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/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.animation;
import android.view.animation.Interpolator;
/**
* This class holds a time/value pair for an animation. The Keyframe class is used
* by {@link Animator} 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 option {@link android.view.animation.Interpolator}
* object, which defines the time interpolation over the intervalue preceding the keyframe.
*/
public class Keyframe {
/**
* The time at which mValue will hold true.
*/
private float mFraction;
/**
* The value of the animation at the time mFraction.
*/
private Object mValue;
/**
* The type of the value in this Keyframe. This type is determined at construction time,
* based on the type of the <code>value</code> object passed into the constructor.
*/
private Class mValueType;
/**
* The optional time interpolator for the interval preceding this keyframe. A null interpolator
* (the default) results in linear interpolation over the interval.
*/
private Interpolator mInterpolator = null;
/**
* Private constructor, called from the public constructors with the additional
* <code>valueType</code> parameter.
*
* @param fraction The time, expressed as a value between 0 and 1, representing the fraction
* of time elapsed of the overall animation duration.
* @param value The value that the object will animate to as the animation time approaches
* the time in this keyframe, and the the value animated from as the time passes the time in
* this keyframe.
* @param valueType The type of the <code>value</code> object. This is used by the
* {@link #getValue()} functionm, which is queried by {@link Animator} to determine
* the type of {@link TypeEvaluator} to use to interpolate between values.
*/
private Keyframe(float fraction, Object value, Class valueType) {
mFraction = fraction;
mValue = value;
mValueType = valueType;
}
/**
* 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.
*
* @param fraction The time, expressed as a value between 0 and 1, representing the fraction
* of time elapsed of the overall animation duration.
* @param value The value that the object will animate to as the animation time approaches
* the time in this keyframe, and the the value animated from as the time passes the time in
* this keyframe.
*/
public Keyframe(float fraction, Object value) {
this(fraction, value, Object.class);
}
/**
* Constructs a Keyframe object with the given time and integer 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.
*
* @param fraction The time, expressed as a value between 0 and 1, representing the fraction
* of time elapsed of the overall animation duration.
* @param value The value that the object will animate to as the animation time approaches
* the time in this keyframe, and the the value animated from as the time passes the time in
* this keyframe.
*/
public Keyframe(float fraction, int value) {
this(fraction, value, int.class);
}
/**
* Constructs a Keyframe object with the given time and float 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.
*
* @param fraction The time, expressed as a value between 0 and 1, representing the fraction
* of time elapsed of the overall animation duration.
* @param value The value that the object will animate to as the animation time approaches
* the time in this keyframe, and the the value animated from as the time passes the time in
* this keyframe.
*/
public Keyframe(float fraction, float value) {
this(fraction, value, float.class);
}
/**
* Constructs a Keyframe object with the given time and double 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.
*
* @param fraction The time, expressed as a value between 0 and 1, representing the fraction
* of time elapsed of the overall animation duration.
* @param value The value that the object will animate to as the animation time approaches
* the time in this keyframe, and the the value animated from as the time passes the time in
* this keyframe.
*/
public Keyframe(float fraction, double value) {
this(fraction, value, double.class);
}
/**
* Gets the value for this Keyframe.
*
* @return The value for this Keyframe.
*/
public Object getValue() {
return mValue;
}
/**
* Sets the value for this Keyframe.
*
* @param value value for this Keyframe.
*/
public void setValue(Object value) {
mValue = value;
}
/**
* Gets the time for this keyframe, as a fraction of the overall animation duration.
*
* @return The time associated with this keyframe, as a fraction of the overall animation
* duration. This should be a value between 0 and 1.
*/
public float getFraction() {
return mFraction;
}
/**
* Sets the time for this keyframe, as a fraction of the overall animation duration.
*
* @param fraction time associated with this keyframe, as a fraction of the overall animation
* duration. This should be a value between 0 and 1.
*/
public void setFraction(float fraction) {
mFraction = fraction;
}
/**
* Gets the optional interpolator for this Keyframe. A value of <code>null</code> indicates
* that there is no interpolation, which is the same as linear interpolation.
*
* @return The optional interpolator for this Keyframe.
*/
public Interpolator getInterpolator() {
return mInterpolator;
}
/**
* Sets the optional interpolator for this Keyframe. A value of <code>null</code> indicates
* that there is no interpolation, which is the same as linear interpolation.
*
* @return The optional interpolator for this Keyframe.
*/
public void setInterpolator(Interpolator interpolator) {
mInterpolator = interpolator;
}
/**
* Gets the type of keyframe. This information is used by Animator to determine the type of
* {@link TypeEvaluator} to use when calculating values between keyframes. The type is based
* on the type of Keyframe created.
*
* @return The type of the value stored in the Keyframe.
*/
public Class getType() {
return mValueType;
}
}
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