android.view.animation
Class LayoutAnimationController

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

Direct Known Subclasses:

GridLayoutAnimationController

public class LayoutAnimationController
extends Object

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 Class Summary

static class

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.

Field Summary

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.
static int	ORDER_NORMAL Distributes the animation delays in the order in which view were added to their view group.
static int	ORDER_RANDOM Randomly distributes the animation delays.
static int	ORDER_REVERSE Distributes the animation delays in the reverse order in which view were added to their view group.

Constructor Summary

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.

LayoutAnimationController(Context context, AttributeSet attrs)
Creates a new layout animation controller from external resources.

Method Summary

Animation	getAnimation() Returns the animation applied to each child of the view group on which this controller is set.
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.
protected long	getDelayForView(View view) Returns the amount of milliseconds by which the specified view's animation must be delayed or 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.
protected int	getTransformedIndex(LayoutAnimationController.AnimationParameters params) Transforms the index stored in LayoutAnimationController.AnimationParameters by the order returned by getOrder().
boolean	isDone() Indicates whether the layout animation is over or not.
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	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	setDelay(float delay) Sets the delay, as a fraction of the animation duration, by which the children's animations are offset.
void	setInterpolator(Context context, int resourceID) Sets the interpolator used to interpolate the delays between the children.
void	setInterpolator(Interpolator interpolator) 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.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ORDER_NORMAL

public static final int ORDER_NORMAL

Distributes the animation delays in the order in which view were added to their view group.

See Also:

Constant Field Values

ORDER_REVERSE

public static final int ORDER_REVERSE

Distributes the animation delays in the reverse order in which view were added to their view group.

See Also:

Constant Field Values

ORDER_RANDOM

public static final int ORDER_RANDOM

Randomly distributes the animation delays.

See Also:

Constant Field Values

mAnimation

protected Animation mAnimation

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

mRandomizer

protected Random mRandomizer

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

mInterpolator

protected Interpolator mInterpolator

The interpolator used to interpolate the delays.

Constructor Detail

LayoutAnimationController

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

LayoutAnimationController

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

LayoutAnimationController

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

Method Detail

getOrder

public int getOrder()

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

Returns:

one of ORDER_NORMAL, ORDER_REVERSE or {@link #ORDER_RANDOM)

setOrder

public void setOrder(int order)

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

Parameters:

order - one of ORDER_NORMAL, ORDER_REVERSE or ORDER_RANDOM

setAnimation

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 .

Parameters:

context - the context from which the animation must be inflated

resourceID - the resource identifier of the animation

See Also:

setAnimation(Animation), getAnimation()

setAnimation

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 .

Parameters:

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

See Also:

setAnimation(android.content.Context, int), getAnimation()

getAnimation

public Animation getAnimation()

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

Returns:

an Animation instance

See Also:

setAnimation(android.content.Context, int), setAnimation(Animation)

setInterpolator

public void setInterpolator(Context context,
                            int resourceID)

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

Parameters:

context - the context from which the interpolator must be inflated

resourceID - the resource identifier of the interpolator

See Also:

getInterpolator(), setInterpolator(Interpolator)

setInterpolator

public void setInterpolator(Interpolator interpolator)

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

Parameters:

interpolator - the interpolator

See Also:

getInterpolator(), setInterpolator(Interpolator)

getInterpolator

public Interpolator getInterpolator()

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

Returns:

an Interpolator

getDelay

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:

setDelay(float)

setDelay

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:

getDelay()

willOverlap

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

start

public void start()

Starts the animation.

getAnimationForView

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:

an animation delayed by the number of milliseconds returned by getDelayForView(android.view.View)

See Also:

getDelay(), setDelay(float), getDelayForView(android.view.View)

isDone

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

getDelayForView

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

See Also:

getAnimationForView(android.view.View), getDelay(), getTransformedIndex(android.view.animation.LayoutAnimationController.AnimationParameters), ViewGroup.LayoutParams

getTransformedIndex

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