ListView


public class ListView
extends AbsListView

java.lang.Object
   ↳ android.view.View
     ↳ android.view.ViewGroup
       ↳ android.widget.AdapterView<android.widget.ListAdapter>
         ↳ android.widget.AbsListView
           ↳ android.widget.ListView


Displays a vertically-scrollable collection of views, where each view is positioned immediatelybelow the previous view in the list. For a more modern, flexible, and performant approach to displaying lists, use RecyclerView.

To display a list, you can include a list view in your layout XML file:

<ListView
      android:id="@+id/list_view"
      android:layout_width="match_parent"
      android:layout_height="match_parent" />

A list view is an adapter view that does not know the details, such as type and contents, of the views it contains. Instead list view requests views on demand from a ListAdapter as needed, such as to display new views as the user scrolls up or down.

In order to display items in the list, call setAdapter(android.widget.ListAdapter) to associate an adapter with the list. For a simple example, see the discussion of filling an adapter view with text in the Layouts guide.

To display a more custom view for each item in your dataset, implement a ListAdapter. For example, extend BaseAdapter and create and configure the view for each data item in getView(...):

private class MyAdapter extends BaseAdapter {

      // override other abstract methods here

      @Override
      public View getView(int position, View convertView, ViewGroup container) {
          if (convertView == null) {
              convertView = getLayoutInflater().inflate(R.layout.list_item, container, false);
          }

          ((TextView) convertView.findViewById(android.R.id.text1))
                  .setText(getItem(position));
          return convertView;
      }
  }

ListView attempts to reuse view objects in order to improve performance and avoid a lag in response to user scrolls. To take advantage of this feature, check if the convertView provided to getView(...) is null before creating or inflating a new view object.

To specify an action when a user clicks or taps on a single list item, see Handling click events.

To learn how to populate a list view with a CursorAdapter, see the discussion of filling an adapter view with text in the Layouts guide. See Using a Loader to learn how to avoid blocking the main thread when using a cursor.

Note, many examples use ListActivity or ListFragment to display a list view. Instead, favor the more flexible approach when writing your own app: use a more generic Activity subclass or Fragment subclass and add a list view to the layout or view hierarchy directly. This approach gives you more direct control of the list view and adapter.

Summary

Nested classes

class ListView.FixedViewInfo

A class that represents a fixed view in a list, for example a header at the top or a footer at the bottom. 

XML attributes

android:divider Drawable or color to draw between list items. 
android:dividerHeight Height of the divider. 
android:entries Reference to an array resource that will populate the ListView. 
android:footerDividersEnabled When set to false, the ListView will not draw the divider before each footer view. 
android:headerDividersEnabled When set to false, the ListView will not draw the divider after each header view. 

Inherited XML attributes

Inherited constants

Inherited fields

Public constructors

ListView(Context context)
ListView(Context context, AttributeSet attrs)
ListView(Context context, AttributeSet attrs, int defStyleAttr)
ListView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)

Public methods

void addFooterView(View v, Object data, boolean isSelectable)

Add a fixed view to appear at the bottom of the list.

void addFooterView(View v)

Add a fixed view to appear at the bottom of the list.

void addHeaderView(View v, Object data, boolean isSelectable)

Add a fixed view to appear at the top of the list.

void addHeaderView(View v)

Add a fixed view to appear at the top of the list.

boolean areFooterDividersEnabled()
boolean areHeaderDividersEnabled()
boolean dispatchKeyEvent(KeyEvent event)

Dispatch a key event to the next view on the focus path.

CharSequence getAccessibilityClassName()

A TYPE_VIEW_SCROLLED event should be sent whenever a scroll happens, even if the mFirstPosition and the child count have not changed.

ListAdapter getAdapter()

Returns the adapter currently in use in this ListView.

long[] getCheckItemIds()

This method was deprecated in API level 15. Use AbsListView.getCheckedItemIds() instead.

Drawable getDivider()

Returns the drawable that will be drawn between each item in the list.

int getDividerHeight()
int getFooterViewsCount()
int getHeaderViewsCount()
boolean getItemsCanFocus()
int getMaxScrollAmount()
Drawable getOverscrollFooter()
Drawable getOverscrollHeader()
boolean isOpaque()

Indicates whether this View is opaque.

void onInitializeAccessibilityNodeInfoForItem(View view, int position, AccessibilityNodeInfo info)

Initializes an AccessibilityNodeInfo with information about a particular item in the list.

boolean onKeyDown(int keyCode, KeyEvent event)

Default implementation of KeyEvent.Callback.onKeyDown(): perform press of the view when KeyEvent#KEYCODE_DPAD_CENTER or KeyEvent#KEYCODE_ENTER is released, if the view is enabled and clickable.

boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event)

Default implementation of KeyEvent.Callback.onKeyMultiple(): always returns false (doesn't handle the event).

boolean onKeyUp(int keyCode, KeyEvent event)

Default implementation of KeyEvent.Callback.onKeyUp(): perform clicking of the view when KeyEvent#KEYCODE_DPAD_CENTER, KeyEvent#KEYCODE_ENTER or KeyEvent#KEYCODE_SPACE is released.

boolean removeFooterView(View v)

Removes a previously-added footer view.

boolean removeHeaderView(View v)

Removes a previously-added header view.

boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate)

Called when a child of this group wants a particular rectangle to be positioned onto the screen.

void setAdapter(ListAdapter adapter)

Sets the data behind this ListView.

void setCacheColorHint(int color)

When set to a non-zero value, the cache color hint indicates that this list is always drawn on top of a solid, single-color, opaque background.

void setDivider(Drawable divider)

Sets the drawable that will be drawn between each item in the list.

void setDividerHeight(int height)

Sets the height of the divider that will be drawn between each item in the list.

void setFooterDividersEnabled(boolean footerDividersEnabled)

Enables or disables the drawing of the divider for footer views.

void setHeaderDividersEnabled(boolean headerDividersEnabled)

Enables or disables the drawing of the divider for header views.

void setItemsCanFocus(boolean itemsCanFocus)

Indicates that the views created by the ListAdapter can contain focusable items.

void setOverscrollFooter(Drawable footer)

Sets the drawable that will be drawn below all other list content.

void setOverscrollHeader(Drawable header)

Sets the drawable that will be drawn above all other list content.

void setRemoteViewsAdapter(Intent intent)

Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService through the specified intent.

void setSelection(int position)

Sets the currently selected item.

void setSelectionAfterHeaderView()

setSelectionAfterHeaderView set the selection to be the first list item after the header views.

void smoothScrollByOffset(int offset)

Smoothly scroll to the specified adapter position offset.

void smoothScrollToPosition(int position)

Smoothly scroll to the specified adapter position.

Protected methods

boolean canAnimate()

Indicates whether the view group has the ability to animate its children after the first layout.

void dispatchDraw(Canvas canvas)

Called by draw to draw the child views.

boolean drawChild(Canvas canvas, View child, long drawingTime)

Draw one child of this View Group.

void layoutChildren()

Subclasses must override this method to layout their children.

void onDetachedFromWindow()

This is called when the view is detached from a window.

void onFinishInflate()

Finalize inflating a view from XML.

void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect)

Called by the view system when the focus state of this view changes.

void onMeasure(int widthMeasureSpec, int heightMeasureSpec)

Measure the view and its content to determine the measured width and the measured height.

void onSizeChanged(int w, int h, int oldw, int oldh)

This is called during layout when the size of this view has changed.

Inherited methods

XML attributes

android:divider

Drawable or color to draw between list items.

May be a reference to another resource, in the form "@[+][package:]type/name" or a theme attribute in the form "?[package:]type/name".

May be a color value, in the form of "#rgb", "#argb", "#rrggbb", or "#aarrggbb".

Related methods:

android:dividerHeight

Height of the divider. Will use the intrinsic height of the divider if this is not specified.

May be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), and mm (millimeters).

android:entries

Reference to an array resource that will populate the ListView. For static content, this is simpler than populating the ListView programmatically.

May be a reference to another resource, in the form "@[+][package:]type/name" or a theme attribute in the form "?[package:]type/name".

android:footerDividersEnabled

When set to false, the ListView will not draw the divider before each footer view. The default value is true.

May be a boolean value, such as "true" or "false".

android:headerDividersEnabled

When set to false, the ListView will not draw the divider after each header view. The default value is true.

May be a boolean value, such as "true" or "false".

Public constructors

ListView

Added in API level 1
public ListView (Context context)

Parameters
context Context

ListView

Added in API level 1
public ListView (Context context, 
                AttributeSet attrs)

Parameters
context Context

attrs AttributeSet

ListView

Added in API level 1
public ListView (Context context, 
                AttributeSet attrs, 
                int defStyleAttr)

Parameters
context Context

attrs AttributeSet

defStyleAttr int

ListView

Added in API level 21
public ListView (Context context, 
                AttributeSet attrs, 
                int defStyleAttr, 
                int defStyleRes)

Parameters
context Context

attrs AttributeSet

defStyleAttr int

defStyleRes int

Public methods

addFooterView

Added in API level 1
public void addFooterView (View v, 
                Object data, 
                boolean isSelectable)

Add a fixed view to appear at the bottom of the list. If addFooterView is called more than once, the views will appear in the order they were added. Views added using this call can take focus if they want.

Note: When first introduced, this method could only be called before setting the adapter with setAdapter(android.widget.ListAdapter). Starting with Build.VERSION_CODES.KITKAT, this method may be called at any time. If the ListView's adapter does not extend HeaderViewListAdapter, it will be wrapped with a supporting instance of WrapperListAdapter.

Parameters
v View: The view to add.

data Object: Data to associate with this view

isSelectable boolean: true if the footer view can be selected

addFooterView

Added in API level 1
public void addFooterView (View v)

Add a fixed view to appear at the bottom of the list. If addFooterView is called more than once, the views will appear in the order they were added. Views added using this call can take focus if they want.

Note: When first introduced, this method could only be called before setting the adapter with setAdapter(android.widget.ListAdapter). Starting with Build.VERSION_CODES.KITKAT, this method may be called at any time. If the ListView's adapter does not extend HeaderViewListAdapter, it will be wrapped with a supporting instance of WrapperListAdapter.

Parameters
v View: The view to add.

addHeaderView

Added in API level 1
public void addHeaderView (View v, 
                Object data, 
                boolean isSelectable)

Add a fixed view to appear at the top of the list. If this method is called more than once, the views will appear in the order they were added. Views added using this call can take focus if they want.

Note: When first introduced, this method could only be called before setting the adapter with setAdapter(android.widget.ListAdapter). Starting with Build.VERSION_CODES.KITKAT, this method may be called at any time. If the ListView's adapter does not extend HeaderViewListAdapter, it will be wrapped with a supporting instance of WrapperListAdapter.

Parameters
v View: The view to add.

data Object: Data to associate with this view

isSelectable boolean: whether the item is selectable

addHeaderView

Added in API level 1
public void addHeaderView (View v)

Add a fixed view to appear at the top of the list. If addHeaderView is called more than once, the views will appear in the order they were added. Views added using this call can take focus if they want.

Note: When first introduced, this method could only be called before setting the adapter with setAdapter(android.widget.ListAdapter). Starting with Build.VERSION_CODES.KITKAT, this method may be called at any time. If the ListView's adapter does not extend HeaderViewListAdapter, it will be wrapped with a supporting instance of WrapperListAdapter.

Parameters
v View: The view to add.

areFooterDividersEnabled

Added in API level 19
public boolean areFooterDividersEnabled ()

Returns
boolean Whether the drawing of the divider for footer views is enabled

areHeaderDividersEnabled

Added in API level 19
public boolean areHeaderDividersEnabled ()

Returns
boolean Whether the drawing of the divider for header views is enabled

dispatchKeyEvent

Added in API level 1
public boolean dispatchKeyEvent (KeyEvent event)

Dispatch a key event to the next view on the focus path. This path runs from the top of the view tree down to the currently focused view. If this view has focus, it will dispatch to itself. Otherwise it will dispatch the next node down the focus path. This method also fires any key listeners.

Parameters
event KeyEvent: The key event to be dispatched.

Returns
boolean True if the event was handled, false otherwise.

getAccessibilityClassName

Added in API level 23
public CharSequence getAccessibilityClassName ()

A TYPE_VIEW_SCROLLED event should be sent whenever a scroll happens, even if the mFirstPosition and the child count have not changed.

Returns
CharSequence

getAdapter

Added in API level 1
public ListAdapter getAdapter ()

Returns the adapter currently in use in this ListView. The returned adapter might not be the same adapter passed to setAdapter(android.widget.ListAdapter) but might be a WrapperListAdapter.

Returns
ListAdapter The adapter currently used to display data in this ListView.

getCheckItemIds

Added in API level 4
Deprecated in API level 15
public long[] getCheckItemIds ()

This method was deprecated in API level 15.
Use AbsListView.getCheckedItemIds() instead.

Returns the set of checked items ids. The result is only valid if the choice mode has not been set to AbsListView.CHOICE_MODE_NONE.

Returns
long[] A new array which contains the id of each checked item in the list.

getDivider

Added in API level 1
public Drawable getDivider ()

Returns the drawable that will be drawn between each item in the list.

Related XML Attributes:

Returns
Drawable the current drawable drawn between list elements This value may be null.

getDividerHeight

Added in API level 1
public int getDividerHeight ()

Returns
int Returns the height of the divider that will be drawn between each item in the list.

getFooterViewsCount

Added in API level 1
public int getFooterViewsCount ()

Returns
int

getHeaderViewsCount

Added in API level 1
public int getHeaderViewsCount ()

Returns
int

getItemsCanFocus

Added in API level 1
public boolean getItemsCanFocus ()

Returns
boolean Whether the views created by the ListAdapter can contain focusable items.

getMaxScrollAmount

Added in API level 1
public int getMaxScrollAmount ()

Returns
int The maximum amount a list view will scroll in response to an arrow event.

getOverscrollFooter

Added in API level 9
public Drawable getOverscrollFooter ()

Returns
Drawable The drawable that will be drawn below all other list content

getOverscrollHeader

Added in API level 9
public Drawable getOverscrollHeader ()

Returns
Drawable The drawable that will be drawn above all other list content

isOpaque

Added in API level 7
public boolean isOpaque ()

Indicates whether this View is opaque. An opaque View guarantees that it will draw all the pixels overlapping its bounds using a fully opaque color. Subclasses of View should override this method whenever possible to indicate whether an instance is opaque. Opaque Views are treated in a special way by the View hierarchy, possibly allowing it to perform optimizations during invalidate/draw passes.

Returns
boolean True if this View is guaranteed to be fully opaque, false otherwise.

onInitializeAccessibilityNodeInfoForItem

Added in API level 19
public void onInitializeAccessibilityNodeInfoForItem (View view, 
                int position, 
                AccessibilityNodeInfo info)

Initializes an AccessibilityNodeInfo with information about a particular item in the list.

Parameters
view View: View representing the list item.

position int: Position of the list item within the adapter.

info AccessibilityNodeInfo: Node info to populate.

onKeyDown

Added in API level 1
public boolean onKeyDown (int keyCode, 
                KeyEvent event)

Default implementation of KeyEvent.Callback.onKeyDown(): perform press of the view when KeyEvent#KEYCODE_DPAD_CENTER or KeyEvent#KEYCODE_ENTER is released, if the view is enabled and clickable.

Key presses in software keyboards will generally NOT trigger this listener, although some may elect to do so in some situations. Do not rely on this to catch software key presses.

Parameters
keyCode int: a key code that represents the button pressed, from KeyEvent

event KeyEvent: the KeyEvent object that defines the button action

Returns
boolean If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

onKeyMultiple

Added in API level 1
public boolean onKeyMultiple (int keyCode, 
                int repeatCount, 
                KeyEvent event)

Default implementation of KeyEvent.Callback.onKeyMultiple(): always returns false (doesn't handle the event).

Key presses in software keyboards will generally NOT trigger this listener, although some may elect to do so in some situations. Do not rely on this to catch software key presses.

Parameters
keyCode int: A key code that represents the button pressed, from KeyEvent.

repeatCount int: The number of times the action was made.

event KeyEvent: The KeyEvent object that defines the button action.

Returns
boolean If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

onKeyUp

Added in API level 1
public boolean onKeyUp (int keyCode, 
                KeyEvent event)

Default implementation of KeyEvent.Callback.onKeyUp(): perform clicking of the view when KeyEvent#KEYCODE_DPAD_CENTER, KeyEvent#KEYCODE_ENTER or KeyEvent#KEYCODE_SPACE is released.

Key presses in software keyboards will generally NOT trigger this listener, although some may elect to do so in some situations. Do not rely on this to catch software key presses.

Parameters
keyCode int: A key code that represents the button pressed, from KeyEvent.

event KeyEvent: The KeyEvent object that defines the button action.

Returns
boolean If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

removeFooterView

Added in API level 1
public boolean removeFooterView (View v)

Removes a previously-added footer view.

Parameters
v View: The view to remove

Returns
boolean true if the view was removed, false if the view was not a footer view

removeHeaderView

Added in API level 1
public boolean removeHeaderView (View v)

Removes a previously-added header view.

Parameters
v View: The view to remove

Returns
boolean true if the view was removed, false if the view was not a header view

requestChildRectangleOnScreen

Added in API level 1
public boolean requestChildRectangleOnScreen (View child, 
                Rect rect, 
                boolean immediate)

Called when a child of this group wants a particular rectangle to be positioned onto the screen. ViewGroups overriding this can trust that:

  • child will be a direct child of this group
  • rectangle will be in the child's content coordinates

ViewGroups overriding this should uphold the contract:

  • nothing will change if the rectangle is already visible
  • the view port will be scrolled only just enough to make the rectangle visible
    • Parameters
      child View: The direct child making the request. This value cannot be null.

      rect Rect: The rectangle in the child's coordinates the child wishes to be on the screen.

      immediate boolean: True to forbid animated or delayed scrolling, false otherwise

      Returns
      boolean Whether the group scrolled to handle the operation

setAdapter

Added in API level 1
public void setAdapter (ListAdapter adapter)

Sets the data behind this ListView. The adapter passed to this method may be wrapped by a WrapperListAdapter, depending on the ListView features currently in use. For instance, adding headers and/or footers will cause the adapter to be wrapped.

Parameters
adapter ListAdapter: The ListAdapter which is responsible for maintaining the data backing this list and for producing a view to represent an item in that data set.

See also:

setCacheColorHint

Added in API level 1
public void setCacheColorHint (int color)

When set to a non-zero value, the cache color hint indicates that this list is always drawn on top of a solid, single-color, opaque background. Zero means that what's behind this object is translucent (non solid) or is not made of a single color. This hint will not affect any existing background drawable set on this view ( typically set via View.setBackgroundDrawable(android.graphics.drawable.Drawable)).

Parameters
color int: The background color

setDivider

Added in API level 1
public void setDivider (Drawable divider)

Sets the drawable that will be drawn between each item in the list.

Note: If the drawable does not have an intrinsic height, you should also call setDividerHeight(int).

Related XML Attributes:

Parameters
divider Drawable: the drawable to use This value may be null.

setDividerHeight

Added in API level 1
public void setDividerHeight (int height)

Sets the height of the divider that will be drawn between each item in the list. Calling this will override the intrinsic height as set by setDivider(android.graphics.drawable.Drawable)

Parameters
height int: The new height of the divider in pixels.

setFooterDividersEnabled

Added in API level 3
public void setFooterDividersEnabled (boolean footerDividersEnabled)

Enables or disables the drawing of the divider for footer views.

Parameters
footerDividersEnabled boolean: True to draw the footers, false otherwise.

setHeaderDividersEnabled

Added in API level 3
public void setHeaderDividersEnabled (boolean headerDividersEnabled)

Enables or disables the drawing of the divider for header views.

Parameters
headerDividersEnabled boolean: True to draw the headers, false otherwise.

setItemsCanFocus

Added in API level 1
public void setItemsCanFocus (boolean itemsCanFocus)

Indicates that the views created by the ListAdapter can contain focusable items.

Parameters
itemsCanFocus boolean: true if items can get focus, false otherwise

setOverscrollFooter

Added in API level 9
public void setOverscrollFooter (Drawable footer)

Sets the drawable that will be drawn below all other list content. This area can become visible when the user overscrolls the list, or when the list's content does not fully fill the container area.

Parameters
footer Drawable: The drawable to use

setOverscrollHeader

Added in API level 9
public void setOverscrollHeader (Drawable header)

Sets the drawable that will be drawn above all other list content. This area can become visible when the user overscrolls the list.

Parameters
header Drawable: The drawable to use

setRemoteViewsAdapter

Added in API level 11
public void setRemoteViewsAdapter (Intent intent)

Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService through the specified intent.

Parameters
intent Intent: the intent used to identify the RemoteViewsService for the adapter to connect to.

setSelection

Added in API level 1
public void setSelection (int position)

Sets the currently selected item. If in touch mode, the item will not be selected but it will still be positioned appropriately. If the specified selection position is less than 0, then the item at position 0 will be selected.

Parameters
position int: Index (starting at 0) of the data item to be selected.

setSelectionAfterHeaderView

Added in API level 1
public void setSelectionAfterHeaderView ()

setSelectionAfterHeaderView set the selection to be the first list item after the header views.

smoothScrollByOffset

Added in API level 11
public void smoothScrollByOffset (int offset)

Smoothly scroll to the specified adapter position offset. The view will scroll such that the indicated position is displayed.

Parameters
offset int: The amount to offset from the adapter position to scroll to.

smoothScrollToPosition

Added in API level 8
public void smoothScrollToPosition (int position)

Smoothly scroll to the specified adapter position. The view will scroll such that the indicated position is displayed.

Parameters
position int: Scroll to this adapter position.

Protected methods

canAnimate

Added in API level 1
protected boolean canAnimate ()

Indicates whether the view group has the ability to animate its children after the first layout.

Returns
boolean true if the children can be animated, false otherwise

dispatchDraw

Added in API level 1
protected void dispatchDraw (Canvas canvas)

Called by draw to draw the child views. This may be overridden by derived classes to gain control just before its children are drawn (but after its own view has been drawn).

Parameters
canvas Canvas: This value cannot be null.

drawChild

Added in API level 1
protected boolean drawChild (Canvas canvas, 
                View child, 
                long drawingTime)

Draw one child of this View Group. This method is responsible for getting the canvas in the right state. This includes clipping, translating so that the child's scrolled origin is at 0, 0, and applying any animation transformations.

Parameters
canvas Canvas: The canvas on which to draw the child This value cannot be null.

child View: Who to draw

drawingTime long: The time at which draw is occurring

Returns
boolean True if an invalidate() was issued

layoutChildren

Added in API level 1
protected void layoutChildren ()

Subclasses must override this method to layout their children.

onDetachedFromWindow

Added in API level 1
protected void onDetachedFromWindow ()

This is called when the view is detached from a window. At this point it no longer has a surface for drawing.
If you override this method you must call through to the superclass implementation.

onFinishInflate

Added in API level 1
protected void onFinishInflate ()

Finalize inflating a view from XML. This is called as the last phase of inflation, after all child views have been added.

Even if the subclass overrides onFinishInflate, they should always be sure to call the super method, so that we get called.
If you override this method you must call through to the superclass implementation.

onFocusChanged

Added in API level 1
protected void onFocusChanged (boolean gainFocus, 
                int direction, 
                Rect previouslyFocusedRect)

Called by the view system when the focus state of this view changes. When the focus change event is caused by directional navigation, direction and previouslyFocusedRect provide insight into where the focus is coming from. When overriding, be sure to call up through to the super class so that the standard focus handling will occur.
If you override this method you must call through to the superclass implementation.

Parameters
gainFocus boolean: True if the View has focus; false otherwise.

direction int: The direction focus has moved when requestFocus() is called to give this view focus. Values are View.FOCUS_UP, View.FOCUS_DOWN, View.FOCUS_LEFT, View.FOCUS_RIGHT, View.FOCUS_FORWARD, or View.FOCUS_BACKWARD. It may not always apply, in which case use the default. Value is View.FOCUS_BACKWARD, View.FOCUS_FORWARD, View.FOCUS_LEFT, View.FOCUS_UP, View.FOCUS_RIGHT, or View.FOCUS_DOWN

previouslyFocusedRect Rect: The rectangle, in this view's coordinate system, of the previously focused view. If applicable, this will be passed in as finer grained information about where the focus is coming from (in addition to direction). Will be null otherwise.

onMeasure

Added in API level 1
protected void onMeasure (int widthMeasureSpec, 
                int heightMeasureSpec)

Measure the view and its content to determine the measured width and the measured height. This method is invoked by measure(int, int) and should be overridden by subclasses to provide accurate and efficient measurement of their contents.

CONTRACT: When overriding this method, you must call setMeasuredDimension(int, int) to store the measured width and height of this view. Failure to do so will trigger an IllegalStateException, thrown by measure(int, int). Calling the superclass' onMeasure(int, int) is a valid use.

The base class implementation of measure defaults to the background size, unless a larger size is allowed by the MeasureSpec. Subclasses should override onMeasure(int, int) to provide better measurements of their content.

If this method is overridden, it is the subclass's responsibility to make sure the measured height and width are at least the view's minimum height and width (getSuggestedMinimumHeight() and getSuggestedMinimumWidth()).

Parameters
widthMeasureSpec int: horizontal space requirements as imposed by the parent. The requirements are encoded with View.MeasureSpec.

heightMeasureSpec int: vertical space requirements as imposed by the parent. The requirements are encoded with View.MeasureSpec.

onSizeChanged

Added in API level 1
protected void onSizeChanged (int w, 
                int h, 
                int oldw, 
                int oldh)

This is called during layout when the size of this view has changed. If you were just added to the view hierarchy, you're called with the old values of 0.

Parameters
w int: Current width of this view.

h int: Current height of this view.

oldw int: Old width of this view.

oldh int: Old height of this view.