SpringForce

public static final float DAMPING_RATIO_HIGH_BOUNCY = 0.2f

Damping ratio for a very bouncy spring. Note for under-damped springs (i.e. damping ratio <1), the lower the damping ratio, the more bouncy the spring.

public static final float DAMPING_RATIO_LOW_BOUNCY = 0.75f

Damping ratio for a spring with low bounciness. Note for under-damped springs (i.e. damping ratio <1), the lower the damping ratio, the higher the bounciness.

public static final float DAMPING_RATIO_MEDIUM_BOUNCY = 0.5f

Damping ratio for a medium bouncy spring. This is also the default damping ratio for spring force. Note for under-damped springs (i.e. damping ratio <1), the lower the damping ratio, the more bouncy the spring.

public static final float DAMPING_RATIO_NO_BOUNCY = 1.0f

Damping ratio for a spring with no bounciness. This damping ratio will create a critically damped spring that returns to equilibrium within the shortest amount of time without oscillating.

public static final float STIFFNESS_HIGH = 10000.0f

Stiffness constant for extremely stiff spring.

public static final float STIFFNESS_LOW = 200.0f

Stiffness constant for a spring with low stiffness.

public static final float STIFFNESS_MEDIUM = 1500.0f

Stiffness constant for medium stiff spring. This is the default stiffness for spring force.

public static final float STIFFNESS_VERY_LOW = 50.0f

Stiffness constant for a spring with very low stiffness.

public SpringForce()

Creates a spring force. Note that final position of the spring must be set through setFinalPosition before the spring animation starts.

public SpringForce(float finalPosition)

Creates a spring with a given final rest position.

public float getDampingRatio()

Returns the damping ratio of the spring.

public float getFinalPosition()

Returns the rest position of the spring.

public float getStiffness()

Gets the stiffness of the spring.

public SpringForce setDampingRatio(@FloatRange(from = 0.0) float dampingRatio)

Spring damping ratio describes how oscillations in a system decay after a disturbance.

When damping ratio >1 (over-damped), the object will quickly return to the rest position without overshooting. If damping ratio equals to 1 (i.e. critically damped), the object will return to equilibrium within the shortest amount of time. When damping ratio is less than 1 (i.e. under-damped), the mass tends to overshoot, and return, and overshoot again. Without any damping (i.e. damping ratio = 0), the mass will oscillate forever.

Default damping ratio is DAMPING_RATIO_MEDIUM_BOUNCY.

public SpringForce setFinalPosition(float finalPosition)

Sets the rest position of the spring.

public SpringForce setStiffness(@FloatRange(from = 0.0, fromInclusive = false) float stiffness)

Sets the stiffness of a spring. The more stiff a spring is, the more force it applies to the object attached when the spring is not at the final position. Default stiffness is STIFFNESS_MEDIUM.