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ExpandableListView组件是android中一个比较常用的组件,当点击一个父item的时候可以将它的子item显示出来,像手机QQ中的好友列表就是实现的类型效果。使用ExpandableListView组件的关键就是设置它的adapter,这个adapter必须继承BaseExpandbaleListAdapter类,所以实现运用ExpandableListView的核心就是学会继承这个BaseExpanableListAdapter类。
下面是一个小demo:
activvity_main.xml:
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<
RelativeLayout
xmlns:android
=
"http://schemas.android.com/apk/res/android"
xmlns:tools
=
"http://schemas.android.com/tools"
android:layout_width
=
"match_parent"
android:layout_height
=
"match_parent"
tools:context
=
".MainActivity"
>
<
ExpandableListView
android:id
=
"@+id/main_expandablelistview"
android:layout_width
=
"match_parent"
android:layout_height
=
"wrap_content"
/>
</
RelativeLayout
>
|
layout_parent.xml:(父item运用的样式)
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<?
xml
version
=
"1.0"
encoding
=
"utf-8"
?>
<
LinearLayout
xmlns:android
=
"http://schemas.android.com/apk/res/android"
android:layout_width
=
"match_parent"
android:layout_height
=
"match_parent"
android:orientation
=
"vertical"
>
<
TextView
android:id
=
"@+id/parent_textview"
android:layout_width
=
"match_parent"
android:layout_height
=
"50dp"
android:layout_gravity
=
"center"
android:gravity
=
"center"
/>
</
LinearLayout
>
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layout_children.xml:(子item运用的样式)
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<?
xml
version
=
"1.0"
encoding
=
"utf-8"
?>
<
LinearLayout
xmlns:android
=
"http://schemas.android.com/apk/res/android"
android:layout_width
=
"match_parent"
android:layout_height
=
"match_parent"
android:orientation
=
"vertical"
>
<
TextView
android:id
=
"@+id/second_textview"
android:layout_width
=
"match_parent"
android:layout_height
=
"40dp"
android:layout_gravity
=
"center"
android:gravity
=
"center"
/>
</
LinearLayout
>
|
MainActivity.java:
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package
com.example.android_expandablelistview;
import
java.util.ArrayList;
import
java.util.HashMap;
import
java.util.List;
import
java.util.Map;
import
android.app.Activity;
import
android.content.Context;
import
android.os.Bundle;
import
android.view.LayoutInflater;
import
android.view.View;
import
android.view.ViewGroup;
import
android.widget.BaseExpandableListAdapter;
import
android.widget.ExpandableListView;
import
android.widget.TextView;
public
class
MainActivity
extends
Activity {
ExpandableListView mainlistview =
null
;
List<String> parent =
null
;
Map<String, List<String>> map =
null
;
@Override
protected
void
onCreate(Bundle savedInstanceState) {
super
.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainlistview = (ExpandableListView)
this
.findViewById(R.id.main_expandablelistview);
initData();
mainlistview.setAdapter(
new
MyAdapter());
}
// 初始化数据
public
void
initData() {
parent =
new
ArrayList<String>();
parent.add(
"parent1"
);
parent.add(
"parent2"
);
parent.add(
"parent3"
);
map =
new
HashMap<String, List<String>>();
List<String> list1 =
new
ArrayList<String>();
list1.add(
"child1-1"
);
list1.add(
"child1-2"
);
list1.add(
"child1-3"
);
map.put(
"parent1"
, list1);
List<String> list2 =
new
ArrayList<String>();
list2.add(
"child2-1"
);
list2.add(
"child2-2"
);
list2.add(
"child2-3"
);
map.put(
"parent2"
, list2);
List<String> list3 =
new
ArrayList<String>();
list3.add(
"child3-1"
);
list3.add(
"child3-2"
);
list3.add(
"child3-3"
);
map.put(
"parent3"
, list3);
}
class
MyAdapter
extends
BaseExpandableListAdapter {
//得到子item需要关联的数据
@Override
public
Object getChild(
int
groupPosition,
int
childPosition) {
String key = parent.get(groupPosition);
return
(map.get(key).get(childPosition));
}
//得到子item的ID
@Override
public
long
getChildId(
int
groupPosition,
int
childPosition) {
return
childPosition;
}
//设置子item的组件
@Override
public
View getChildView(
int
groupPosition,
int
childPosition,
boolean
isLastChild, View convertView, ViewGroup parent) {
String key = MainActivity.
this
.parent.get(groupPosition);
String info = map.get(key).get(childPosition);
if
(convertView ==
null
) {
LayoutInflater inflater = (LayoutInflater) MainActivity.
this
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.layout_children,
null
);
}
TextView tv = (TextView) convertView
.findViewById(R.id.second_textview);
tv.setText(info);
return
tv;
}
//获取当前父item下的子item的个数
@Override
public
int
getChildrenCount(
int
groupPosition) {
String key = parent.get(groupPosition);
int
size=map.get(key).size();
return
size;
}
//获取当前父item的数据
@Override
public
Object getGroup(
int
groupPosition) {
return
parent.get(groupPosition);
}
@Override
public
int
getGroupCount() {
return
parent.size();
}
@Override
public
long
getGroupId(
int
groupPosition) {
return
groupPosition;
}
//设置父item组件
@Override
public
View getGroupView(
int
groupPosition,
boolean
isExpanded,
View convertView, ViewGroup parent) {
if
(convertView ==
null
) {
LayoutInflater inflater = (LayoutInflater) MainActivity.
this
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.layout_parent,
null
);
}
TextView tv = (TextView) convertView
.findViewById(R.id.parent_textview);
tv.setText(MainActivity.
this
.parent.get(groupPosition));
return
tv;
}
@Override
public
boolean
hasStableIds() {
return
true
;
}
@Override
public
boolean
isChildSelectable(
int
groupPosition,
int
childPosition) {
return
true
;
}
}
}
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最后的实现结果: