public class ExpandableListActivity extends Activity implements View.OnCreateContextMenuListener, ExpandableListView.OnChildClickListener, ExpandableListView.OnGroupCollapseListener, ExpandableListView.OnGroupExpandListener
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
TheExpandableListAdapter
set in the ExpandableListActivity
via setListAdapter(ExpandableListAdapter)
provides the View
s
for each row. This adapter has separate methods for providing the group
View
s and child View
s. There are a couple provided
ExpandableListAdapter
s 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
Cursor
s and the SimpleExpandableListAdapter
fetches data
from List
s of Map
s.
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.
DEFAULT_KEYS_DIALER, DEFAULT_KEYS_DISABLE, DEFAULT_KEYS_SEARCH_GLOBAL, DEFAULT_KEYS_SEARCH_LOCAL, DEFAULT_KEYS_SHORTCUT, FOCUSED_STATE_SET, RESULT_CANCELED, RESULT_FIRST_USER, RESULT_OK
ACCESSIBILITY_SERVICE, ACCOUNT_SERVICE, ACTIVITY_SERVICE, ALARM_SERVICE, APPWIDGET_SERVICE, AUDIO_SERVICE, BACKUP_SERVICE, BIND_ABOVE_CLIENT, BIND_ADJUST_WITH_ACTIVITY, BIND_ALLOW_OOM_MANAGEMENT, BIND_AUTO_CREATE, BIND_DEBUG_UNBIND, BIND_IMPORTANT, BIND_NOT_FOREGROUND, BIND_NOT_VISIBLE, BIND_VISIBLE, BIND_WAIVE_PRIORITY, BLUETOOTH_SERVICE, CLIPBOARD_SERVICE, CONNECTIVITY_SERVICE, CONTEXT_IGNORE_SECURITY, CONTEXT_INCLUDE_CODE, CONTEXT_RESTRICTED, COUNTRY_DETECTOR, DEVICE_POLICY_SERVICE, DISPLAY_SERVICE, DOWNLOAD_SERVICE, DROPBOX_SERVICE, INPUT_METHOD_SERVICE, INPUT_SERVICE, KEYGUARD_SERVICE, LAYOUT_INFLATER_SERVICE, LOCATION_SERVICE, MEDIA_ROUTER_SERVICE, MODE_APPEND, MODE_ENABLE_WRITE_AHEAD_LOGGING, MODE_MULTI_PROCESS, MODE_PRIVATE, MODE_WORLD_READABLE, MODE_WORLD_WRITEABLE, NETWORK_POLICY_SERVICE, NETWORK_STATS_SERVICE, NETWORKMANAGEMENT_SERVICE, NFC_SERVICE, NOTIFICATION_SERVICE, NSD_SERVICE, POWER_SERVICE, SCHEDULING_POLICY_SERVICE, SEARCH_SERVICE, SENSOR_SERVICE, SERIAL_SERVICE, SIP_SERVICE, STATUS_BAR_SERVICE, STORAGE_SERVICE, TELEPHONY_SERVICE, TEXT_SERVICES_MANAGER_SERVICE, THROTTLE_SERVICE, UI_MODE_SERVICE, UPDATE_LOCK_SERVICE, USB_SERVICE, USER_SERVICE, VIBRATOR_SERVICE, WALLPAPER_SERVICE, WIFI_P2P_SERVICE, WIFI_SERVICE, WINDOW_SERVICE
TRIM_MEMORY_BACKGROUND, TRIM_MEMORY_COMPLETE, TRIM_MEMORY_MODERATE, TRIM_MEMORY_RUNNING_CRITICAL, TRIM_MEMORY_RUNNING_LOW, TRIM_MEMORY_RUNNING_MODERATE, TRIM_MEMORY_UI_HIDDEN
Constructor and Description |
---|
ExpandableListActivity() |
Modifier and Type | Method and Description |
---|---|
ExpandableListAdapter |
getExpandableListAdapter()
Get the ExpandableListAdapter associated with this activity's
ExpandableListView.
|
ExpandableListView |
getExpandableListView()
Get the activity's expandable list view widget.
|
long |
getSelectedId()
Gets the ID of the currently selected group or child.
|
long |
getSelectedPosition()
Gets the position (in packed position representation) of the currently
selected group or child.
|
boolean |
onChildClick(ExpandableListView parent,
View v,
int groupPosition,
int childPosition,
long id)
Override this for receiving callbacks when a child has been clicked.
|
void |
onContentChanged()
Updates the screen state (current list and other views) when the
content changes.
|
void |
onCreateContextMenu(ContextMenu menu,
View v,
ContextMenu.ContextMenuInfo menuInfo)
Override this to populate the context menu when an item is long pressed.
|
void |
onGroupCollapse(int groupPosition)
Override this for receiving callbacks when a group has been collapsed.
|
void |
onGroupExpand(int groupPosition)
Override this for receiving callbacks when a group has been expanded.
|
protected void |
onRestoreInstanceState(Bundle state)
Ensures the expandable list view has been created before Activity restores all
of the view states.
|
void |
setListAdapter(ExpandableListAdapter adapter)
Provide the adapter for the expandable list.
|
boolean |
setSelectedChild(int groupPosition,
int childPosition,
boolean shouldExpandGroup)
Sets the selection to the specified child.
|
void |
setSelectedGroup(int groupPosition)
Sets the selection to the specified group.
|
addContentView, closeContextMenu, closeOptionsMenu, createPendingResult, dismissDialog, dispatchGenericMotionEvent, dispatchKeyEvent, dispatchKeyShortcutEvent, dispatchPopulateAccessibilityEvent, dispatchTouchEvent, dispatchTrackballEvent, dump, findViewById, finish, finishActivity, finishActivityFromChild, finishAffinity, finishFromChild, getActionBar, getActivityToken, getApplication, getCallingActivity, getCallingPackage, getChangingConfigurations, getComponentName, getCurrentFocus, getFragmentManager, getIntent, getLastNonConfigurationInstance, getLayoutInflater, getLoaderManager, getLocalClassName, getMenuInflater, getParent, getParentActivityIntent, getPreferences, getRequestedOrientation, getSystemService, getTaskId, getTitle, getTitleColor, getVolumeControlStream, getWindow, getWindowManager, hasWindowFocus, invalidateOptionsMenu, isChangingConfigurations, isChild, isDestroyed, isFinishing, isImmersive, isResumed, isTaskRoot, managedQuery, managedQuery, moveTaskToBack, navigateUpTo, navigateUpToFromChild, onActionModeFinished, onActionModeStarted, onActivityResult, onApplyThemeResource, onAttachedToWindow, onAttachFragment, onBackPressed, onChildTitleChanged, onConfigurationChanged, onContextItemSelected, onContextMenuClosed, onCreate, onCreateDescription, onCreateDialog, onCreateDialog, onCreateNavigateUpTaskStack, onCreateOptionsMenu, onCreatePanelMenu, onCreatePanelView, onCreateThumbnail, onCreateView, onCreateView, onDestroy, onDetachedFromWindow, onGenericMotionEvent, onKeyDown, onKeyLongPress, onKeyMultiple, onKeyShortcut, onKeyUp, onLowMemory, onMenuItemSelected, onMenuOpened, onNavigateUp, onNavigateUpFromChild, onNewIntent, onOptionsItemSelected, onOptionsMenuClosed, onPanelClosed, onPause, onPostCreate, onPostResume, onPrepareDialog, onPrepareDialog, onPrepareNavigateUpTaskStack, onPrepareOptionsMenu, onPreparePanel, onRestart, onResume, onRetainNonConfigurationInstance, onSaveInstanceState, onSearchRequested, onStart, onStop, onTitleChanged, onTouchEvent, onTrackballEvent, onTrimMemory, onUserInteraction, onUserLeaveHint, onWindowAttributesChanged, onWindowFocusChanged, onWindowStartingActionMode, openContextMenu, openOptionsMenu, overridePendingTransition, recreate, registerForContextMenu, removeDialog, requestWindowFeature, runOnUiThread, setContentView, setContentView, setContentView, setDefaultKeyMode, setFeatureDrawable, setFeatureDrawableAlpha, setFeatureDrawableResource, setFeatureDrawableUri, setFinishOnTouchOutside, setImmersive, setIntent, setPersistent, setProgress, setProgressBarIndeterminate, setProgressBarIndeterminateVisibility, setProgressBarVisibility, setRequestedOrientation, setResult, setResult, setSecondaryProgress, setTitle, setTitle, setTitleColor, setVisible, setVolumeControlStream, shouldUpRecreateTask, showDialog, showDialog, startActionMode, startActivities, startActivities, startActivity, startActivity, startActivityAsUser, startActivityAsUser, startActivityForResult, startActivityForResult, startActivityFromChild, startActivityFromChild, startActivityFromFragment, startActivityFromFragment, startActivityIfNeeded, startActivityIfNeeded, startIntentSender, startIntentSender, startIntentSenderForResult, startIntentSenderForResult, startIntentSenderFromChild, startIntentSenderFromChild, startManagingCursor, startNextMatchingActivity, startNextMatchingActivity, startSearch, stopManagingCursor, takeKeyEvents, triggerSearch, unregisterForContextMenu
applyOverrideConfiguration, attachBaseContext, getResources, getTheme, getThemeResId, setTheme
bindService, bindService, checkCallingOrSelfPermission, checkCallingOrSelfUriPermission, checkCallingPermission, checkCallingUriPermission, checkPermission, checkUriPermission, checkUriPermission, clearWallpaper, createConfigurationContext, createDisplayContext, createPackageContext, createPackageContextAsUser, databaseList, deleteDatabase, deleteFile, enforceCallingOrSelfPermission, enforceCallingOrSelfUriPermission, enforceCallingPermission, enforceCallingUriPermission, enforcePermission, enforceUriPermission, enforceUriPermission, fileList, getApplicationContext, getApplicationInfo, getAssets, getBaseContext, getCacheDir, getClassLoader, getCompatibilityInfo, getContentResolver, getDatabasePath, getDir, getExternalCacheDir, getExternalFilesDir, getFilesDir, getFileStreamPath, getMainLooper, getObbDir, getPackageCodePath, getPackageManager, getPackageName, getPackageResourcePath, getSharedPreferences, getSharedPrefsFile, getWallpaper, getWallpaperDesiredMinimumHeight, getWallpaperDesiredMinimumWidth, grantUriPermission, isRestricted, openFileInput, openFileOutput, openOrCreateDatabase, openOrCreateDatabase, peekWallpaper, registerReceiver, registerReceiver, registerReceiverAsUser, removeStickyBroadcast, removeStickyBroadcastAsUser, revokeUriPermission, sendBroadcast, sendBroadcast, sendBroadcastAsUser, sendBroadcastAsUser, sendOrderedBroadcast, sendOrderedBroadcast, sendOrderedBroadcastAsUser, sendStickyBroadcast, sendStickyBroadcastAsUser, sendStickyOrderedBroadcast, sendStickyOrderedBroadcastAsUser, setWallpaper, setWallpaper, startActivitiesAsUser, startInstrumentation, startService, startServiceAsUser, stopService, stopServiceAsUser, unbindService, unregisterReceiver
getString, getString, getText, obtainStyledAttributes, obtainStyledAttributes, obtainStyledAttributes, obtainStyledAttributes, registerComponentCallbacks, unregisterComponentCallbacks
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo)
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 Activity.onCreateOptionsMenu(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 Activity.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. Called when the context menu for this view is being built. It is not safe to hold onto the menu after this method returns.
onCreateContextMenu
in interface View.OnCreateContextMenuListener
onCreateContextMenu
in class Activity
menu
- The context menu that is being builtv
- The view for which the context menu is being builtmenuInfo
- Extra information about the item for which the
context menu should be shown. This information will vary
depending on the class of v.public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id)
Callback method to be invoked when a child in this expandable list has been clicked.
onChildClick
in interface ExpandableListView.OnChildClickListener
parent
- The ExpandableListView where the click happenedv
- The view within the expandable list/ListView that was clickedgroupPosition
- The group position that contains the child that
was clickedchildPosition
- The child position within the groupid
- The row id of the child that was clickedpublic void onGroupCollapse(int groupPosition)
onGroupCollapse
in interface ExpandableListView.OnGroupCollapseListener
groupPosition
- The group position that was collapsedpublic void onGroupExpand(int groupPosition)
onGroupExpand
in interface ExpandableListView.OnGroupExpandListener
groupPosition
- The group position that was expandedprotected void onRestoreInstanceState(Bundle state)
onRestoreInstanceState
in class Activity
state
- the data most recently supplied in Activity.onSaveInstanceState(android.os.Bundle)
.Activity.onRestoreInstanceState(Bundle)
public void onContentChanged()
onContentChanged
in interface Window.Callback
onContentChanged
in class Activity
Activity.onContentChanged()
public void setListAdapter(ExpandableListAdapter adapter)
public ExpandableListView getExpandableListView()
ExpandableListView
public ExpandableListAdapter getExpandableListAdapter()
public long getSelectedId()
public long getSelectedPosition()
ExpandableListView.getPackedPositionType(long)
,
ExpandableListView.getPackedPositionGroup(long)
, and
ExpandableListView.getPackedPositionChild(long)
to unpack the returned
packed position.public boolean setSelectedChild(int groupPosition, int childPosition, boolean shouldExpandGroup)
groupPosition
- The position of the group that contains the child.childPosition
- The position of the child within the group.shouldExpandGroup
- Whether the child's group should be expanded if
it is collapsed.public void setSelectedGroup(int groupPosition)
groupPosition
- The position of the group that should be selected.