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 ));