Android中多级列表可以使用ExpandableListView和SimpleExpandableListAdapter配合来实现，但是，SimpleExpandableListAdapter用起来挺麻烦的，不易理解，而且扩展性也不好，因此，自定义BaseExpandableListAdapter类的子类以及封装相关的操作，用起来会更加直观和方便，我把我设计的封装贴出来供新手参考吧。
首先上效果图，如图所示：
1. 首先设计多级列表的标题类
就像文件和文件夹可以统一地用File类来抽象一样，多级列表的一级标题和二级标题其实也可以用同一个基类来抽象，因此，我设计了一个基类和两个子类，GroupList，GroupListChild 和 GroupListParent，其实现如下所示：
（1） GroupList 多级列表标题的抽象基类
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public
abstract
class
GroupList {
private
final
String mTitle;
public
GroupList(String title) {
mTitle = title;
}
public
String getTitle() {
return
mTitle;
}
public
abstract
List<GroupList> getChild();
public
abstract
int
getResource();
public
abstract
void
buildView(View v);
}
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（2） GroupListChild 多级列表二级标题子类
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public
class
GroupListChild
extends
GroupList {
public
GroupListChild(String title) {
super
(title);
}
@Override
public
int
getResource() {
return
R.layout.grouplist_child;
}
@Override
public
List<GroupList> getChild() {
return
null
;
}
@Override
public
void
buildView(View v) {
TextView textView = (TextView)v.findViewById(R.id.GroupListChild);
textView.setText(getTitle());
}
}
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（3） GroupListParent 多级列表一级标题子类
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public
class
GroupListParent
extends
GroupList {
private
List<GroupList> mPopListChilds;
public
GroupListParent(String title,List<GroupList> childs) {
super
(title);
mPopListChilds = childs;
}
@Override
public
int
getResource() {
return
R.layout.grouplist_parent;
}
@Override
public
List<GroupList> getChild() {
return
mPopListChilds;
}
@Override
public
void
buildView(View v) {
TextView textView = (TextView)v.findViewById(R.id.GroupListParent);
textView.setText(getTitle());
}
}
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2. 设计BaseExpandableListAdapter的子类
我设计的子类是一种通用的Adapter子类，类的实现中并不包含具体的Layout实现，所有的Layout都由GroupList的getResource和buildView来负责，因此，可以非常灵活地修改Layout的具体实现，而不用修改Adapter的代码。
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public
class
GroupListAdapter
extends
BaseExpandableListAdapter {
private
Context mContext;
private
List<GroupList> mGroups;
public
GroupListAdapter(Context context, List<GroupList> groups) {
this
.mContext = context;
this
.mGroups = groups;
}
@Override
public
Object getChild(
int
groupPosition,
int
childPosition) {
List<GroupList> chList = mGroups.get(groupPosition).getChild();
if
( chList ==
null
) {
return
null
;
}
return
chList.get(childPosition);
}
@Override
public
long
getChildId(
int
groupPosition,
int
childPosition) {
return
childPosition;
}
@Override
public
View getChildView(
int
groupPosition,
int
childPosition,
boolean
isLastChild, View view,ViewGroup parent) {
GroupList child = (GroupList)getChild(groupPosition, childPosition);
if
( child ==
null
) {
return
null
;
}
if
(view ==
null
) {
LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = (RelativeLayout)inflater.inflate(child.getResource(),
null
);
}
child.buildView(view);
return
view;
}
@Override
public
int
getChildrenCount(
int
groupPosition) {
List<GroupList> chList = mGroups.get(groupPosition).getChild();
if
( chList ==
null
) {
return
0
;
}
return
chList.size();
}
@Override
public
Object getGroup(
int
groupPosition) {
return
mGroups.get(groupPosition);
}
@Override
public
int
getGroupCount() {
return
mGroups.size();
}
@Override
public
long
getGroupId(
int
groupPosition) {
return
groupPosition;
}
@Override
public
View getGroupView(
int
groupPosition,
boolean
isLastChild, View view,ViewGroup parent) {
GroupList group = (GroupList)getGroup(groupPosition);
if
(view ==
null
) {
LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = (RelativeLayout)inflater.inflate(group.getResource(),
null
);
}
group.buildView(view);
return
view;
}
@Override
public
boolean
hasStableIds() {
return
true
;
}
@Override
public
boolean
isChildSelectable(
int
arg0,
int
arg1) {
return
true
;
}
}
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3. 应用代码
为了简化，我就直接在MainActivity中使用上述封装的类来完成多级列表的功能演示，示例如下：
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public
class
MainActivity
extends
Activity
implements
OnGroupClickListener,OnChildClickListener {
private
ExpandableListView mlistView;
private
GroupListAdapter mAdapter;
private
static
final
String[] mParentMenu = {
"Book"
,
"Video"
,
"Audio"
};
private
static
final
String[][] mChildMenu = {
{
"book1"
,
"book2"
,
"book3"
,
"book4"
},
{
"video1"
,
"video2"
},
{
"audio1"
,
"audio2"
,
"audio3"
,
"audio4"
}
};
@Override
protected
void
onCreate(Bundle savedInstanceState) {
super
.onCreate(savedInstanceState);
mlistView =
new
ExpandableListView(
this
);
mlistView.setOnGroupClickListener(
this
);
mlistView.setOnChildClickListener(
this
);
List<GroupList> groups =
new
ArrayList<GroupList>();
for
(
int
i=
0
; i<mParentMenu.length; i++) {
List<GroupList> childs =
new
ArrayList<GroupList>();
for
(
int
j=
0
; j<mChildMenu[i].length; j++ ) {
childs.add(
new
GroupListChild(mChildMenu[i][j]));
}
groups.add(
new
GroupListParent(mParentMenu[i],childs));
}
mAdapter =
new
GroupListAdapter(
this
,groups);
mlistView.setAdapter(mAdapter);
setContentView(mlistView);
}
@Override
public
boolean
onChildClick(ExpandableListView parent, View v,
int
groupPosition,
int
childPosition,
long
id) {
return
false
;
}
@Override
public
boolean
onGroupClick(ExpandableListView parent, View v,
int
groupPosition,
long
id) {
return
false
;
}
}
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4. 相关的xml文件
（1） grouplist_child.xml 文件
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<?
xml
version
=
"1.0"
encoding
=
"utf-8"
?>
<
RelativeLayout
xmlns:android
=
"http://schemas.android.com/apk/res/android"
android:layout_width
=
"match_parent"
android:layout_height
=
"match_parent"
android:orientation
=
"horizontal"
>
<
TextView
android:id
=
"@+id/GroupListChild"
android:layout_width
=
"wrap_content"
android:layout_height
=
"wrap_content"
android:textColor
=
"#FFFF0000"
android:layout_margin
=
"10dp"
android:layout_centerInParent
=
"true"
/>
</
RelativeLayout
>
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（2） grouplist_parent.xml 文件
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<?
xml
version
=
"1.0"
encoding
=
"utf-8"
?>
<
RelativeLayout
xmlns:android
=
"http://schemas.android.com/apk/res/android"
android:layout_width
=
"match_parent"
android:layout_height
=
"match_parent"
android:orientation
=
"horizontal"
>
<
TextView
android:id
=
"@+id/GroupListParent"
android:layout_width
=
"wrap_content"
android:layout_height
=
"wrap_content"
android:textColor
=
"@android:color/black"
android:textStyle
=
"bold"
android:layout_margin
=
"10dp"
android:layout_centerInParent
=
"true"
/>
</
RelativeLayout
>
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本文转自 Jhuster 51CTO博客，原文链接：http://blog.51cto.com/ticktick/1289642，如需转载请自行联系原作者
