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Advanced & Practical
MotionLayout
Jason Pearson @kaeawc
bit.ly/advanced-motionlayout-talk
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Agenda
• Quick Introduction
• Provide answers to two questions:
- What can MotionLayout do?
- Why is this useful to you & your team?
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–Jinyan Cao @ Robinhood
May 22, 2017
"ConstraintLayout seems to be the hot new thing
nowadays. Flattening your view hierarchy, improving
performance, supporting arbitrary bounding rules..."
"... one other benefit of ConstraintLayout that most
people are unaware of and the official
documentation curiously doesn’t mention anything
about: performing cool animations on your
ConstraintLayout views with very little code."
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–Jinyan Cao @ Robinhood
May 22, 2017
"ConstraintLayout seems to be the hot new thing
nowadays. Flattening your view hierarchy, improving
performance, supporting arbitrary bounding rules..."
"... one other benefit of ConstraintLayout that most
people are unaware of and the official
documentation curiously doesn’t mention anything
about: performing cool animations on your
ConstraintLayout views with very little code."
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ConstraintLayout Animations
@layout/activity_main
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ConstraintLayout Animations
@layout/activity_main
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ConstraintLayout Animations
@layout/activity_main
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ConstraintLayout Animations
@layout/activity_main
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ConstraintLayout Animations
@layout/activity_main
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@layout/activity_main
MainActivity.kt
fun onClicked() {
ConstraintSet().apply {
constrainWidth(square.id, 100.dp())
constrainHeight(square.id, 100.dp())
connect(square.id, START, 0, START, 0)
connect(square.id, END, 0, END, 0)
connect(square.id, BOTTOM, 0, BOTTOM, 0)
applyTo(root_view)
}
}
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@layout/activity_main
MainActivity.kt
fun onClicked() {
TransitionManager.beginDelayedTransition(root_view)
ConstraintSet().apply {
constrainWidth(square.id, 100.dp())
constrainHeight(square.id, 100.dp())
connect(square.id, START, 0, START, 0)
connect(square.id, END, 0, END, 0)
connect(square.id, BOTTOM, 0, BOTTOM, 0)
applyTo(root_view)
}
}
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@layout/activity_main
MainActivity.kt
fun onClicked() {
TransitionManager.beginDelayedTransition(root_view)
ConstraintSet().apply {
constrainWidth(square.id, 100.dp())
constrainHeight(square.id, 100.dp())
connect(square.id, START, 0, START, 0)
connect(square.id, END, 0, END, 0)
connect(square.id, BOTTOM, 0, BOTTOM, 0)
applyTo(root_view)
}
}
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@layout/activity_main
MainActivity.kt
fun onClicked() {
TransitionManager.beginDelayedTransition(root_view)
ConstraintSet().apply {
load(baseContext, R.layout.keyframe_two)
applyTo(root_view)
}
}
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What is MotionLayout?
• Extended class of ConstraintLayout
• Library of helper functions to coordinate animation
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@layout/activity_main
What is MotionLayout?
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@layout/activity_main
What is MotionLayout?
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@layout/activity_main
What is MotionLayout?
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What is MotionLayout?
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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Constraints
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Derived ConstraintSets
• Introduced in ConstraintLayout 2.0 alpha 5
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Derived ConstraintSets
@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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@xml/motion_scene
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Constraints
• ConstraintLayout bounds can position or resize child
views.
• There are other Sub Elements that can be applied
within a Constraint.
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@xml/motion_scene
Constraints - Sub Elements
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@xml/motion_scene
Constraints - Sub Elements
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@xml/motion_scene
Constraints - Path Motion Arc
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@xml/motion_scene
Constraints - Path Motion Arc
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@xml/motion_scene
Constraints - Path Motion Arc
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Constraints - Progress
• PropertySet sub element allows a parent to pass its
progress to a child MotionLayout
• app:motionProgress
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@xml/header_scene
Constraints - Progress
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@xml/header_scene
Constraints - Progress
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@xml/header_scene
Constraints - Progress
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@xml/header_scene
@xml/scrolling_scene
Constraints - Progress
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@xml/header_scene
@xml/scrolling_scene
Constraints - Progress
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@xml/header_scene
@xml/scrolling_scene
Constraints - Progress
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@xml/header_scene
@xml/scrolling_scene
Constraints - Progress
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@xml/header_scene
@xml/scrolling_scene
Constraints - Progress
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@xml/header_scene
@xml/scrolling_scene
Constraints - Progress
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@xml/header_scene
@xml/scrolling_scene
Constraints - Progress
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@xml/header_scene
@xml/scrolling_scene
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@xml/header_scene
@xml/scrolling_scene
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@xml/header_scene
@xml/scrolling_scene
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@xml/header_scene
@xml/scrolling_scene
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@xml/header_scene
@xml/scrolling_scene
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@xml/header_scene
@xml/scrolling_scene
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Constraints - Changing Programmatically
• MotionLayout is just an extension of ConstraintLayout
• After making changes to a ConstraintSet we must call
MotionLayout.updateState(stateId, constraintSet)
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Constraints - Changing Programmatically
MainActivity.kt
constraintSet.constrainWidth(viewId, boundaries.width)
constraintSet.constrainHeight(viewId, boundaries.height)
constraintSet.connect(viewId, TOP, R.id.boundaries, TOP, 0)
constraintSet.connect(viewId, START, R.id.boundaries, START, 0)
constraintSet.connect(viewId, END, R.id.boundaries, END, 0)
constraintSet.connect(viewId, BOTTOM, R.id.boundaries, BOTTOM, 0)
constraintSet.setElevation(view.id, 1f)
motion_layout.updateState(R.id.zoomed_in, constraintSet)
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MainActivity.kt
constraintSet.constrainWidth(viewId, boundaries.width)
constraintSet.constrainHeight(viewId, boundaries.height)
constraintSet.connect(viewId, TOP, R.id.boundaries, TOP, 0)
constraintSet.connect(viewId, START, R.id.boundaries, START, 0)
constraintSet.connect(viewId, END, R.id.boundaries, END, 0)
constraintSet.connect(viewId, BOTTOM, R.id.boundaries, BOTTOM, 0)
constraintSet.setElevation(view.id, 1f)
motion_layout.updateState(R.id.zoomed_in, constraintSet)
@xml/motion_scene
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MainActivity.kt
constraintSet.constrainWidth(viewId, boundaries.width)
constraintSet.constrainHeight(viewId, boundaries.height)
constraintSet.connect(viewId, TOP, R.id.boundaries, TOP, 0)
constraintSet.connect(viewId, START, R.id.boundaries, START, 0)
constraintSet.connect(viewId, END, R.id.boundaries, END, 0)
constraintSet.connect(viewId, BOTTOM, R.id.boundaries, BOTTOM, 0)
constraintSet.setElevation(view.id, 1f)
motion_layout.updateState(R.id.zoomed_in, constraintSet)
@xml/motion_scene
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Constraints - Limitations
• Some problems cannot be solved with derived
Constraints.
• Creating a very large number of ConstraintSets and
Transitions is infeasible.
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Constraints - Limitations
N!/2 States
Each requires a handwritten ConstraintSet
This 2x2 board has 12 states
A 3x3 board would have 181440 states
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Constraints - Limitations
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Transitions
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autoTransition property
• Can specify whether to animate or jump to the start or
end of a transition
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autoTransition property
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@xml/motion_scene
autoTransition property
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@xml/motion_scene
KeyFrameSet in Transitions
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@xml/motion_scene
KeyFrameSet in Transitions
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@xml/motion_scene
KeyFrameSet in Transitions
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@xml/motion_scene
KeyFrameSet in Transitions
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@xml/motion_scene
KeyFrameSet in Transitions
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@xml/motion_scene
app:motionInterpolator="easeOut"
Interpolators in Transitions
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@xml/motion_scene
app:motionInterpolator="cubic(0.4,0,1,1)"
Interpolators in Transitions
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@xml/motion_scene
app:motionInterpolator="cubic(0.4,0,1,1)"
https://cubic-bezier.com/#.42,0,1,1
Interpolators in Transitions
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@xml/motion_scene
app:motionInterpolator="cubic(0.4,0,1,1)"
https://cubic-bezier.com/#.42,0,1,1
Interpolators in Transitions
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Changing Transitions on the fly
• Only current option to turn on and off
autoTransition is via reflection.
• I've opened an issue on
ConstraintLayout requesting access to
programmatically modify this flag.
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Changing Transitions on the fly
• Only current option to turn on and off
autoTransition is via reflection.
• I've opened an issue on
ConstraintLayout requesting access to
programmatically modify this flag.
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Changing Transitions on the fly
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MotionLayout
+
RecyclerView
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MotionLayout & RecyclerView
• ConstraintLayout team has demoed their own
placeholder implementation that uses
RecyclerView.Adapter, but it's not yet available.
• I've opted to programmatically manipulate
ConstraintSets & Transitions to achieve a similar
placeholder behavior.
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@xml/placeholder_scene
MotionLayout & RecyclerView
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@xml/placeholder_scene
MotionLayout & RecyclerView
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@xml/placeholder_scene
MotionLayout & RecyclerView
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@xml/placeholder_scene
MotionLayout & RecyclerView
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@xml/placeholder_scene
MotionLayout & RecyclerView
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@xml/placeholder_scene
MotionLayout & RecyclerView
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app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintBottom_toBottomOf="parent" >
MotionLayout & RecyclerView
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app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintBottom_toBottomOf="parent" >
MotionLayout & RecyclerView
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motion_layout?.apply {
val cs = getConstraintSet(R.id.scrolling)
cs?.constrainWidth(placeholder.id, MATCH_PARENT)
cs?.constrainHeight(placeholder.id, WRAP_CONTENT)
if (topOffset > 0) {
cs?.setMargin(placeholder.id, TOP, placeholderTop)
cs?.setMargin(placeholder.id, BOTTOM, 0)
cs?.setVerticalBias(placeholder.id, 0f)
} else {
cs?.setMargin(placeholder.id, BOTTOM, placeholderBottom)
cs?.setMargin(placeholder.id, TOP, 0)
cs?.setVerticalBias(placeholder.id, 1f)
}
cs?.connect(placeholder.id, START, parentId, START, startMargin)
cs?.connect(placeholder.id, END, parentId, END, startMargin)
updateState(R.id.scrolling, cs)
setTransition(R.id.scrolling, R.id.selected)
placeholder?.isVisible = true
transitionToEnd()
}
MotionLayout & RecyclerView
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val cs = getConstraintSet(R.id.scrolling)
cs?.constrainWidth(placeholder.id, MATCH_PARENT)
cs?.constrainHeight(placeholder.id, WRAP_CONTENT)
if (topOffset > 0) {
cs?.setMargin(placeholder.id, TOP, placeholderTop)
cs?.setMargin(placeholder.id, BOTTOM, 0)
cs?.setVerticalBias(placeholder.id, 0f)
} else {
cs?.setMargin(placeholder.id, BOTTOM, placeholderBottom)
cs?.setMargin(placeholder.id, TOP, 0)
cs?.setVerticalBias(placeholder.id, 1f)
}
cs?.connect(placeholder.id, START, parentId, START, startMargin)
cs?.connect(placeholder.id, END, parentId, END, startMargin)
updateState(R.id.scrolling, cs)
setTransition(R.id.scrolling, R.id.selected)
placeholder?.isVisible = true
transitionToEnd()
MotionLayout & RecyclerView
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val cs = getConstraintSet(R.id.scrolling)
cs?.constrainWidth(placeholder.id, MATCH_PARENT)
cs?.constrainHeight(placeholder.id, WRAP_CONTENT)
if (topOffset > 0) {
cs?.setMargin(placeholder.id, TOP, placeholderTop)
cs?.setMargin(placeholder.id, BOTTOM, 0)
cs?.setVerticalBias(placeholder.id, 0f)
} else {
cs?.setMargin(placeholder.id, BOTTOM, placeholderBottom)
cs?.setMargin(placeholder.id, TOP, 0)
cs?.setVerticalBias(placeholder.id, 1f)
}
cs?.connect(placeholder.id, START, parentId, START, startMargin)
cs?.connect(placeholder.id, END, parentId, END, startMargin)
updateState(R.id.scrolling, cs)
setTransition(R.id.scrolling, R.id.selected)
placeholder?.isVisible = true
transitionToEnd()
MotionLayout & RecyclerView
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val cs = getConstraintSet(R.id.scrolling)
cs?.constrainWidth(placeholder.id, MATCH_PARENT)
cs?.constrainHeight(placeholder.id, WRAP_CONTENT)
if (topOffset > 0) {
cs?.setMargin(placeholder.id, TOP, placeholderTop)
cs?.setMargin(placeholder.id, BOTTOM, 0)
cs?.setVerticalBias(placeholder.id, 0f)
} else {
cs?.setMargin(placeholder.id, BOTTOM, placeholderBottom)
cs?.setMargin(placeholder.id, TOP, 0)
cs?.setVerticalBias(placeholder.id, 1f)
}
cs?.connect(placeholder.id, START, parentId, START, startMargin)
cs?.connect(placeholder.id, END, parentId, END, startMargin)
updateState(R.id.scrolling, cs)
setTransition(R.id.scrolling, R.id.selected)
placeholder?.isVisible = true
transitionToEnd()
MotionLayout & RecyclerView
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val cs = getConstraintSet(R.id.scrolling)
cs?.constrainWidth(placeholder.id, MATCH_PARENT)
cs?.constrainHeight(placeholder.id, WRAP_CONTENT)
if (topOffset > 0) {
cs?.setMargin(placeholder.id, TOP, placeholderTop)
cs?.setMargin(placeholder.id, BOTTOM, 0)
cs?.setVerticalBias(placeholder.id, 0f)
} else {
cs?.setMargin(placeholder.id, BOTTOM, placeholderBottom)
cs?.setMargin(placeholder.id, TOP, 0)
cs?.setVerticalBias(placeholder.id, 1f)
}
cs?.connect(placeholder.id, START, parentId, START, startMargin)
cs?.connect(placeholder.id, END, parentId, END, startMargin)
updateState(R.id.scrolling, cs)
setTransition(R.id.scrolling, R.id.selected)
placeholder?.isVisible = true
transitionToEnd()
MotionLayout & RecyclerView
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cs?.constrainHeight(placeholder.id, WRAP_CONTENT)
if (topOffset > 0) {
cs?.setMargin(placeholder.id, TOP, placeholderTop)
cs?.setMargin(placeholder.id, BOTTOM, 0)
cs?.setVerticalBias(placeholder.id, 0f)
} else {
cs?.setMargin(placeholder.id, BOTTOM, placeholderBottom)
cs?.setMargin(placeholder.id, TOP, 0)
cs?.setVerticalBias(placeholder.id, 1f)
}
cs?.connect(placeholder.id, START, parentId, START, startMargin)
cs?.connect(placeholder.id, END, parentId, END, startMargin)
updateState(R.id.scrolling, cs)
setTransition(R.id.scrolling, R.id.selected)
placeholder?.isVisible = true
transitionToEnd()
MotionLayout & RecyclerView
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cs?.setVerticalBias(placeholder.id, 0f)
} else {
cs?.setMargin(placeholder.id, BOTTOM, placeholderBottom)
cs?.setMargin(placeholder.id, TOP, 0)
cs?.setVerticalBias(placeholder.id, 1f)
}
cs?.connect(placeholder.id, START, parentId, START, startMargin)
cs?.connect(placeholder.id, END, parentId, END, startMargin)
updateState(R.id.scrolling, cs)
setTransition(R.id.scrolling, R.id.selected)
placeholder?.isVisible = true
transitionToEnd()
MotionLayout & RecyclerView
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MotionLayout & RecyclerView
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Summary
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Why You Should Try MotionLayout
• Reduces context switching
• Makes some hard animations much easier
• Allows us to make animations reentrant, continuous, &
smooth
- Watch Nick Butcher's I/O 2019 Motional Intelligence
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Challenges in using MotionLayout
• It’s still in beta
• Lack of learning materials
• Debugging is a bit of trial and error - waiting for highly
anticipated MotionEditor
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Can we use it with Jetpack Compose? NOT YET
Should we ever use Coordinator Layout again? NO
Physics based Transitions? NOT YET
Is Hinge hiring? YES
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Questions?
Is Hinge hiring? YES
bit.ly/advanced-motionlayout-talk