FlingAnimation
public final class FlingAnimation extends DynamicAnimation
| java.lang.Object | ||
| ↳ | androidx.dynamicanimation.animation.DynamicAnimation | |
| ↳ | androidx.dynamicanimation.animation.FlingAnimation | |
Fling animation is an animation that continues an initial momentum (most often from gesture velocity) and gradually slows down. The fling animation will come to a stop when the velocity of the animation is below the threshold derived from setMinimumVisibleChange, or when the value of the animation has gone beyond the min or max value defined via setMinValue or setMaxValue. It is recommended to restrict the fling animation with min and/or max value, such that the animation can end when it goes beyond screen bounds, thus preserving CPU cycles and resources.
For example, you can create a fling animation that animates the translationX of a view:
FlingAnimation flingAnim = new FlingAnimation(view, DynamicAnimation.TRANSLATION_X)
// Sets the start velocity to -2000 (pixel/s)
.setStartVelocity(-2000)
// Optional but recommended to set a reasonable min and max range for the animation.
// In this particular case, we set the min and max to -200 and 2000 respectively.
.setMinValue(-200).setMaxValue(2000);
flingAnim.start();
Summary
Public constructors |
|---|
FlingAnimation(FloatValueHolder floatValueHolder)This creates a FlingAnimation that animates a |
<K> FlingAnimation(K object, FloatPropertyCompat<K> property)This creates a FlingAnimation that animates the property of the given object. |
Public methods |
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|---|---|
float |
Returns the friction being set on the animation via |
FlingAnimation |
setFriction(@FloatRange(from = 0.0, fromInclusive = false) float friction)Sets the friction for the fling animation. |
FlingAnimation |
setMaxValue(float maxValue)Sets the max value of the animation. |
FlingAnimation |
setMinValue(float minValue)Sets the min value of the animation. |
FlingAnimation |
setStartVelocity(float startVelocity)Start velocity of the animation. |
Inherited Constants |
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Inherited methods |
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Public constructors
FlingAnimation
public FlingAnimation(FloatValueHolder floatValueHolder)
This creates a FlingAnimation that animates a FloatValueHolder instance. During the animation, the FloatValueHolder instance will be updated via setValue each frame. The caller can obtain the up-to-date animation value via getValue.
Note: changing the value in the FloatValueHolder via setValue outside of the animation during an animation run will not have any effect on the on-going animation.
| Parameters | |
|---|---|
FloatValueHolder floatValueHolder |
the property to be animated |
FlingAnimation
public <K> FlingAnimation(K object, FloatPropertyCompat<K> property)
This creates a FlingAnimation that animates the property of the given object.
| Parameters | |
|---|---|
<K> |
the class on which the property is declared |
K object |
the Object whose property will be animated |
FloatPropertyCompat<K> property |
the property to be animated |
Public methods
getFriction
public float getFriction()
Returns the friction being set on the animation via setFriction. If the friction has not been set, the default friction of 1 will be returned.
| Returns | |
|---|---|
float |
friction being used in the animation |
setFriction
public FlingAnimation setFriction(@FloatRange(from = 0.0, fromInclusive = false) float friction)
Sets the friction for the fling animation. The greater the friction is, the sooner the animation will slow down. When not set, the friction defaults to 1.
| Parameters | |
|---|---|
@FloatRange(from = 0.0, fromInclusive = false) float friction |
the friction used in the animation |
| Returns | |
|---|---|
FlingAnimation |
the animation whose friction will be scaled |
| Throws | |
|---|---|
java.lang.IllegalArgumentException |
if the input friction is not positive |
setMaxValue
public FlingAnimation setMaxValue(float maxValue)
Sets the max value of the animation. When a fling animation reaches the max value, the animation will end immediately. Animations will not animate beyond the max value.
| Parameters | |
|---|---|
float maxValue |
maximum value of the property to be animated |
| Returns | |
|---|---|
FlingAnimation |
the Animation whose max value is being set |
setMinValue
public FlingAnimation setMinValue(float minValue)
Sets the min value of the animation. When a fling animation reaches the min value, the animation will end immediately. Animations will not animate beyond the min value.
| Parameters | |
|---|---|
float minValue |
minimum value of the property to be animated |
| Returns | |
|---|---|
FlingAnimation |
the Animation whose min value is being set |
setStartVelocity
public FlingAnimation setStartVelocity(float startVelocity)
Start velocity of the animation. Default velocity is 0. Unit: pixel/second
A non-zero start velocity is required for a FlingAnimation. If no start velocity is set through setStartVelocity, the start velocity defaults to 0. In that case, the fling animation will consider itself done in the next frame.
Note when using a fixed value as the start velocity (as opposed to getting the velocity through touch events), it is recommended to define such a value in dp/second and convert it to pixel/second based on the density of the screen to achieve a consistent look across different screens.
To convert from dp/second to pixel/second:
float pixelPerSecond = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dpPerSecond,
getResources().getDisplayMetrics());
| Parameters | |
|---|---|
float startVelocity |
start velocity of the animation in pixel/second |
| Returns | |
|---|---|
FlingAnimation |
the Animation whose start velocity is being set |