Keyframe
public
abstract
class
Keyframe
extends Object
implements
Cloneable
| java.lang.Object | |
| ↳ | android.animation.Keyframe |
This class holds a time/value pair for an animation. The Keyframe class is used
by ValueAnimator to define the values that the animation target will have over the course
of the animation. As the time proceeds from one keyframe to the other, the value of the
target object will animate between the value at the previous keyframe and the value at the
next keyframe. Each keyframe also holds an optional TimeInterpolator
object, which defines the time interpolation over the intervalue preceding the keyframe.
The Keyframe class itself is abstract. The type-specific factory methods will return
a subclass of Keyframe specific to the type of value being stored. This is done to improve
performance when dealing with the most common cases (e.g., float and
int values). Other types will fall into a more general Keyframe class that
treats its values as Objects. Unless your animation requires dealing with a custom type
or a data structure that needs to be animated directly (and evaluated using an implementation
of TypeEvaluator), you should stick to using float and int as animations using those
types have lower runtime overhead than other types.
Summary
Public constructors | |
|---|---|
Keyframe()
|
|
Public methods | |
|---|---|
abstract
Keyframe
|
clone()
Creates and returns a copy of this object. |
float
|
getFraction()
Gets the time for this keyframe, as a fraction of the overall animation duration. |
TimeInterpolator
|
getInterpolator()
Gets the optional interpolator for this Keyframe. |
Class<T>
|
getType()
Gets the type of keyframe. |
abstract
Object
|
getValue()
Gets the value for this Keyframe. |
boolean
|
hasValue()
Indicates whether this keyframe has a valid value. |
static
Keyframe
|
ofFloat(float fraction)
Constructs a Keyframe object with the given time. |
static
Keyframe
|
ofFloat(float fraction, float value)
Constructs a Keyframe object with the given time and value. |
static
Keyframe
|
ofInt(float fraction, int value)
Constructs a Keyframe object with the given time and value. |
static
Keyframe
|
ofInt(float fraction)
Constructs a Keyframe object with the given time. |
static
Keyframe
|
ofObject(float fraction, Object value)
Constructs a Keyframe object with the given time and value. |
static
Keyframe
|
ofObject(float fraction)
Constructs a Keyframe object with the given time. |
void
|
setFraction(float fraction)
Sets the time for this keyframe, as a fraction of the overall animation duration. |
void
|
setInterpolator(TimeInterpolator interpolator)
Sets the optional interpolator for this Keyframe. |
abstract
void
|
setValue(Object value)
Sets the value for this Keyframe. |
Inherited methods | |
|---|---|
Public constructors
Keyframe
public Keyframe ()
Public methods
clone
public abstract Keyframe clone ()
Creates and returns a copy of this object. The precise meaning
of "copy" may depend on the class of the object. The general
intent is that, for any object x, the expression:
will be true, and that the expression:
will be
true, but these are not absolute requirements.
While it is typically the case that:
will be
true, this is not an absolute requirement.
By convention, the returned object should be obtained by calling
super.clone. If a class and all of its superclasses (except
Object) obey this convention, it will be the case that
x.clone().getClass() == x.getClass().
By convention, the object returned by this method should be independent
of this object (which is being cloned). To achieve this independence,
it may be necessary to modify one or more fields of the object returned
by super.clone before returning it. Typically, this means
copying any mutable objects that comprise the internal "deep structure"
of the object being cloned and replacing the references to these
objects with references to the copies. If a class contains only
primitive fields or references to immutable objects, then it is usually
the case that no fields in the object returned by super.clone
need to be modified.
| Returns | |
|---|---|
Keyframe |
a clone of this instance. |
getFraction
public float getFraction ()
Gets the time for this keyframe, as a fraction of the overall animation duration.
| Returns | |
|---|---|
float |
The time associated with this keyframe, as a fraction of the overall animation duration. This should be a value between 0 and 1. |
getInterpolator
public TimeInterpolator getInterpolator ()
Gets the optional interpolator for this Keyframe. A value of null indicates
that there is no interpolation, which is the same as linear interpolation.
| Returns | |
|---|---|
TimeInterpolator |
The optional interpolator for this Keyframe. |
getType
public Class<T> getType ()
Gets the type of keyframe. This information is used by ValueAnimator to determine the type of
TypeEvaluator to use when calculating values between keyframes. The type is based
on the type of Keyframe created.
| Returns | |
|---|---|
Class<T> |
The type of the value stored in the Keyframe. |
getValue
public abstract Object getValue ()
Gets the value for this Keyframe.
| Returns | |
|---|---|
Object |
The value for this Keyframe. |
hasValue
public boolean hasValue ()
Indicates whether this keyframe has a valid value. This method is called internally when
an ObjectAnimator first starts; keyframes without values are assigned values at
that time by deriving the value for the property from the target object.
| Returns | |
|---|---|
boolean |
boolean Whether this object has a value assigned. |
ofFloat
public static Keyframe ofFloat (float fraction)
Constructs a Keyframe object with the given time. The value at this time will be derived
from the target object when the animation first starts (note that this implies that keyframes
with no initial value must be used as part of an ObjectAnimator).
The time defines the
time, as a proportion of an overall animation's duration, at which the value will hold true
for the animation. The value for the animation between keyframes will be calculated as
an interpolation between the values at those keyframes.
| Parameters | |
|---|---|
fraction |
float: The time, expressed as a value between 0 and 1, representing the fraction
of time elapsed of the overall animation duration. |
| Returns | |
|---|---|
Keyframe |
|
ofFloat
public static Keyframe ofFloat (float fraction, float value)
Constructs a Keyframe object with the given time and value. The time defines the time, as a proportion of an overall animation's duration, at which the value will hold true for the animation. The value for the animation between keyframes will be calculated as an interpolation between the values at those keyframes.
| Parameters | |
|---|---|
fraction |
float: The time, expressed as a value between 0 and 1, representing the fraction
of time elapsed of the overall animation duration. |
value |
float: The value that the object will animate to as the animation time approaches
the time in this keyframe, and the value animated from as the time passes the time in
this keyframe. |
| Returns | |
|---|---|
Keyframe |
|
ofInt
public static Keyframe ofInt (float fraction, int value)
Constructs a Keyframe object with the given time and value. The time defines the time, as a proportion of an overall animation's duration, at which the value will hold true for the animation. The value for the animation between keyframes will be calculated as an interpolation between the values at those keyframes.
| Parameters | |
|---|---|
fraction |
float: The time, expressed as a value between 0 and 1, representing the fraction
of time elapsed of the overall animation duration. |
value |
int: The value that the object will animate to as the animation time approaches
the time in this keyframe, and the value animated from as the time passes the time in
this keyframe. |
| Returns | |
|---|---|
Keyframe |
|
ofInt
public static Keyframe ofInt (float fraction)
Constructs a Keyframe object with the given time. The value at this time will be derived
from the target object when the animation first starts (note that this implies that keyframes
with no initial value must be used as part of an ObjectAnimator).
The time defines the
time, as a proportion of an overall animation's duration, at which the value will hold true
for the animation. The value for the animation between keyframes will be calculated as
an interpolation between the values at those keyframes.
| Parameters | |
|---|---|
fraction |
float: The time, expressed as a value between 0 and 1, representing the fraction
of time elapsed of the overall animation duration. |
| Returns | |
|---|---|
Keyframe |
|
ofObject
public static Keyframe ofObject (float fraction, Object value)
Constructs a Keyframe object with the given time and value. The time defines the time, as a proportion of an overall animation's duration, at which the value will hold true for the animation. The value for the animation between keyframes will be calculated as an interpolation between the values at those keyframes.
| Parameters | |
|---|---|
fraction |
float: The time, expressed as a value between 0 and 1, representing the fraction
of time elapsed of the overall animation duration. |
value |
Object: The value that the object will animate to as the animation time approaches
the time in this keyframe, and the value animated from as the time passes the time in
this keyframe. |
| Returns | |
|---|---|
Keyframe |
|
ofObject
public static Keyframe ofObject (float fraction)
Constructs a Keyframe object with the given time. The value at this time will be derived
from the target object when the animation first starts (note that this implies that keyframes
with no initial value must be used as part of an ObjectAnimator).
The time defines the
time, as a proportion of an overall animation's duration, at which the value will hold true
for the animation. The value for the animation between keyframes will be calculated as
an interpolation between the values at those keyframes.
| Parameters | |
|---|---|
fraction |
float: The time, expressed as a value between 0 and 1, representing the fraction
of time elapsed of the overall animation duration. |
| Returns | |
|---|---|
Keyframe |
|
setFraction
public void setFraction (float fraction)
Sets the time for this keyframe, as a fraction of the overall animation duration.
| Parameters | |
|---|---|
fraction |
float: time associated with this keyframe, as a fraction of the overall animation
duration. This should be a value between 0 and 1. |
setInterpolator
public void setInterpolator (TimeInterpolator interpolator)
Sets the optional interpolator for this Keyframe. A value of null indicates
that there is no interpolation, which is the same as linear interpolation.
| Parameters | |
|---|---|
interpolator |
TimeInterpolator |
| Returns | |
|---|---|
void |
The optional interpolator for this Keyframe. |
setValue
public abstract void setValue (Object value)
Sets the value for this Keyframe.
| Parameters | |
|---|---|
value |
Object: value for this Keyframe. |