ChangeTransform

class ChangeTransform : Transition


This Transition captures scale and rotation for Views before and after the scene change and animates those changes during the transition. A change in parent is handled as well by capturing the transforms from the parent before and after the scene change and animating those during the transition.

Summary

Public constructors

ChangeTransform(context: Context, attrs: AttributeSet)

Public functions

Unit

Captures the values in the end scene for the properties that this transition monitors.

Unit

Captures the values in the start 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.

Boolean

Returns whether parent changes will be tracked by the ChangeTransform.

Boolean

Returns whether changes to parent should use an overlay or not.

Array<String!>

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.

Unit
setReparent(reparent: Boolean)

Sets whether parent changes will be tracked by the ChangeTransform.

Unit
setReparentWithOverlay(reparentWithOverlay: Boolean)

Sets whether changes to parent should use an overlay or not.

Inherited Constants

From androidx.transition.Transition
const Int

With setMatchOrder, chooses to match by getId.

const Int

With setMatchOrder, chooses to match by View instance.

const Int

With setMatchOrder, chooses to match by the android.widget.Adapter item id.

const Int

With setMatchOrder, chooses to match by getTransitionName.

Inherited functions

From androidx.transition.Transition
Transition

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
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

Returns the duration set on this transition.

Rect?

Returns the epicenter as specified by the android.transition.Transition.EpicenterCallback or null if no callback exists.

Transition.EpicenterCallback?

Returns the callback used to find the epicenter of the Transition.

TimeInterpolator?

Returns the interpolator set on this transition.

String

Returns the name of this Transition.

PathMotion

Returns the algorithm object used to interpolate along two dimensions.

TransitionPropagation?

Returns the android.transition.TransitionPropagation used to calculate Animator start delays.

Transition

If this Transition is not part of a TransitionSet, this is returned.

Long

Returns the startDelay set on this transition.

(Mutable)List<Int!>

Returns the array of target IDs that this transition limits itself to tracking and animating.

(Mutable)List<String!>?

Returns the list of target transitionNames that this transition limits itself to tracking and animating.

(Mutable)List<Class<Any!>!>?

Returns the list of target transitionNames that this transition limits itself to tracking and animating.

(Mutable)List<View!>

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.

Boolean

Returns true if the Transition can be used by controlDelayedTransition.

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.

Transition

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

Sets the callback to use to find the epicenter of a Transition.

Transition

Sets the interpolator of this transition.

Unit

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

Public constructors

ChangeTransform

Added in 1.0.0
ChangeTransform()

ChangeTransform

Added in 1.0.0
ChangeTransform(context: Context, attrs: AttributeSet)

Public functions

captureEndValues

Added in 1.5.0-alpha06
fun captureEndValues(transitionValues: TransitionValues): Unit

Captures the values in the end scene for the properties that this transition monitors. These values are then passed as the endValues 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
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.

captureStartValues

Added in 1.5.0-alpha06
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
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.

createAnimator

fun createAnimator(
    sceneRoot: ViewGroup,
    startValues: TransitionValues?,
    endValues: TransitionValues?
): Animator?

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

This method is called by the transition's parent (all the way up to the topmost Transition in the hierarchy) with the sceneRoot and start/end values that the transition may need to set up initial target values and construct an appropriate animation. For example, if an overall Transition is a TransitionSet consisting of several child transitions in sequence, then some of the child transitions may want to set initial values on target views prior to the overall Transition commencing, to put them in an appropriate state for the delay between that start and the child Transition start time. For example, a transition that fades an item in may wish to set the starting alpha value to 0, to avoid it blinking in prior to the transition actually starting the animation. This is necessary because the scene change that triggers the Transition will automatically set the end-scene on all target views, so a Transition that wants to animate from a different value should set that value prior to returning from this method.

Additionally, a Transition can perform logic to determine whether the transition needs to run on the given target and start/end values. For example, a transition that resizes objects on the screen may wish to avoid running for views which are not present in either the start or end scenes.

If there is an animator created and returned from this method, the transition mechanism will apply any applicable duration, startDelay, and interpolator to that animation and start it. A return value of null indicates that no animation should run. The default implementation returns null.

The method is called for every applicable target object, which is stored in the view field.

Parameters
sceneRoot: ViewGroup

The root of the transition hierarchy.

startValues: TransitionValues?

The values for a specific target in the start scene.

endValues: TransitionValues?

The values for the target in the end scene.

Returns
Animator?

A 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.

getReparent

Added in 1.0.0
fun getReparent(): Boolean

Returns whether parent changes will be tracked by the ChangeTransform. If parent changes are tracked, then the transform will adjust to the transforms of the different parents. If they aren't tracked, only the transforms of the transitioning view will be tracked. Default is true.

Returns
Boolean

whether parent changes will be tracked by the ChangeTransform.

getReparentWithOverlay

Added in 1.0.0
fun getReparentWithOverlay(): Boolean

Returns whether changes to parent should use an overlay or not. When the parent change doesn't use an overlay, it affects the transforms of the child. The default value is true.

Note: when Overlays are not used when a parent changes, a view can be clipped when it moves outside the bounds of its parent. Setting setClipChildren and setClipToPadding can help. Also, when Overlays are not used and the parent is animating its location, the position of the child view will be relative to its parent's final position, so it may appear to "jump" at the beginning.

Returns
Boolean

true when a changed parent should execute the transition inside the scene root's overlay or false if a parent change only affects the transform of the transitioning view.

getTransitionProperties

fun getTransitionProperties(): Array<String!>

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. When any transition is started on a given scene root, all transitions currently running on that same scene root are checked to see whether the properties on which they based their animations agree with the end values of the same properties in the new transition. If the end values are not equal, then the old animation is canceled since the new transition will start a new animation to these new values. If the values are equal, the old animation is allowed to continue and no new animation is started for that transition.

A transition does not need to override this method. However, not doing so will mean that the cancellation logic outlined in the previous paragraph will be skipped for that transition, possibly leading to artifacts as old transitions and new transitions on the same targets run in parallel, animating views toward potentially different end values.

Returns
Array<String!>

An array of property names as described in the class documentation for TransitionValues. The default implementation returns null.

setReparent

Added in 1.0.0
fun setReparent(reparent: Boolean): Unit

Sets whether parent changes will be tracked by the ChangeTransform. If parent changes are tracked, then the transform will adjust to the transforms of the different parents. If they aren't tracked, only the transforms of the transitioning view will be tracked. Default is true.

Parameters
reparent: Boolean

Set to true to track parent changes or false to only track changes of the transitioning view without considering the parent change.

setReparentWithOverlay

Added in 1.0.0
fun setReparentWithOverlay(reparentWithOverlay: Boolean): Unit

Sets whether changes to parent should use an overlay or not. When the parent change doesn't use an overlay, it affects the transforms of the child. The default value is true.

Note: when Overlays are not used when a parent changes, a view can be clipped when it moves outside the bounds of its parent. Setting setClipChildren and setClipToPadding can help. Also, when Overlays are not used and the parent is animating its location, the position of the child view will be relative to its parent's final position, so it may appear to "jump" at the beginning.

Parameters
reparentWithOverlay: Boolean

true when a changed parent should execute the transition inside the scene root's overlay or falseif a parent change only affects the transform of the transitioning view.