Android支持展开/收缩功能的列表控件

最近在做一个Rss阅读器，看了下别人做的阅读器中的列表控件可以展开、收缩，我就在网上搜索了一下。下面就我找到的一个小例子，给大家分享一下。

ActivityMain .java

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package  study.com.android;   import  android.app.ExpandableListActivity; import  android.os.Bundle; import  android.view.ContextMenu; import  android.view.MenuItem; import  android.view.View; import  android.view.ContextMenu.ContextMenuInfo; import  android.widget.ExpandableListAdapter; import  android.widget.ExpandableListView; import  android.widget.TextView; import  android.widget.Toast; import  android.widget.ExpandableListView.ExpandableListContextMenuInfo;   public  class  ActivityMain  extends  ExpandableListActivity {        private  ExpandableListAdapter mAdapter;        @Override      public  void  onCreate(Bundle savedInstanceState) {          super .onCreate(savedInstanceState);          this .setTitle( "ExpandableList" );          mAdapter =  new  MyExpandableListAdapter( this );          setListAdapter(mAdapter);          registerForContextMenu( this .getExpandableListView());      }        // 为列表的每一项创建上下文菜单（即长按后 呼出的菜单）      @Override      public  void  onCreateContextMenu(ContextMenu menu, View v,              ContextMenuInfo menuInfo) {          menu.setHeaderTitle( "ContexMenu" );          menu.add( 0 ,  0 ,  0 ,  "ContextMenu" );      }        // 单击上下文菜单后的逻辑      @Override      public  boolean  onContextItemSelected(MenuItem item) {            ExpandableListContextMenuInfo info = (ExpandableListContextMenuInfo) item                  .getMenuInfo();          String title = ((TextView) info.targetView).getText().toString();            int  type = ExpandableListView                  .getPackedPositionType(info.packedPosition);          if  (type == ExpandableListView.PACKED_POSITION_TYPE_CHILD) {                int  groupPos = ExpandableListView                      .getPackedPositionGroup(info.packedPosition);              int  childPos = ExpandableListView                      .getPackedPositionChild(info.packedPosition);              Toast.makeText(                      this ,                      title +  "-Group Index"  + groupPos +  "Child Index:"                              + childPos, Toast.LENGTH_SHORT).show();              return  true ;          }          return  false ;      } }

MyExpandableListAdapter.java

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package  study.com.android;   import  android.content.Context; import  android.view.Gravity; import  android.view.View; import  android.view.ViewGroup; import  android.widget.AbsListView; import  android.widget.BaseExpandableListAdapter; import  android.widget.TextView;   public  class  MyExpandableListAdapter  extends  BaseExpandableListAdapter {        private  Context mContext;        // 父列表数据      private  String[] groups = {  "group1" ,  "group2" ,  "group3" ,  "group4" ,  "" };        // 子列表数据      private  String[][] children = { {  "child1"  }, {  "child1" ,  "child2"  },              {  "child1" ,  "child2" ,  "child3"  },              {  "child1" ,  "child2" ,  "child3" ,  "child4"  }, };        MyExpandableListAdapter(Context context) {          mContext = context;      }        @Override      public  Object getChild( int  groupPosition,  int  childPosition) {          // TODO Auto-generated method stub          return  children[groupPosition][childPosition];      }        @Override      public  long  getChildId( int  groupPosition,  int  childPosition) {          // TODO Auto-generated method stub          return  childPosition;      }        // 取子列表中的某一项的view      @Override      public  View getChildView( int  groupPosition,  int  childPosition,              boolean  isLastChild, View convertView, ViewGroup parent) {          TextView textView = getGenericView();          ;          textView.setText(getChild(groupPosition, childPosition).toString());          return  textView;      }        @Override      public  int  getChildrenCount( int  groupPosition) {          // TODO Auto-generated method stub          return  children[groupPosition].length;      }        @Override      public  Object getGroup( int  groupPosition) {          return  groups[groupPosition];      }        @Override      public  int  getGroupCount() {          // TODO Auto-generated method stub          return  groups.length;      }        @Override      public  long  getGroupId( int  groupPosition) {          // TODO Auto-generated method stub          return  groupPosition;      }        @Override      public  View getGroupView( int  groupPosition,  boolean  isExpanded,              View convertView, ViewGroup parent) {          TextView textView = getGenericView();          textView.setText(getGroup(groupPosition).toString());            return  textView;      }        @Override      public  boolean  hasStableIds() {          // TODO Auto-generated method stub          return  true ;      }        @Override      public  boolean  isChildSelectable( int  groupPosition,  int  childPosition) {          // TODO Auto-generated method stub          return  true ;      }        // 获取某一项的view的逻辑      private  TextView getGenericView() {          AbsListView.LayoutParams lp =  new  AbsListView.LayoutParams(                  ViewGroup.LayoutParams.FILL_PARENT,  48 );          TextView textView =  new  TextView(mContext);          textView.setLayoutParams(lp);          textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);          textView.setPadding( 32 ,  0 ,  0 ,  0 );          return  textView;      }   }

运行的结果如下：