAdapterTest extends Activity{
 private ListView listView;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
                 super.onCreate(savedInstanceState);
                 listView = new ListView(this);
                 Cursor myCursor = getContentResolver().query(People.CONTENT_URI, null, null, null, null);//是系统里的表
                 startManagingCursor(myCursor);
                 ListAdapter listAdapter = new SimpleCursorAdapter(

                                                                                                   this, //上下文

                                                                                                   android.R.layout.simple_expandable_list_item_1, //要显示的listview的样式

                                                                                                   myCursor, //数据源

                                                                                                   new String[]{People.NAME}, //所对应的字段

                                                                                                   new int[]{android.R.id.text1}   //上面的字段显示在界面上的那个控件

                 );
                 listView.setAdapter(listAdapter);
                 setContentView(listView);
 }
}

       值得注意的一点，不要忘了在AndroidManifest.xml文件中声明访问系统表的权限：<uses-permission android:name="android.permission.READ_CONTACTS"/>

如果该系统表中还没有数据，此时，所显示出来的ListView是空的，没有数据的。