Kotlin ExpandableListView可扩展二级列表，大厂安卓面试真题精选

groupName.add(“统计1”)

groupName.add(“统计2”)

return groupName

}

…

3.1 StatisticsAdapter.kt

3.1.1 RootNodeProvider.kt，点击item

override fun onClick(helper: BaseViewHolder, view: View, data: BaseNode, position: Int) {

getAdapter()!!.expandOrCollapse(position)

}

3.1.2 StatisticsNodeProvider.kt

override fun onClick(helper: BaseViewHolder, view: View, data: BaseNode, position: Int) {

val entity: StatisticsNode = data as Stati
sticsNode

if (“2” == entity.classity) {

val intent = Intent(MyApplication.context, StatisticsActivity::class.java)

context?.startActivity(intent)

}

4.activity_expandable_listview.xml，这是扩展二级列表的

…

<ExpandableListView

android:id="@+id/elvContent"

android:layout_width=“match_parent”

android:layout_height=“match_parent”

android:groupIndicator="@null" />

…

5.StatisticsActivity.kt

5.1

fun initView() {

adapter = DetailExpandableListAdapter(this)

elvContent.setAdapter(adapter)

}

5.2 可以自己设置数据，注意：必须要有规律,代码(注释说明)如下

fun initDatas() {

//"1"表示标题

var sc = SitCode(1, “1”, “一栋宿舍”);list.add(sc)

//"1A"表示第一组

sc = SitCode(2, “1A”, “宿舍2001”);list.add(sc)

//“1AA”,“1AB”,“1AC”,"1AD"表示子选项

sc = SitCode(3, “1AA”, “小红”);list.add(sc)

sc = SitCode(4, “1AB”, “小彬”);list.add(sc)

sc = SitCode(5, “1AC”, “小强”);list.add(sc)

sc = SitCode(6, “1AD”, “小红”);list.add(sc)

//"1B"表示第二组

sc = SitCode(7, “1B”, “宿舍2002”);list.add(sc)

//“1BA”,"1BB"表示子选项

sc = SitCode(8, “1BA”, “小可”);list.add(sc)

sc = SitCode(9, “1BB”, “小雪”);list.add(sc)

sc = SitCode(10, “1BC”, “小飞”);list.add(sc)

//"1C"表示第三组

sc = SitCode(11, “1C”, “宿舍2003”);list.add(sc)

//“1CA”,“1CB”,"1CC"表示子选项

sc = SitCode(12, “1CA”, “小和”);list.add(sc)

sc = SitCode(13, “1CB”, “小杨”);list.add(sc)

sc = SitCode(14, “1CC”, “小一”);list.add(sc)

//"1D"表示第四组

sc = SitCode(15, “1D”, “宿舍2004”);list.add(sc)

//"2"表示标题

sc = SitCode(16, “2”, “二栋宿舍”);list.add(sc)

//"2A"表示第五组

sc = SitCode(17, “2A”, “宿舍2005”);list.add(sc)

//"2B"表示第六组

sc = SitCode(18, “2B”, “宿舍2006”);list.add(sc)

//“2BA”,“2BB”,"1CC"表示子选项

sc = SitCode(19, “2BA”, “小山”);list.add(sc)

sc = SitCode(20, “2BB”, “小梅”);list.add(sc)

//"2C"表示第七组

sc = SitCode(21, “2C”, “宿舍2007”);list.add(sc)

//"3"表示标题

sc = SitCode(22, “3”, “三栋宿舍”);list.add(sc)

//"3A"表示第八组

sc = SitCode(23, “3A”, “宿舍2008”);list.add(sc)

//"3B"表示第九组

sc = SitCode(24, “3B”, “宿舍2009”);list.add(sc)

//"3C"表示第十组

sc = SitCode(25, “3C”, “宿舍2010”);list.add(sc)

//"4"表示标题

sc = SitCode(26, “4”, “四栋宿舍”);list.add(sc)

…

5.2.1 我做开发时就用sqlite数据库上设置数据比较好，需要和SQL Server一致，如下图

如何用代码获取sqlite数据库的数据，你需要的话，可以点击

Kotlin开发如何获取SQLite数据库上自己创建规律的可扩展二级列表数据

5.3 代码(注释说明)如下

…

for (sitcode in list) {

val code = sitcode.code

//如果code是“1”或者“1A”或者“1AB”

when (code.length) {

//组数据给groups,groups包括有标题和组

//"1"的长度是1就给groups赋值

1 -> groups.add(sitcode)

//"1A"的长度是2就给groups赋值

2 -> groups.add(sitcode)

else -> {

//1AB(子选项)的长度是3就给对应的group赋值

val groupCode = code.substring(0, 2)

var childs = groupChilds[groupCode]

if (childs == null) {

childs = ArrayList()

groupChilds[groupCode] = childs

}

childs.add(sitcode)

}

…

5.4 获取指定组位置处的组数据

override fun getGroupView(groupPosition: Int, isExpanded: Boolean, convertView: View?, parent: ViewGroup?): View {

var convertView = convertView

var viewHolder: ViewHolder = ViewHolder.getViewHolder(inflater, convertView, parent, R.layout.item_ser_detail)

val sitCode = getGroup(groupPosition)

convertView = viewHolder.convertView

val iv: ImageView = viewHolder.getView(R.id.iv_ser) as ImageView

//如果sitCode.code=“1A”(组)

if (sitCode.code.length == 2){

//如果“1A”有子选项“1AA”

if (list[sitCode.id].code.length == 3 ){

//把箭头开了

iv.visibility = View.VISIBLE

}

}else{

//如果“1A”没有子选项，箭头就隐去

iv.visibility = View.GONE

}

er.convertView