Android APIs
public class

Gallery

extends AbsSpinner
implements GestureDetector.OnGestureListener
java.lang.Object
   ↳ android.view.View
     ↳ android.view.ViewGroup
       ↳ android.widget.AdapterView<T extends android.widget.Adapter>
         ↳ android.widget.AbsSpinner
           ↳ android.widget.Gallery

This class was deprecated in API level 16.
This widget is no longer supported. Other horizontally scrolling widgets include HorizontalScrollView and ViewPager from the support library.

Class Overview

A view that shows items in a center-locked, horizontally scrolling list.

The default values for the Gallery assume you will be using Theme_galleryItemBackground as the background for each View given to the Gallery from the Adapter. If you are not doing this, you may need to adjust some Gallery properties, such as the spacing.

Views given to the Gallery should use Gallery.LayoutParams as their layout parameters type.

Summary

Nested Classes
class Gallery.LayoutParams Gallery extends LayoutParams to provide a place to hold current Transformation information along with previous position/transformation info. 
XML Attributes
Attribute Name Related Method Description
android:animationDuration setAnimationDuration(int) Sets how long a transition animation should run (in milliseconds) when layout has changed. 
android:gravity setGravity(int) Specifies how an object should position its content, on both the X and Y axes, within its own bounds. 
android:spacing setSpacing(int)  
android:unselectedAlpha setUnselectedAlpha(float) Sets the alpha on the items that are not selected. 
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Inherited XML Attributes
From class android.widget.AbsSpinner
From class android.view.ViewGroup
From class android.view.View
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Inherited Constants
From class android.widget.AdapterView
From class android.view.ViewGroup
From class android.view.View
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Inherited Fields
From class android.view.View
Public Constructors
Gallery(Context context)
Gallery(Context context, AttributeSet attrs)
Gallery(Context context, AttributeSet attrs, int defStyle)
Public Methods
boolean dispatchKeyEvent(KeyEvent event)
Dispatch a key event to the next view on the focus path.
void dispatchSetSelected(boolean selected)
Dispatch setSelected to all of this View's children.
ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs)
Returns a new set of layout parameters based on the supplied attributes set.
boolean onDown(MotionEvent e)
Notified when a tap occurs with the down MotionEvent that triggered it.
boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
Notified of a fling event when it occurs with the initial on down MotionEvent and the matching up MotionEvent.
void onInitializeAccessibilityEvent(AccessibilityEvent event)
Initializes an AccessibilityEvent with information about this View which is the event source.
void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info)
Initializes an AccessibilityNodeInfo with information about this view.
boolean onKeyDown(int keyCode, KeyEvent event)
Handles left, right, and clicking
boolean onKeyUp(int keyCode, KeyEvent event)
Default implementation of KeyEvent.Callback.onKeyUp(): perform clicking of the view when KEYCODE_DPAD_CENTER or KEYCODE_ENTER is released.
void onLongPress(MotionEvent e)
Notified when a long press occurs with the initial on down MotionEvent that trigged it.
boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
Notified when a scroll occurs with the initial on down MotionEvent and the current move MotionEvent.
void onShowPress(MotionEvent e)
The user has performed a down MotionEvent and not performed a move or up yet.
boolean onSingleTapUp(MotionEvent e)
Notified when a tap occurs with the up MotionEvent that triggered it.
boolean onTouchEvent(MotionEvent event)
Implement this method to handle touch screen motion events.
boolean performAccessibilityAction(int action, Bundle arguments)
Performs the specified accessibility action on the view.
void setAnimationDuration(int animationDurationMillis)
Sets how long the transition animation should run when a child view changes position.
void setCallbackDuringFling(boolean shouldCallback)
Whether or not to callback on any getOnItemSelectedListener() while the items are being flinged.
void setGravity(int gravity)
Describes how the child views are aligned.
void setSpacing(int spacing)
Sets the spacing between items in a Gallery
void setUnselectedAlpha(float unselectedAlpha)
Sets the alpha of items that are not selected in the Gallery.
boolean showContextMenu()
Bring up the context menu for this view.
boolean showContextMenuForChild(View originalView)
Bring up a context menu for the specified view or its ancestors.
Protected Methods
boolean checkLayoutParams(ViewGroup.LayoutParams p)
int computeHorizontalScrollExtent()

Compute the horizontal extent of the horizontal scrollbar's thumb within the horizontal range.

int computeHorizontalScrollOffset()

Compute the horizontal offset of the horizontal scrollbar's thumb within the horizontal range.

int computeHorizontalScrollRange()

Compute the horizontal range that the horizontal scrollbar represents.

void dispatchSetPressed(boolean pressed)
Dispatch setPressed to all of this View's children.
ViewGroup.LayoutParams generateDefaultLayoutParams()
Returns a set of default layout parameters.
ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p)
Returns a safe set of layout parameters based on the supplied layout params.
int getChildDrawingOrder(int childCount, int i)
Returns the index of the child to draw for this iteration.
boolean getChildStaticTransformation(View child, Transformation t)
Sets t to be the static transformation of the child, if set, returning a boolean to indicate whether a static transform was set.
ContextMenu.ContextMenuInfo getContextMenuInfo()
Views should implement this if they have extra information to associate with the context menu.
void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect)
Called by the view system when the focus state of this view changes.
void onLayout(boolean changed, int l, int t, int r, int b)
Called from layout when this view should assign a size and position to each of its children.
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Inherited Methods
From class android.widget.AbsSpinner
From class android.widget.AdapterView
From class android.view.ViewGroup
From class android.view.View
From class java.lang.Object
From interface android.graphics.drawable.Drawable.Callback
From interface android.view.GestureDetector.OnGestureListener
From interface android.view.KeyEvent.Callback
From interface android.view.ViewManager
From interface android.view.ViewParent
From interface android.view.accessibility.AccessibilityEventSource

XML Attributes

android:animationDuration

Sets how long a transition animation should run (in milliseconds) when layout has changed. Only relevant if animation is turned on.

Must be an integer value, such as "100".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol animationDuration.

Related Methods

android:gravity

Specifies how an object should position its content, on both the X and Y axes, within its own bounds.

Must be one or more (separated by '|') of the following constant values.

ConstantValueDescription
top0x30 Push object to the top of its container, not changing its size.
bottom0x50 Push object to the bottom of its container, not changing its size.
left0x03 Push object to the left of its container, not changing its size.
right0x05 Push object to the right of its container, not changing its size.
center_vertical0x10 Place object in the vertical center of its container, not changing its size.
fill_vertical0x70 Grow the vertical size of the object if needed so it completely fills its container.
center_horizontal0x01 Place object in the horizontal center of its container, not changing its size.
fill_horizontal0x07 Grow the horizontal size of the object if needed so it completely fills its container.
center0x11 Place the object in the center of its container in both the vertical and horizontal axis, not changing its size.
fill0x77 Grow the horizontal and vertical size of the object if needed so it completely fills its container.
clip_vertical0x80 Additional option that can be set to have the top and/or bottom edges of the child clipped to its container's bounds. The clip will be based on the vertical gravity: a top gravity will clip the bottom edge, a bottom gravity will clip the top edge, and neither will clip both edges.
clip_horizontal0x08 Additional option that can be set to have the left and/or right edges of the child clipped to its container's bounds. The clip will be based on the horizontal gravity: a left gravity will clip the right edge, a right gravity will clip the left edge, and neither will clip both edges.
start0x00800003 Push object to the beginning of its container, not changing its size.
end0x00800005 Push object to the end of its container, not changing its size.

This corresponds to the global attribute resource symbol gravity.

Related Methods

android:spacing

Related Methods

android:unselectedAlpha

Sets the alpha on the items that are not selected.

Must be a floating point value, such as "1.2".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol unselectedAlpha.

Related Methods

Public Constructors

public Gallery (Context context)

Added in API level 1

public Gallery (Context context, AttributeSet attrs)

Added in API level 1

public Gallery (Context context, AttributeSet attrs, int defStyle)

Added in API level 1

Public Methods

public boolean dispatchKeyEvent (KeyEvent event)

Added in API level 1

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 The key event to be dispatched.
Returns
  • True if the event was handled, false otherwise.

public void dispatchSetSelected (boolean selected)

Added in API level 1

Dispatch setSelected to all of this View's children.

Parameters
selected The new selected state

public ViewGroup.LayoutParams generateLayoutParams (AttributeSet attrs)

Added in API level 1

Returns a new set of layout parameters based on the supplied attributes set.

Parameters
attrs the attributes to build the layout parameters from
Returns

public boolean onDown (MotionEvent e)

Added in API level 1

Notified when a tap occurs with the down MotionEvent that triggered it. This will be triggered immediately for every down event. All other events should be preceded by this.

Parameters
e The down motion event.

public boolean onFling (MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)

Added in API level 1

Notified of a fling event when it occurs with the initial on down MotionEvent and the matching up MotionEvent. The calculated velocity is supplied along the x and y axis in pixels per second.

Parameters
e1 The first down motion event that started the fling.
e2 The move motion event that triggered the current onFling.
velocityX The velocity of this fling measured in pixels per second along the x axis.
velocityY The velocity of this fling measured in pixels per second along the y axis.
Returns
  • true if the event is consumed, else false

public void onInitializeAccessibilityEvent (AccessibilityEvent event)

Added in API level 14

Initializes an AccessibilityEvent with information about this View which is the event source. In other words, the source of an accessibility event is the view whose state change triggered firing the event.

Example: Setting the password property of an event in addition to properties set by the super implementation:

 public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
     super.onInitializeAccessibilityEvent(event);
     event.setPassword(true);
 }

If an View.AccessibilityDelegate has been specified via calling setAccessibilityDelegate(AccessibilityDelegate) its onInitializeAccessibilityEvent(View, AccessibilityEvent) is responsible for handling this call.

Note: Always call the super implementation before adding information to the event, in case the default implementation has basic information to add.

Parameters
event The event to initialize.

public void onInitializeAccessibilityNodeInfo (AccessibilityNodeInfo info)

Added in API level 14

Initializes an AccessibilityNodeInfo with information about this view. The base implementation sets:

Subclasses should override this method, call the super implementation, and set additional attributes.

If an View.AccessibilityDelegate has been specified via calling setAccessibilityDelegate(AccessibilityDelegate) its onInitializeAccessibilityNodeInfo(View, AccessibilityNodeInfo) is responsible for handling this call.

Parameters
info The instance to initialize.

public boolean onKeyDown (int keyCode, KeyEvent event)

Added in API level 1

Handles left, right, and clicking

Parameters
keyCode A key code that represents the button pressed, from KeyEvent.
event The KeyEvent object that defines the button action.
Returns
  • If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

public boolean onKeyUp (int keyCode, KeyEvent event)

Added in API level 1

Default implementation of KeyEvent.Callback.onKeyUp(): perform clicking of the view when KEYCODE_DPAD_CENTER or KEYCODE_ENTER 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 A key code that represents the button pressed, from KeyEvent.
event The KeyEvent object that defines the button action.
Returns
  • If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

public void onLongPress (MotionEvent e)

Added in API level 1

Notified when a long press occurs with the initial on down MotionEvent that trigged it.

Parameters
e The initial on down motion event that started the longpress.

public boolean onScroll (MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)

Added in API level 1

Notified when a scroll occurs with the initial on down MotionEvent and the current move MotionEvent. The distance in x and y is also supplied for convenience.

Parameters
e1 The first down motion event that started the scrolling.
e2 The move motion event that triggered the current onScroll.
distanceX The distance along the X axis that has been scrolled since the last call to onScroll. This is NOT the distance between e1 and e2.
distanceY The distance along the Y axis that has been scrolled since the last call to onScroll. This is NOT the distance between e1 and e2.
Returns
  • true if the event is consumed, else false

public void onShowPress (MotionEvent e)

Added in API level 1

The user has performed a down MotionEvent and not performed a move or up yet. This event is commonly used to provide visual feedback to the user to let them know that their action has been recognized i.e. highlight an element.

Parameters
e The down motion event

public boolean onSingleTapUp (MotionEvent e)

Added in API level 1

Notified when a tap occurs with the up MotionEvent that triggered it.

Parameters
e The up motion event that completed the first tap
Returns
  • true if the event is consumed, else false

public boolean onTouchEvent (MotionEvent event)

Added in API level 1

Implement this method to handle touch screen motion events.

If this method is used to detect click actions, it is recommended that the actions be performed by implementing and calling performClick(). This will ensure consistent system behavior, including:

  • obeying click sound preferences
  • dispatching OnClickListener calls
  • handling ACTION_CLICK when accessibility features are enabled

Parameters
event The motion event.
Returns
  • True if the event was handled, false otherwise.

public boolean performAccessibilityAction (int action, Bundle arguments)

Added in API level 16

Performs the specified accessibility action on the view. For possible accessibility actions look at AccessibilityNodeInfo.

If an View.AccessibilityDelegate has been specified via calling setAccessibilityDelegate(AccessibilityDelegate) its performAccessibilityAction(View, int, Bundle) is responsible for handling this call.

Parameters
action The action to perform.
arguments Optional action arguments.
Returns
  • Whether the action was performed.

public void setAnimationDuration (int animationDurationMillis)

Added in API level 1

Sets how long the transition animation should run when a child view changes position. Only relevant if animation is turned on.

Related XML Attributes
Parameters
animationDurationMillis The duration of the transition, in milliseconds.

public void setCallbackDuringFling (boolean shouldCallback)

Added in API level 1

Whether or not to callback on any getOnItemSelectedListener() while the items are being flinged. If false, only the final selected item will cause the callback. If true, all items between the first and the final will cause callbacks.

Parameters
shouldCallback Whether or not to callback on the listener while the items are being flinged.

public void setGravity (int gravity)

Added in API level 1

Describes how the child views are aligned.

Related XML Attributes

public void setSpacing (int spacing)

Added in API level 1

Sets the spacing between items in a Gallery

Related XML Attributes
Parameters
spacing The spacing in pixels between items in the Gallery

public void setUnselectedAlpha (float unselectedAlpha)

Added in API level 1

Sets the alpha of items that are not selected in the Gallery.

Related XML Attributes
Parameters
unselectedAlpha the alpha for the items that are not selected.

public boolean showContextMenu ()

Added in API level 1

Bring up the context menu for this view.

Returns
  • Whether a context menu was displayed.

public boolean showContextMenuForChild (View originalView)

Added in API level 1

Bring up a context menu for the specified view or its ancestors.

In most cases, a subclass does not need to override this. However, if the subclass is added directly to the window manager (for example, addView(View, android.view.ViewGroup.LayoutParams)) then it should override this and show the context menu.

Parameters
originalView The source view where the context menu was first invoked
Returns
  • true if a context menu was displayed

Protected Methods

protected boolean checkLayoutParams (ViewGroup.LayoutParams p)

Added in API level 1

protected int computeHorizontalScrollExtent ()

Added in API level 1

Compute the horizontal extent of the horizontal scrollbar's thumb within the horizontal range. This value is used to compute the length of the thumb within the scrollbar's track.

The range is expressed in arbitrary units that must be the same as the units used by computeHorizontalScrollRange() and computeHorizontalScrollOffset().

The default extent is the drawing width of this view.

Returns
  • the horizontal extent of the scrollbar's thumb

protected int computeHorizontalScrollOffset ()

Added in API level 1

Compute the horizontal offset of the horizontal scrollbar's thumb within the horizontal range. This value is used to compute the position of the thumb within the scrollbar's track.

The range is expressed in arbitrary units that must be the same as the units used by computeHorizontalScrollRange() and computeHorizontalScrollExtent().

The default offset is the scroll offset of this view.

Returns
  • the horizontal offset of the scrollbar's thumb

protected int computeHorizontalScrollRange ()

Added in API level 1

Compute the horizontal range that the horizontal scrollbar represents.

The range is expressed in arbitrary units that must be the same as the units used by computeHorizontalScrollExtent() and computeHorizontalScrollOffset().

The default range is the drawing width of this view.

Returns
  • the total horizontal range represented by the horizontal scrollbar

protected void dispatchSetPressed (boolean pressed)

Added in API level 1

Dispatch setPressed to all of this View's children.

Parameters
pressed The new pressed state

protected ViewGroup.LayoutParams generateDefaultLayoutParams ()

Added in API level 1

Returns a set of default layout parameters. These parameters are requested when the View passed to addView(View) has no layout parameters already set. If null is returned, an exception is thrown from addView.

Returns
  • a set of default layout parameters or null

protected ViewGroup.LayoutParams generateLayoutParams (ViewGroup.LayoutParams p)

Added in API level 1

Returns a safe set of layout parameters based on the supplied layout params. When a ViewGroup is passed a View whose layout params do not pass the test of checkLayoutParams(android.view.ViewGroup.LayoutParams), this method is invoked. This method should return a new set of layout params suitable for this ViewGroup, possibly by copying the appropriate attributes from the specified set of layout params.

Parameters
p The layout parameters to convert into a suitable set of layout parameters for this ViewGroup.
Returns

protected int getChildDrawingOrder (int childCount, int i)

Added in API level 1

Returns the index of the child to draw for this iteration. Override this if you want to change the drawing order of children. By default, it returns i.

NOTE: In order for this method to be called, you must enable child ordering first by calling setChildrenDrawingOrderEnabled(boolean).

Parameters
i The current iteration.
Returns
  • The index of the child to draw this iteration.

protected boolean getChildStaticTransformation (View child, Transformation t)

Added in API level 1

Sets t to be the static transformation of the child, if set, returning a boolean to indicate whether a static transform was set. The default implementation simply returns false; subclasses may override this method for different behavior. setStaticTransformationsEnabled(boolean) must be set to true for this method to be called.

Parameters
child The child view whose static transform is being requested
t The Transformation which will hold the result
Returns
  • true if the transformation was set, false otherwise

protected ContextMenu.ContextMenuInfo getContextMenuInfo ()

Added in API level 1

Views should implement this if they have extra information to associate with the context menu. The return result is supplied as a parameter to the onCreateContextMenu(ContextMenu, View, ContextMenuInfo) callback.

Returns
  • Extra information about the item for which the context menu should be shown. This information will vary across different subclasses of View.

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

Added in API level 1

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.

Parameters
gainFocus True if the View has focus; false otherwise.
direction The direction focus has moved when requestFocus() is called to give this view focus. Values are FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, FOCUS_RIGHT, FOCUS_FORWARD, or FOCUS_BACKWARD. It may not always apply, in which case use the default.
previouslyFocusedRect 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.

protected void onLayout (boolean changed, int l, int t, int r, int b)

Added in API level 1

Called from layout when this view should assign a size and position to each of its children. Derived classes with children should override this method and call layout on each of their children.

Parameters
changed This is a new size or position for this view
l Left position, relative to parent
t Top position, relative to parent
r Right position, relative to parent
b Bottom position, relative to parent