Skip to content

Most visited

Recently visited

navigation
Added in API level 1

ListActivity

public class ListActivity
extends Activity

java.lang.Object
   ↳ android.content.Context
     ↳ android.content.ContextWrapper
       ↳ android.view.ContextThemeWrapper
         ↳ android.app.Activity
           ↳ android.app.ListActivity
Known Direct Subclasses


An activity that displays a list of items by binding to a data source such as an array or Cursor, and exposes event handlers when the user selects an item.

ListActivity hosts a ListView object that can be bound to different data sources, typically either an array or a Cursor holding query results. Binding, screen layout, and row layout are discussed in the following sections.

Screen Layout

ListActivity has a default layout that consists of a single, full-screen list in the center of the screen. 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 a ListView object with the id "@android:id/list" (or 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:id/empty". Note that when an empty view is present, the 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">

     <ListView android:id="@android:id/list"
               android:layout_width="match_parent"
               android:layout_height="match_parent"
               android:background="#00FF00"
               android:layout_weight="1"
               android:drawSelectorOnTop="false"/>

     <TextView android:id="@android:id/empty"
               android:layout_width="match_parent"
               android:layout_height="match_parent"
               android:background="#FF0000"
               android:text="No data"/>
 </LinearLayout>
 

Row Layout

You can specify the layout of individual rows in the list. You do this by specifying a layout resource in the ListAdapter object hosted by the activity (the ListAdapter binds the ListView to the data; more on this later).

A ListAdapter constructor takes a parameter that specifies a layout resource for each row. It also has two additional parameters that let you specify which data field to associate with which object in the row layout resource. These two parameters are typically parallel arrays.

Android provides some standard row layout resources. These are in the 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 ListActivity's ListView object to data using a class that implements the ListAdapter interface. Android provides two standard list adapters: SimpleAdapter for static data (Maps), and SimpleCursorAdapter for Cursor query results.

The following code from a custom ListActivity demonstrates querying the Contacts provider for all contacts, then binding the Name and Company fields to a two line row layout in the activity's ListView.

 public class MyListAdapter extends ListActivity {

     @Override
     protected void onCreate(Bundle savedInstanceState){
         super.onCreate(savedInstanceState);

         // We'll define a custom screen layout here (the one shown above), but
         // typically, you could just use the standard ListActivity layout.
         setContentView(R.layout.custom_list_activity_view);

         // Query for all people contacts using the Contacts.People convenience class.
         // Put a managed wrapper around the retrieved cursor so we don't have to worry about
         // requerying or closing it as the activity changes state.
         mCursor = this.getContentResolver().query(People.CONTENT_URI, null, null, null, null);
         startManagingCursor(mCursor);

         // Now create a new list adapter bound to the cursor.
         // SimpleListAdapter is designed for binding to a Cursor.
         ListAdapter adapter = new SimpleCursorAdapter(
                 this, // Context.
                 android.R.layout.two_line_list_item,  // Specify the row template to use (here, two columns bound to the two retrieved cursor
 rows).
                 mCursor,                                              // Pass in the cursor to bind to.
                 new String[] {People.NAME, People.COMPANY},           // Array of cursor columns to bind to.
                 new int[] {android.R.id.text1, android.R.id.text2});  // Parallel array of which template objects to bind to those columns.

         // Bind to our new adapter.
         setListAdapter(adapter);
     }
 }
 

See also:

Summary

Inherited constants

From class android.app.Activity
From class android.content.Context
From interface android.content.ComponentCallbacks2

Inherited fields

From class android.app.Activity

Public constructors

ListActivity()

Public methods

ListAdapter getListAdapter()

Get the ListAdapter associated with this activity's ListView.

ListView getListView()

Get the activity's list view widget.

long getSelectedItemId()

Get the cursor row ID of the currently selected list item.

int getSelectedItemPosition()

Get the position of the currently selected list item.

void onContentChanged()

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

void setListAdapter(ListAdapter adapter)

Provide the cursor for the list view.

void setSelection(int position)

Set the currently selected list item to the specified position with the adapter's data

Protected methods

void onDestroy()

Perform any final cleanup before an activity is destroyed.

void onListItemClick(ListView l, View v, int position, long id)

This method will be called when an item in the list is selected.

void onRestoreInstanceState(Bundle state)

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

Inherited methods

From class android.app.Activity
From class android.view.ContextThemeWrapper
From class android.content.ContextWrapper
From class android.content.Context
From class java.lang.Object
From interface android.view.LayoutInflater.Factory2
From interface android.view.Window.Callback
From interface android.view.KeyEvent.Callback
From interface android.view.View.OnCreateContextMenuListener
From interface android.content.ComponentCallbacks2
From interface android.view.LayoutInflater.Factory
From interface android.content.ComponentCallbacks

Public constructors

ListActivity

Added in API level 1
ListActivity ()

Public methods

getListAdapter

Added in API level 1
ListAdapter getListAdapter ()

Get the ListAdapter associated with this activity's ListView.

Returns
ListAdapter

getListView

Added in API level 1
ListView getListView ()

Get the activity's list view widget.

Returns
ListView

getSelectedItemId

Added in API level 1
long getSelectedItemId ()

Get the cursor row ID of the currently selected list item.

Returns
long

getSelectedItemPosition

Added in API level 1
int getSelectedItemPosition ()

Get the position of the currently selected list item.

Returns
int

onContentChanged

Added in API level 1
void onContentChanged ()

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

See also:

setListAdapter

Added in API level 1
void setListAdapter (ListAdapter adapter)

Provide the cursor for the list view.

Parameters
adapter ListAdapter

setSelection

Added in API level 1
void setSelection (int position)

Set the currently selected list item to the specified position with the adapter's data

Protected methods

onDestroy

Added in API level 1
void onDestroy ()

Perform any final cleanup before an activity is destroyed. This can happen either because the activity is finishing (someone called finish() on it, or because the system is temporarily destroying this instance of the activity to save space. You can distinguish between these two scenarios with the isFinishing() method.

Note: do not count on this method being called as a place for saving data! For example, if an activity is editing data in a content provider, those edits should be committed in either onPause() or onSaveInstanceState(Bundle), not here. This method is usually implemented to free resources like threads that are associated with an activity, so that a destroyed activity does not leave such things around while the rest of its application is still running. There are situations where the system will simply kill the activity's hosting process without calling this method (or any others) in it, so it should not be used to do things that are intended to remain around after the process goes away.

Derived classes must call through to the super class's implementation of this method. If they do not, an exception will be thrown.

See also:

onListItemClick

Added in API level 1
void onListItemClick (ListView l, 
                View v, 
                int position, 
                long id)

This method will be called when an item in the list is selected. Subclasses should override. Subclasses can call getListView().getItemAtPosition(position) if they need to access the data associated with the selected item.

Parameters
l ListView: The ListView where the click happened
v View: The view that was clicked within the ListView
position int: The position of the view in the list
id long: The row id of the item that was clicked

onRestoreInstanceState

Added in API level 1
void onRestoreInstanceState (Bundle state)

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

Parameters
state Bundle: the data most recently supplied in onSaveInstanceState(Bundle).

See also:

This site uses cookies to store your preferences for site-specific language and display options.

Hooray!

This class requires API level or higher

This doc is hidden because your selected API level for the documentation is . You can change the documentation API level with the selector above the left navigation.

For more information about specifying the API level your app requires, read Supporting Different Platform Versions.