Added in API level 1
Deprecated in API level 30

ExpandableListActivity


open class ExpandableListActivity : Activity, View.OnCreateContextMenuListener, ExpandableListView.OnChildClickListener, ExpandableListView.OnGroupCollapseListener, ExpandableListView.OnGroupExpandListener
kotlin.Any
   ↳ android.content.Context
   ↳ android.content.ContextWrapper
   ↳ android.view.ContextThemeWrapper
   ↳ android.app.Activity
   ↳ android.app.ExpandableListActivity

An activity that displays an expandable list of items by binding to a data source implementing the ExpandableListAdapter, and exposes event handlers when the user selects an item.

ExpandableListActivity hosts a ExpandableListView object that can be bound to different data sources that provide a two-levels of data (the top-level is group, and below each group are children). Binding, screen layout, and row layout are discussed in the following sections.

Screen Layout

ExpandableListActivity has a default layout that consists of a single, full-screen, centered expandable list. However, if you desire, you can customize the screen layout by setting your own view layout with setContentView() in onCreate(). To do this, your own view MUST contain an ExpandableListView object with the id "@android:id/list" (or android.R.id#list if it's in code)

Optionally, your custom view can contain another view object of any type to display when the list view is empty. This "empty list" notifier must have an id "android:empty". Note that when an empty view is present, the expandable list view will be hidden when there is no data to display.

The following code demonstrates an (ugly) custom screen layout. It has a list with a green background, and an alternate red "no data" message.

<?xml version="1.0" encoding="UTF-8"?>
  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
          android:orientation="vertical"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:paddingLeft="8dp"
          android:paddingRight="8dp">
 
      <ExpandableListView android:id="@id/android:list"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="#00FF00"
                android:layout_weight="1"
                android:drawSelectorOnTop="false"/>
 
      <TextView android:id="@id/android:empty"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="#FF0000"
                android:text="No data"/>
  </LinearLayout>
  

Row Layout

The ExpandableListAdapter set in the ExpandableListActivity via setListAdapter(android.widget.ExpandableListAdapter) provides the Views for each row. This adapter has separate methods for providing the group Views and child Views. There are a couple provided ExpandableListAdapters that simplify use of adapters: SimpleCursorTreeAdapter and SimpleExpandableListAdapter.

With these, you can specify the layout of individual rows for groups and children in the list. These constructor takes a few parameters that specify layout resources for groups and children. It also has additional parameters that let you specify which data field to associate with which object in the row layout resource. The SimpleCursorTreeAdapter fetches data from Cursors and the SimpleExpandableListAdapter fetches data from Lists of Maps.

Android provides some standard row layout resources. These are in the android.R.layout class, and have names such as simple_list_item_1, simple_list_item_2, and two_line_list_item. The following layout XML is the source for the resource two_line_list_item, which displays two data fields,one above the other, for each list row.

<?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="wrap_content"
      android:orientation="vertical">
 
      <TextView android:id="@+id/text1"
          android:textSize="16sp"
          android:textStyle="bold"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"/>
 
      <TextView android:id="@+id/text2"
          android:textSize="16sp"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"/>
  </LinearLayout>
  

You must identify the data bound to each TextView object in this layout. The syntax for this is discussed in the next section.

Binding to Data

You bind the ExpandableListActivity's ExpandableListView object to data using a class that implements the ExpandableListAdapter interface. Android provides two standard list adapters: SimpleExpandableListAdapter for static data (Maps), and SimpleCursorTreeAdapter for Cursor query results.

Summary

Inherited constants
Public constructors

Public methods
open ExpandableListAdapter!

Get the ExpandableListAdapter associated with this activity's ExpandableListView.

open ExpandableListView!

Get the activity's expandable list view widget.

open Long

Gets the ID of the currently selected group or child.

open Long

Gets the position (in packed position representation) of the currently selected group or child.

open Boolean
onChildClick(parent: ExpandableListView!, v: View!, groupPosition: Int, childPosition: Int, id: Long)

Override this for receiving callbacks when a child has been clicked.

open Unit

Updates the screen state (current list and other views) when the content changes.

open Unit

Override this to populate the context menu when an item is long pressed.

open Unit
onGroupCollapse(groupPosition: Int)

Override this for receiving callbacks when a group has been collapsed.

open Unit
onGroupExpand(groupPosition: Int)

Override this for receiving callbacks when a group has been expanded.

open Unit

Provide the adapter for the expandable list.

open Boolean
setSelectedChild(groupPosition: Int, childPosition: Int, shouldExpandGroup: Boolean)

Sets the selection to the specified child.

open Unit
setSelectedGroup(groupPosition: Int)

Sets the selection to the specified group.

Protected methods
open Unit

Ensures the expandable list view has been created before Activity restores all of the view states.

Inherited functions
Inherited properties

Public constructors

ExpandableListActivity

ExpandableListActivity()

Public methods

getExpandableListAdapter

Added in API level 1
open fun getExpandableListAdapter(): ExpandableListAdapter!

Deprecated: Deprecated in Java.

Get the ExpandableListAdapter associated with this activity's ExpandableListView.

getExpandableListView

Added in API level 1
open fun getExpandableListView(): ExpandableListView!

Deprecated: Deprecated in Java.

Get the activity's expandable list view widget. This can be used to get the selection, set the selection, and many other useful functions.

getSelectedId

Added in API level 1
open fun getSelectedId(): Long

Deprecated: Deprecated in Java.

Gets the ID of the currently selected group or child.

Return
Long The ID of the currently selected group or child.

getSelectedPosition

Added in API level 1
open fun getSelectedPosition(): Long

Deprecated: Deprecated in Java.

Gets the position (in packed position representation) of the currently selected group or child. Use ExpandableListView#getPackedPositionType, ExpandableListView#getPackedPositionGroup, and ExpandableListView#getPackedPositionChild to unpack the returned packed position.

Return
Long A packed position representation containing the currently selected group or child's position and type.

onChildClick

Added in API level 1
open fun onChildClick(
    parent: ExpandableListView!,
    v: View!,
    groupPosition: Int,
    childPosition: Int,
    id: Long
): Boolean

Deprecated: Deprecated in Java.

Override this for receiving callbacks when a child has been clicked.

Callback method to be invoked when a child in this expandable list has been clicked.

Parameters
parent ExpandableListView!: The ExpandableListView where the click happened
v View!: The view within the expandable list/ListView that was clicked
groupPosition Int: The group position that contains the child that was clicked
childPosition Int: The child position within the group
id Long: The row id of the child that was clicked
Return
Boolean True if the click was handled

onContentChanged

Added in API level 1
open fun onContentChanged(): Unit

Deprecated: Deprecated in Java.

Updates the screen state (current list and other views) when the content changes.

onCreateContextMenu

Added in API level 1
open fun onCreateContextMenu(
    menu: ContextMenu!,
    v: View!,
    menuInfo: ContextMenu.ContextMenuInfo!
): Unit

Deprecated: Deprecated in Java.

Override this to populate the context menu when an item is long pressed. menuInfo will contain an android.widget.ExpandableListView.ExpandableListContextMenuInfo whose packedPosition is a packed position that should be used with ExpandableListView#getPackedPositionType(long) and the other similar methods.

Called when a context menu for the view is about to be shown. Unlike onCreateOptionsMenu(android.view.Menu), this will be called every time the context menu is about to be shown and should be populated for the view (or item inside the view for AdapterView subclasses, this can be found in the menuInfo)).

Use onContextItemSelected(android.view.MenuItem) to know when an item has been selected.

It is not safe to hold onto the context menu after this method returns.

Parameters
menu ContextMenu!: The context menu that is being built
v View!: The view for which the context menu is being built
menuInfo ContextMenu.ContextMenuInfo!: Extra information about the item for which the context menu should be shown. This information will vary depending on the class of v.

onGroupCollapse

Added in API level 1
open fun onGroupCollapse(groupPosition: Int): Unit

Deprecated: Deprecated in Java.

Override this for receiving callbacks when a group has been collapsed.

Parameters
groupPosition Int: The group position that was collapsed

onGroupExpand

Added in API level 1
open fun onGroupExpand(groupPosition: Int): Unit

Deprecated: Deprecated in Java.

Override this for receiving callbacks when a group has been expanded.

Parameters
groupPosition Int: The group position that was expanded

setListAdapter

Added in API level 1
open fun setListAdapter(adapter: ExpandableListAdapter!): Unit

Deprecated: Deprecated in Java.

Provide the adapter for the expandable list.

setSelectedChild

Added in API level 1
open fun setSelectedChild(
    groupPosition: Int,
    childPosition: Int,
    shouldExpandGroup: Boolean
): Boolean

Deprecated: Deprecated in Java.

Sets the selection to the specified child. If the child is in a collapsed group, the group will only be expanded and child subsequently selected if shouldExpandGroup is set to true, otherwise the method will return false.

Parameters
groupPosition Int: The position of the group that contains the child.
childPosition Int: The position of the child within the group.
shouldExpandGroup Boolean: Whether the child's group should be expanded if it is collapsed.
Return
Boolean Whether the selection was successfully set on the child.

setSelectedGroup

Added in API level 1
open fun setSelectedGroup(groupPosition: Int): Unit

Deprecated: Deprecated in Java.

Sets the selection to the specified group.

Parameters
groupPosition Int: The position of the group that should be selected.

Protected methods

onRestoreInstanceState

Added in API level 1
protected open fun onRestoreInstanceState(state: Bundle): Unit

Deprecated: Deprecated in Java.

Ensures the expandable list view has been created before Activity restores all of the view states.

Parameters
savedInstanceState the data most recently supplied in #onSaveInstanceState. This value cannot be null.