Parallax

public abstract class Parallax<PropertyT extends Property>

Parallax tracks a list of dynamic Propertys typically representing foreground UI element positions on screen. Parallax keeps a list of ParallaxEffect objects which define rules to mapping property values to ParallaxTarget.

Example: // when Property "var1" changes from 15 to max value, perform parallax effect to // change myView's translationY from 0 to 100. Parallaxparallax = new Parallax

To create a ParallaxEffect, user calls addEffect with a list of PropertyMarkerValue which defines the range of Parallax.IntProperty or Parallax.FloatProperty. Then user adds ParallaxTarget into ParallaxEffect.

App may subclass Parallax.IntProperty or Parallax.FloatProperty to supply additional information about how to retrieve Property value. RecyclerViewParallax is a great example of Parallax implementation tracking child view positions on screen.

Restrictions of properties

• FloatProperty and IntProperty cannot be mixed in one Parallax
• Values must be in ascending order.
• If the UI element is unknown above screen, use UNKNOWN_BEFORE.
• if the UI element is unknown below screen, use UNKNOWN_AFTER.
• UNKNOWN_BEFORE and UNKNOWN_AFTER are not allowed to be next to each other.

Subclass must override updateValues to update property values and perform ParallaxEffects. Subclass may call updateValues automatically e.g. RecyclerViewParallax calls updateValues in RecyclerView scrolling. App might call updateValues manually when Parallax is unaware of the value change. For example, when a slide transition is running, RecyclerViewParallax is unaware of translation value changes; it's the app's responsibility to call updateValues in every frame of animation.

Summary

public Parallax()

public ParallaxEffect addEffect(Parallax.PropertyMarkerValue[] ranges)

public final PropertyT addProperty(String name)

public abstract PropertyT createProperty(String name, int index)

public List<ParallaxEffect> getEffects()

public abstract float getMaxValue()

public final List<PropertyT> getProperties()

public void removeAllEffects()

public void removeEffect(ParallaxEffect effect)

@CallSuper
public void updateValues()