Specifies view attributes at a specific moment during the motion sequence. You
can use <KeyAttribute> to set the view's standard attributes.
Suppose a view's opacity (android:alpha) is set to 0 in the initial
<ConstraintSet> and 1 in the final <ConstraintSet>. By default, this makes
the view linearly fade in for the entire motion sequence. If you want the view
to remain invisible for 80% of the motion sequence and then fade in quickly, add
a <KeyAttribute> node with the motion:framePosition attribute set to 80 and
the android:alpha attribute set to 0.
Syntax
<KeyAttribute motion:motionTarget="@id/targetPath" motion:framePosition="percentage" [ attribute = value ] />
Attributes
motion:motionTarget- View whose attributes are controlled by this
<KeyAttribute>. motion:framePosition- Integer from 1 to 99 specifying when in the motion sequence the view has the
attributes specified by this
<KeyAttribute>. For example, ifframePositionis 25, then the view has the specified attributes one-quarter of the way through the motion sequence.
You can set the following view attributes. For more information about these
attributes, see the View reference page.
android:alphaandroid:elevationandroid:rotationandroid:rotationXandroid:rotationYandroid:scaleXandroid:scaleYandroid:translationXandroid:translationYandroid:translationZandroid:visibilitytransitionPathRotate