Android
android.view.animation
public class

android.view.animation.LayoutAnimationController

java.lang.Object
android.view.animation.LayoutAnimationController

A layout animation controller is used to animated a layout's, or a view group's, children. Each child uses the same animation but for every one of them, the animation starts at a different time. A layout animation controller is used by ViewGroup to compute the delay by which each child's animation start must be offset. The delay is computed by using characteristics of each child, like its index in the view group. This standard implementation computes the delay by multiplying a fixed amount of miliseconds by the index of the child in its parent view group. Subclasses are supposed to override getDelayForView(android.view.View) to implement a different way of computing the delay. For instance, a GridLayoutAnimationController will compute the delay based on the column and row indices of the child in its parent view group. Information used to compute the animation delay of each child are stored in an instance of LayoutAnimationController.AnimationParameters, itself stored in the ViewGroup.LayoutParams of the view.

Nested Classes
LayoutAnimationController.AnimationParameters The set of parameters that has to be attached to each view contained in the view group animated by the layout animation controller. 
Known Direct Subclasses

Summary

XML Attributes

Attribute name Related methods  
android:animation setAnimation(Animation)
 
Animation to use on each child. 
android:animationOrder setOrder(int)
 
The order in which the animations will be started. 
android:delay   Fraction of the animation duration used to delay the beginning of the animation of each child. 
android:interpolator setInterpolator(Context,int)
 
Interpolator used to interpolate the delay between the start of each animation. 

Constants

      Value  
int  ORDER_NORMAL  Distributes the animation delays in the order in which view were added to their view group.  0x00000000 
int  ORDER_RANDOM  Randomly distributes the animation delays.  0x00000002 
int  ORDER_REVERSE  Distributes the animation delays in the reverse order in which view were added to their view group.  0x00000001 

Fields

protected      Animation  mAnimation  The animation applied on each child of the view group on which this layout animation controller is set. 
protected      Interpolator  mInterpolator  The interpolator used to interpolate the delays. 
protected      Random  mRandomizer  The randomizer used when the order is set to random. 

Public Constructors

            LayoutAnimationController(Context context, AttributeSet attrs)
Creates a new layout animation controller from external resources.
            LayoutAnimationController(Animation animation)
Creates a new layout animation controller with a delay of 50% and the specified animation.
            LayoutAnimationController(Animation animation, float delay)
Creates a new layout animation controller with the specified delay and the specified animation.

Public Methods

          Animation  getAnimation()
Returns the animation applied to each child of the view group on which this controller is set.
    final      Animation  getAnimationForView(View view)
Returns the animation to be applied to the specified view.
          float  getDelay()
Returns the delay by which the children's animation are offset.
          Interpolator  getInterpolator()
Returns the interpolator used to interpolate the delays between the children.
          int  getOrder()
Returns the order used to compute the delay of each child's animation.
          boolean  isDone()
Indicates whether the layout animation is over or not.
          void  setAnimation(Context context, int resourceID)
Sets the animation to be run on each child of the view group on which this layout animation controller is .
          void  setAnimation(Animation animation)
Sets the animation to be run on each child of the view group on which this layout animation controller is .
          void  setDelay(float delay)
Sets the delay, as a fraction of the animation duration, by which the children's animations are offset.
          void  setInterpolator(Interpolator interpolator)
Sets the interpolator used to interpolate the delays between the children.
          void  setInterpolator(Context context, int resourceID)
Sets the interpolator used to interpolate the delays between the children.
          void  setOrder(int order)
Sets the order used to compute the delay of each child's animation.
          void  start()
Starts the animation.
          boolean  willOverlap()
Indicates whether two children's animations will overlap.

Protected Methods

          long  getDelayForView(View view)
Returns the amount of milliseconds by which the specified view's animation must be delayed or offset.
          int  getTransformedIndex(LayoutAnimationController.AnimationParameters params)
Transforms the index stored in LayoutAnimationController.AnimationParameters by the order returned by getOrder().
Methods inherited from class java.lang.Object

Details

XML Attributes

android:animation

Animation to use on each child.

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

This corresponds to the global attribute resource symbol animation.

Related Methods

android:animationOrder

The order in which the animations will be started.

Must be one of the following constant values.

ConstantValueDescription
normal0 Animations are started in the natural order.
reverse1 Animations are started in the reverse order.
random2 Animations are started randomly.

This corresponds to the global attribute resource symbol animationOrder.

Related Methods

android:delay

Fraction of the animation duration used to delay the beginning of the animation of each child.

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

May be a fractional value, which is a floating point number appended with either % or %p, such as "14.5%". The % suffix always means a percentage of the base size; the optional %p suffix provides a size relative to some parent container.

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 delay.

Related Methods

android:interpolator

Interpolator used to interpolate the delay between the start of each animation.

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

This corresponds to the global attribute resource symbol interpolator.

Constants

public static final int ORDER_NORMAL

Distributes the animation delays in the order in which view were added to their view group.
Constant Value: 0 (0x00000000)

public static final int ORDER_RANDOM

Randomly distributes the animation delays.
Constant Value: 2 (0x00000002)

public static final int ORDER_REVERSE

Distributes the animation delays in the reverse order in which view were added to their view group.
Constant Value: 1 (0x00000001)

Fields

protected Animation mAnimation

The animation applied on each child of the view group on which this layout animation controller is set.

protected Interpolator mInterpolator

The interpolator used to interpolate the delays.

protected Random mRandomizer

The randomizer used when the order is set to random. Subclasses should use this object to avoid creating their own.

Public Constructors

public LayoutAnimationController(Context context, AttributeSet attrs)

Creates a new layout animation controller from external resources.

Parameters

context the Context the view group is running in, through which it can access the resources
attrs the attributes of the XML tag that is inflating the layout animation controller

public LayoutAnimationController(Animation animation)

Creates a new layout animation controller with a delay of 50% and the specified animation.

Parameters

animation the animation to use on each child of the view group

public LayoutAnimationController(Animation animation, float delay)

Creates a new layout animation controller with the specified delay and the specified animation.

Parameters

animation the animation to use on each child of the view group
delay the delay by which each child's animation must be offset

Public Methods

public Animation getAnimation()

Returns the animation applied to each child of the view group on which this controller is set.

Returns

public final Animation getAnimationForView(View view)

Returns the animation to be applied to the specified view. The returned animation is delayed by an offset computed according to the information provided by LayoutAnimationController.AnimationParameters. This method is called by view groups to obtain the animation to set on a specific child.

Parameters

view the view to animate

Returns

public float getDelay()

Returns the delay by which the children's animation are offset. The delay is expressed as a fraction of the animation duration.

Returns

  • a fraction of the animation duration

See Also

public Interpolator getInterpolator()

Returns the interpolator used to interpolate the delays between the children.

Returns

public int getOrder()

Returns the order used to compute the delay of each child's animation.

Related XML Attributes

Returns

public boolean isDone()

Indicates whether the layout animation is over or not. A layout animation is considered done when the animation with the longest delay is done.

Returns

  • true if all of the children's animations are over, false otherwise

public void setAnimation(Context context, int resourceID)

Sets the animation to be run on each child of the view group on which this layout animation controller is .

Related XML Attributes

Parameters

context the context from which the animation must be inflated
resourceID the resource identifier of the animation

public void setAnimation(Animation animation)

Sets the animation to be run on each child of the view group on which this layout animation controller is .

Related XML Attributes

Parameters

animation the animation to run on each child of the view group

public void setDelay(float delay)

Sets the delay, as a fraction of the animation duration, by which the children's animations are offset. The general formula is:
 child animation delay = child index * delay * animation duration
 

Parameters

delay a fraction of the animation duration

See Also

public void setInterpolator(Interpolator interpolator)

Sets the interpolator used to interpolate the delays between the children.

Related XML Attributes

Parameters

interpolator the interpolator

public void setInterpolator(Context context, int resourceID)

Sets the interpolator used to interpolate the delays between the children.

Related XML Attributes

Parameters

context the context from which the interpolator must be inflated
resourceID the resource identifier of the interpolator

public void setOrder(int order)

Sets the order used to compute the delay of each child's animation.

Related XML Attributes

Parameters

order one of ORDER_NORMAL, ORDER_REVERSE or ORDER_RANDOM

public void start()

Starts the animation.

public boolean willOverlap()

Indicates whether two children's animations will overlap. Animations overlap when the delay is lower than 100% (or 1.0).

Returns

  • true if animations will overlap, false otherwise

Protected Methods

protected long getDelayForView(View view)

Returns the amount of milliseconds by which the specified view's animation must be delayed or offset. Subclasses should override this method to return a suitable value. This implementation returns child animation delay milliseconds where:
 child animation delay = child index * delay
 
The index is retrieved from the LayoutAnimationController.AnimationParameters found in the view's ViewGroup.LayoutParams.

Parameters

view the view for which to obtain the animation's delay

Returns

  • a delay in milliseconds

protected int getTransformedIndex(LayoutAnimationController.AnimationParameters params)

Transforms the index stored in LayoutAnimationController.AnimationParameters by the order returned by getOrder(). Subclasses should override this method to provide additional support for other types of ordering. This method should be invoked by getDelayForView(android.view.View) prior to any computation.

Parameters

params the animation parameters containing the index

Returns

  • a transformed index
Copyright 2007 Google Inc. Build 0.9_r1-98467 - 14 Aug 2008 18:56