Getting started with Android: Use the expandablelistview Control

This article describes how to use the expandablelistview control and how to use the expandablelistactivity class and simpleexpandablelistadapter adapter.

The code is described as follows:

First, layout contains three layout files:

Main. xml

<? XML version = "1.0" encoding = "UTF-8"?>
<Linearlayout xmlns: Android = "http://schemas.android.com/apk/res/android"
Android: Orientation = "vertical"
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent"
>
<Expandablelistview
Android: Id = "@ ID/Android: List"
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent"
Android: drawselectid Top = "true"
/> <! -- Android: drawselectid top: whether to highlight -->
<Textview
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent"
Android: text = "no data"
Android: Id = "@ ID/Android: empty"
/>
</Linearlayout>

---------------------------------------------------------------------------

Group. xml

<? XML version = "1.0" encoding = "UTF-8"?>
<Linearlayout xmlns: Android = "http://schemas.android.com/apk/res/android"
Android: Orientation = "vertical"
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent"
>
<Textview
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent"
Android: text = "no data"
Android: Id = "@ + ID/tvgroup"
Android: paddingbottom = "10px"
Android: paddingleft = "50px"

/>
</Linearlayout>

--------------------------------------------------

Child. xml

<? XML version = "1.0" encoding = "UTF-8"?>
<Linearlayout xmlns: Android = "http://schemas.android.com/apk/res/android"
Android: Orientation = "vertical"
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent"
>
 
<Textview
Android: layout_width = "fill_parent"
Android: layout_height = "wrap_content"
Android: text = "no data"
Android: Id = "@ + ID/tvchild"
Android: paddingleft = "50px"
/>
</Linearlayout>

---------------------------------------------------------------------

Java code:

Import java. util. arraylist;
Import java. util. hashmap;
Import java. util. List;
Import java. util. Map;

Import Android. App. expandablelistactivity;
Import Android. OS. Bundle;
Import Android. widget. simpleexpandablelistadapter;

Public class expandablelistactivitytest extends expandablelistactivity {
@ Override
Public void oncreate (bundle savedinstancestate ){
Super. oncreate (savedinstancestate );
Setcontentview (R. layout. Main );

List <Map <string, string> groups = new arraylist <Map <string, string> ();
Map <string, string> group1 = new hashmap <string, string> ();
Group1.put ("group", "huangweiyong ");

Map <string, string> group2 = new hashmap <string, string> ();
Group2.put ("group", "Xiaoqi ");

Map <string, string> Group3 = new hashmap <string, string> ();
Group3.put ("group", "HAHAHA ");

Groups. Add (group1 );
Groups. Add (group2 );
Groups. Add (Group3 );

List <Map <string, string> Child1 = new arraylist <Map <string, string> ();
Map <string, string> child1data1 = new hashmap <string, string> ();
Child1data1. Put ("child", "child1data1 ");
Map <string, string> child1data2 = new hashmap <string, string> ();
Child1data2. Put ("child", "child1data2 ");
Child1.add (child1data1 );
Child1.add (child1data2 );

List <Map <string, string> child2 = new arraylist <Map <string, string> ();
Map <string, string> child2data1 = new hashmap <string, string> ();
Child2data1. Put ("child", "child1data1 ");
Child2.add (child2data1 );

List <Map <string, string> Child3 = new arraylist <Map <string, string> ();
Map <string, string> child3data1 = new hashmap <string, string> ();
Child3data1. Put ("child", "child1data1 ");
Child3.add (child3data1 );

List <list <Map <string, string >>> Childs = new arraylist <list <Map <string, string >>> ();
Childs. Add (Child1 );
Childs. Add (child2 );
Childs. Add (Child3 );

/**
* Generate a simpleexpandablelistadapter object
* 1. Context
* 2. Data of level 1 entries
* 3. Set the layout file for the first-level entry Style
* 4. Specify the key of the first-level entry data
* 5. ID of the control displayed for the first-level entry
* 6. specify data of level 2 entries
* 7. layout file used to set the second-level entry Style
* 8. Specify the key of the second-level entry data
* 9. ID of the control displayed for the specified second-level entry data
*/
Simpleexpandablelistadapter SELA = new simpleexpandablelistadapter (
This, groups, R. layout. Group, New String [] {"group "},
New int [] {R. Id. tvgroup}, Childs, R. layout. Child,
New String [] {"child"}, new int [] {R. Id. tvchild });
// Set the adapter object to expandablelistactivity
Setlistadapter (SELA );
}
}