Fade


public class Fade
extends Visibility

java.lang.Object
   ↳ android.transition.Transition
     ↳ android.transition.Visibility
       ↳ android.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 View#setVisibility(int) 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 ViewGroupOverlay while fading. If a visible view is changed to be View#GONE or View#INVISIBLE, then the visibility will be changed to View#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 R.styleable.Fade and R.styleable.Transition.

Summary

Inherited XML attributes

Constants

int IN

Fading mode used in Fade(int) to make the transition operate on targets that are appearing.

int OUT

Fading mode used in Fade(int) to make the transition operate on targets that are disappearing.

Inherited constants

Public constructors

Fade()

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

Fade(int fadingMode)

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

Fade(Context context, AttributeSet attrs)

Public methods

void captureStartValues(TransitionValues transitionValues)

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

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

The default implementation of this method returns a null Animator.

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

The default implementation of this method returns a null Animator.

Inherited methods

Constants

IN

Added in API level 19
public static final int IN

Fading mode used in Fade(int) to make the transition operate on targets that are appearing. Maybe be combined with OUT to fade both in and out. Equivalent to Visibility#MODE_IN.

Constant Value: 1 (0x00000001)

OUT

Added in API level 19
public static final int OUT

Fading mode used in Fade(int) to make the transition operate on targets that are disappearing. Maybe be combined with IN to fade both in and out. Equivalent to Visibility#MODE_OUT.

Constant Value: 2 (0x00000002)

Public constructors

Fade

Added in API level 19
public Fade ()

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

Fade

Added in API level 19
public Fade (int fadingMode)

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. Value is either 0 or a combination of Visibility.MODE_IN, Visibility.MODE_OUT, IN, and OUT

Fade

Added in API level 21
public Fade (Context context, 
                AttributeSet attrs)

Parameters
context Context

attrs AttributeSet

Public methods

captureStartValues

Added in API level 19
public void captureStartValues (TransitionValues transitionValues)

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(android.view.ViewGroup, android.transition.TransitionValues, android.transition.TransitionValues). 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(android.view.ViewGroup, android.transition.TransitionValues, android.transition.TransitionValues) 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.

onAppear

Added in API level 21
public Animator onAppear (ViewGroup sceneRoot, 
                View view, 
                TransitionValues startValues, 
                TransitionValues endValues)

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(android.view.ViewGroup, android.transition.TransitionValues, int, android.transition.TransitionValues, int).

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

Added in API level 21
public Animator onDisappear (ViewGroup sceneRoot, 
                View view, 
                TransitionValues startValues, 
                TransitionValues endValues)

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(android.view.ViewGroup, android.transition.TransitionValues, int, android.transition.TransitionValues, int).

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 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.