Android中ExpandableListView的使用

ExpandableListView是android中可以实现下拉list的一个控件，具体的实现方法如下：

首先：在layout的xml文件中定义一个ExpandableListView

< LinearLayout         android:id ="@+id/linearLayout"        android:layout_width ="fill_parent"         android:layout_height ="fill_parent"        androidrientation ="vertical"        >               < ExpandableListView        android:id ="@+id/expandableListView"        android:layout_width ="fill_parent"        android:layout_height ="wrap_content"            />    </ LinearLayout >

定义两个List，用来存放控件中Group/Child中的String

private  List<String> groupArray;   private  List<List<String>> childArray;

对这两个List进行初始化，并插入一些数据

groupArray = new  ArrayList<String>();   childArray = new  ArrayList<List<String>>();      groupArray.add("第一行" );   groupArray.add("第二行" );      List<String> tempArray = new  ArrayList<String>();   tempArray.add("第一条" );   tempArray.add("第二条" );   tempArray.add("第三条" );      for (int  index = 0 ; index <groupArray.size(); ++index)   {       childArray.add(tempArray);   }

定义ExpandableListView的Adapter

//ExpandableListView的Adapter    public  class  ExpandableAdapter extends  BaseExpandableListAdapter   {       Activity activity;              public  ExpandableAdapter(Activity a)       {           activity = a;       }       public  Object getChild(int  groupPosition, int  childPosition)       {           return  childArray.get(groupPosition).get(childPosition);       }       public  long  getChildId(int  groupPosition, int  childPosition)       {           return  childPosition;       }       public  int  getChildrenCount(int  groupPosition)       {           return  childArray.get(groupPosition).size();       }       public  View getChildView(int  groupPosition, int  childPosition,               boolean  isLastChild, View convertView, ViewGroup parent)       {           String string = childArray.get(groupPosition).get(childPosition);           return  getGenericView(string);       }       // group method stub        public  Object getGroup(int  groupPosition)       {           return  groupArray.get(groupPosition);       }       public  int  getGroupCount()       {           return  groupArray.size();       }       public  long  getGroupId(int  groupPosition)       {           return  groupPosition;       }       public  View getGroupView(int  groupPosition, boolean  isExpanded,               View convertView, ViewGroup parent)       {           String string = groupArray.get(groupPosition);           return  getGenericView(string);       }       // View stub to create Group/Children 's View        public  TextView getGenericView(String string)       {           // Layout parameters for the ExpandableListView            AbsListView.LayoutParams layoutParams = new  AbsListView.LayoutParams(                   ViewGroup.LayoutParams.FILL_PARENT, 64 );           TextView text = new  TextView(activity);           text.setLayoutParams(layoutParams);           // Center the text vertically            text.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);           // Set the text starting position            text.setPadding(36 , 0 , 0 , 0 );           text.setText(string);           return  text;       }       public  boolean  hasStableIds()       {           return  false ;       }       public  boolean  isChildSelectable(int  groupPosition, int  childPosition)       {           return  true ;       }   }

最后，给定义好的ExpandableListView添加上Adapter

ExpandableListView expandableListView = (ExpandableListView)findViewById(R.id.expandableListView);   expandableListView.setAdapter(new  ExpandableAdapter(Main.this ));

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