Fade

Artifact: androidx.transition:transition

Added in 1.0.0

Kotlin |Java

class Fade : Visibility

kotlin.Any
↳	androidx.transition.Transition
	↳	androidx.transition.Visibility
		↳	androidx.transition.Fade

This transition tracks changes to the visibility of target views in the start and end scenes and fades views in or out when they become visible or non-visible. Visibility is determined by both the setVisibility state of the view as well as whether it is parented in the current view hierarchy.

The ability of this transition to fade out a particular view, and the way that that fading operation takes place, is based on the situation of the view in the view hierarchy. For example, if a view was simply removed from its parent, then the view will be added into a while fading. If a visible view is changed to be GONE or INVISIBLE, then the visibility will be changed to VISIBLE for the duration of the animation. However, if a view is in a hierarchy which is also altering its visibility, the situation can be more complicated. In general, if a view that is no longer in the hierarchy in the end scene still has a parent (so its parent hierarchy was removed, but it was not removed from its parent), then it will be left alone to avoid side-effects from improperly removing it from its parent. The only exception to this is if the previous Scene was created from a layout resource file, then it is considered safe to un-parent the starting scene view in order to fade it out.

A Fade transition can be described in a resource file by using the tag fade, along with the standard attributes of Fade and Transition.

Summary

Constants
`const Int`	`IN = 1` Fading mode used in `Fade` to make the transition operate on targets that are appearing.
`const Int`	`OUT = 2` Fading mode used in `Fade` to make the transition operate on targets that are disappearing.

Public constructors
`Fade()` Constructs a Fade transition that will fade targets in and out.
`Fade(fadingMode: Int)` Constructs a Fade transition that will fade targets in and/or out, according to the value of fadingMode.
`Fade(context: Context, attrs: AttributeSet)`

Public functions
`Unit`	`captureStartValues(transitionValues: TransitionValues)` Captures the values in the start scene for the properties that this transition monitors.
`Boolean`	`isSeekingSupported()` Returns `true` if the Transition can be used by `controlDelayedTransition`.
`Animator?`	`onAppear( sceneRoot: ViewGroup, view: View, startValues: TransitionValues?, endValues: TransitionValues? )` The default implementation of this method returns a null Animator.
`Animator?`	`onDisappear( sceneRoot: ViewGroup, view: View, startValues: TransitionValues?, endValues: TransitionValues? )` The default implementation of this method returns a null Animator.

Inherited Constants

From androidx.transition.Transition

`const Int`	`MATCH_ID = 3` With `setMatchOrder`, chooses to match by `getId`.
`const Int`	`MATCH_INSTANCE = 1` With `setMatchOrder`, chooses to match by View instance.
`const Int`	`MATCH_ITEM_ID = 4` With `setMatchOrder`, chooses to match by the `android.widget.Adapter` item id.
`const Int`	`MATCH_NAME = 2` With `setMatchOrder`, chooses to match by `getTransitionName`.

From androidx.transition.Visibility

`const Int`	`MODE_IN = 1` Mode used in `setMode` to make the transition operate on targets that are appearing.
`const Int`	`MODE_OUT = 2` Mode used in `setMode` to make the transition operate on targets that are disappearing.

Inherited functions

From androidx.transition.Transition

`Transition`	`addListener(listener: Transition.TransitionListener)` Adds a listener to the set of listeners that are sent events through the life of an animation, such as start, repeat, and end.
`Transition`	`addTarget(targetId: @IdRes Int)` Adds the id of a target view that this Transition is interested in animating.
`Transition`	`addTarget(targetName: String)` Adds the transitionName of a target view that this Transition is interested in animating.
`Transition`	`addTarget(targetType: Class<Any!>)` Adds the Class of a target view that this Transition is interested in animating.
`Transition`	`addTarget(target: View)` Sets the target view instances that this Transition is interested in animating.
`Transition`	`clone()`
`Transition`	`excludeChildren(targetId: @IdRes Int, exclude: Boolean)` Whether to add the children of the given id to the list of targets to exclude from this transition.
`Transition`	`excludeChildren(target: View, exclude: Boolean)` Whether to add the children of given target to the list of target children to exclude from this transition.
`Transition`	`excludeChildren(type: Class<Any!>, exclude: Boolean)` Whether to add the given type to the list of types whose children should be excluded from this transition.
`Transition`	`excludeTarget(targetId: @IdRes Int, exclude: Boolean)` Whether to add the given id to the list of target ids to exclude from this transition.
`Transition`	`excludeTarget(targetName: String, exclude: Boolean)` Whether to add the given transitionName to the list of target transitionNames to exclude from this transition.
`Transition`	`excludeTarget(target: View, exclude: Boolean)` Whether to add the given target to the list of targets to exclude from this transition.
`Transition`	`excludeTarget(type: Class<Any!>, exclude: Boolean)` Whether to add the given type to the list of types to exclude from this transition.
`Long`	`getDuration()` Returns the duration set on this transition.
`Rect?`	`getEpicenter()` Returns the epicenter as specified by the `android.transition.Transition.EpicenterCallback` or null if no callback exists.
`Transition.EpicenterCallback?`	`getEpicenterCallback()` Returns the callback used to find the epicenter of the Transition.
`TimeInterpolator?`	`getInterpolator()` Returns the interpolator set on this transition.
`String`	`getName()` Returns the name of this Transition.
`PathMotion`	`getPathMotion()` Returns the algorithm object used to interpolate along two dimensions.
`TransitionPropagation?`	`getPropagation()` Returns the `android.transition.TransitionPropagation` used to calculate Animator start delays.
`Transition`	`getRootTransition()` If this Transition is not part of a TransitionSet, this is returned.
`Long`	`getStartDelay()` Returns the startDelay set on this transition.
`(Mutable)List<Int!>`	`getTargetIds()` Returns the array of target IDs that this transition limits itself to tracking and animating.
`(Mutable)List<String!>?`	`getTargetNames()` Returns the list of target transitionNames that this transition limits itself to tracking and animating.
`(Mutable)List<Class<Any!>!>?`	`getTargetTypes()` Returns the list of target transitionNames that this transition limits itself to tracking and animating.
`(Mutable)List<View!>`	`getTargets()` Returns the array of target views that this transition limits itself to tracking and animating.
`TransitionValues?`	`getTransitionValues(view: View, start: Boolean)` This method can be called by transitions to get the TransitionValues for any particular view during the transition-playing process.
`Transition`	`removeListener(listener: Transition.TransitionListener)` Removes a listener from the set listening to this animation.
`Transition`	`removeTarget(target: Class<Any!>)` Removes the given target from the list of targets that this Transition is interested in animating.
`Transition`	`removeTarget(targetId: @IdRes Int)` Removes the given targetId from the list of ids that this Transition is interested in animating.
`Transition`	`removeTarget(targetName: String)` Removes the given targetName from the list of transitionNames that this Transition is interested in animating.
`Transition`	`removeTarget(target: View)` Removes the given target from the list of targets that this Transition is interested in animating.
`Transition`	`setDuration(duration: Long)` Sets the duration of this transition.
`Unit`	`setEpicenterCallback(epicenterCallback: Transition.EpicenterCallback?)` Sets the callback to use to find the epicenter of a Transition.
`Transition`	`setInterpolator(interpolator: TimeInterpolator?)` Sets the interpolator of this transition.
`Unit`	`setMatchOrder(matches: IntArray?)` Sets the order in which Transition matches View start and end values.
`Unit`	`setPathMotion(pathMotion: PathMotion?)` Sets the algorithm used to calculate two-dimensional interpolation.
`Unit`	`setPropagation(transitionPropagation: TransitionPropagation?)` Sets the method for determining Animator start delays.
`Transition`	`setStartDelay(startDelay: Long)` Sets the startDelay of this transition.
`String`	`toString()`

From androidx.transition.Visibility

`Unit`	`captureEndValues(transitionValues: TransitionValues)` Captures the values in the end scene for the properties that this transition monitors.
`Animator?`	`createAnimator( sceneRoot: ViewGroup, startValues: TransitionValues?, endValues: TransitionValues? )` This method creates an animation that will be run for this transition given the information in the startValues and endValues structures captured earlier for the start and end scenes.
`Int`	`getMode()` Returns whether appearing and/or disappearing Views are supported.
`Array<String!>?`	`getTransitionProperties()` Returns the set of property names used stored in the `TransitionValues` object passed into `captureStartValues` that this transition cares about for the purposes of canceling overlapping animations.
`Boolean`	`isTransitionRequired( startValues: TransitionValues?, endValues: TransitionValues? )` Returns whether or not the transition should create an Animator, based on the values captured during `captureStartValues` and `captureEndValues`.
`Boolean`	`isVisible(values: TransitionValues?)` Returns whether the view is 'visible' according to the given values object.
`Animator?`	`onAppear( sceneRoot: ViewGroup, startValues: TransitionValues?, startVisibility: Int, endValues: TransitionValues?, endVisibility: Int )` The default implementation of this method does nothing.
`Animator?`	`onDisappear( sceneRoot: ViewGroup, startValues: TransitionValues?, startVisibility: Int, endValues: TransitionValues?, endVisibility: Int )` The default implementation of this method does nothing.
`Unit`	`setMode(mode: Int)` Changes the transition to support appearing and/or disappearing Views, depending on `mode`.

Constants

IN

Added in 1.0.0

const val IN = 1: Int

Fading mode used in Fade to make the transition operate on targets that are appearing. Maybe be combined with OUT to fade both in and out.

OUT

Added in 1.0.0

const val OUT = 2: Int

Fading mode used in Fade to make the transition operate on targets that are disappearing. Maybe be combined with IN to fade both in and out.

Public constructors

Fade

Added in 1.0.0

Fade()

Constructs a Fade transition that will fade targets in and out.

Fade

Added in 1.0.0

Fade(fadingMode: Int)

Constructs a Fade transition that will fade targets in and/or out, according to the value of fadingMode.

Parameters
`fadingMode: Int`	The behavior of this transition, a combination of `IN` and `OUT`.

Fade

Added in 1.0.0

Fade(context: Context, attrs: AttributeSet)

Public functions

captureStartValues

fun captureStartValues(transitionValues: TransitionValues): Unit

Captures the values in the start scene for the properties that this transition monitors. These values are then passed as the startValues structure in a later call to createAnimator. The main concern for an implementation is what the properties are that the transition cares about and what the values are for all of those properties. The start and end values will be compared later during the createAnimator method to determine what, if any, animations, should be run.

Subclasses must implement this method. The method should only be called by the transition system; it is not intended to be called from external classes.

Parameters

Parameters
`transitionValues: TransitionValues`	The holder for any values that the Transition wishes to store. Values are stored in the `values` field of this TransitionValues object and are keyed from a String value. For example, to store a view's rotation value, a transition might call `transitionValues.values.put("appname:transitionname:rotation", view.getRotation())`. The target view will already be stored in the transitionValues structure when this method is called.

transitionValues: TransitionValues

The holder for any values that the Transition wishes to store. Values are stored in the values field of this TransitionValues object and are keyed from a String value. For example, to store a view's rotation value, a transition might call transitionValues.values.put("appname:transitionname:rotation", view.getRotation()). The target view will already be stored in the transitionValues structure when this method is called.

See also
`captureEndValues`
`createAnimator`

isSeekingSupported

fun isSeekingSupported(): Boolean

Returns true if the Transition can be used by controlDelayedTransition. This means that any the state must be ready before any Animator returned by createAnimator has started and if the Animator has ended, it must be able to restore the state when starting in reverse. If a Transition must know when the entire transition has ended, a TransitionListener can be added to getRootTransition and it can listen for onTransitionEnd.

onAppear

fun onAppear(
    sceneRoot: ViewGroup,
    view: View,
    startValues: TransitionValues?,
    endValues: TransitionValues?
): Animator?

The default implementation of this method returns a null Animator. Subclasses should override this method to make targets appear with the desired transition. The method should only be called from onAppear.

Parameters
`sceneRoot: ViewGroup`	The root of the transition hierarchy
`view: View`	The View to make appear. This will be in the target scene's View hierarchy and will be VISIBLE.
`startValues: TransitionValues?`	The target values in the start scene
`endValues: TransitionValues?`	The target values in the end scene

Returns
`Animator?`	An Animator to be started at the appropriate time in the overall transition for this scene change. A null value means no animation should be run.

onDisappear

fun onDisappear(
    sceneRoot: ViewGroup,
    view: View,
    startValues: TransitionValues?,
    endValues: TransitionValues?
): Animator?

The default implementation of this method returns a null Animator. Subclasses should override this method to make targets disappear with the desired transition. The method should only be called from onDisappear.

Parameters
`sceneRoot: ViewGroup`	The root of the transition hierarchy
`view: View`	The View to make disappear. This will be in the target scene's View hierarchy or in an `android.view.ViewGroupOverlay` and will be VISIBLE.
`startValues: TransitionValues?`	The target values in the start scene
`endValues: TransitionValues?`	The target values in the end scene

Returns
`Animator?`	An Animator to be started at the appropriate time in the overall transition for this scene change. A null value means no animation should be run.