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MotionLayout rotate image and resetting rotation android

I'm rotating an imageview using MotionLayout.
First click, image rotate clockwise, that's what i want.
But second click, image rotate counterclockwise. I tried some way to reset state of image but it doesn't work.
Can i have a advise???
<MotionScene
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:motion="http://schemas.android.com/apk/res-auto">
<Transition
motion:constraintSetEnd="#+id/end"
motion:constraintSetStart="#id/start"
motion:duration="1500">
<OnClick motion:clickAction="toggle"
motion:targetId="#id/img_reload_cast_dialog"/>
</Transition>
<ConstraintSet android:id="#+id/start">
<Constraint
android:id="#+id/img_reload_cast_dialog"
motion:layout_constraintEnd_toStartOf="#id/img_help_cast_dialog"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="#dimen/_20sdp"
motion:layout_constraintTop_toTopOf="parent" >
<Transform android:rotation="0" />
</Constraint>
</ConstraintSet>
<ConstraintSet android:id="#+id/end">
<Constraint
android:id="#+id/img_reload_cast_dialog"
motion:layout_constraintEnd_toStartOf="#id/img_help_cast_dialog"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="#dimen/_20sdp"
motion:layout_constraintTop_toTopOf="parent" >
<Transform android:rotation="720" />
</Constraint>
</ConstraintSet>
</MotionScene>

I think I figured out what you wanted.
You want a button that goes from rotate the view and essentially stays in start state
There are several ways to do this.
Probably the simplest from your your current XML is to add
motion:autoTransition="jumpToStart"
to you transition.
Alternative is to add another transition from end to start that is auto transition and duration 0.
<Transition
motion:constraintSetEnd="#+id/start"
motion:constraintSetStart="#id/end"
motion:autoTransition="jumpToStart"
//>
see MotionTags video on Transition for an overview
Other approaches are
ViewTransitions
Adding a KeyCycle of rotation with a wave shape sawtooth

Changing height and width of view in keyframes

I need animation which expands a view from height and width of wrap_contents to match constraints, in my case it is to expand as much as parent allows in width but in 50% animation I want that view to first move to center without modifying its height or width.
In first constraint set i have:
<ConstraintSet android:id="#+id/base">
<Constraint android:id="#+id/backgroundView">
<Layout
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_marginEnd="12dp"
android:layout_marginBottom="12dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
<CustomAttribute
app:attributeName="radius"
app:customDimension="30dp" />
</Constraint>
</ConstraintSet>
And the final one is:
<ConstraintSet
android:id="#+id/final"
app:deriveConstraintsFrom="#id/base">
<Constraint android:id="#+id/backgroundView">
<Layout
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginEnd="0dp"
android:layout_marginBottom="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<CustomAttribute
app:attributeName="radius"
app:customDimension="12dp" />
</Constraint>
</ConstraintSet>
My transition is:
<Transition
app:constraintSetEnd="#id/final"
app:constraintSetStart="#id/base"
app:duration="300"
app:motionInterpolator="easeInOut">
<KeyFrameSet>
<KeyPosition
app:framePosition="50"
app:keyPositionType="parentRelative"
app:motionTarget="#id/backgroundView"
app:pathMotionArc="startHorizontal"
app:percentX="0.5"
app:percentY="0.5" />
<KeyAttribute
app:framePosition="50"
app:motionTarget="#id/backgroundView">
<CustomAttribute
app:attributeName="radius"
app:customDimension="30dp" />
</KeyAttribute>
</KeyFrameSet>
</Transition>
With this transition I managed to move the view to center but at the same time view is expanding to match new constraints. How can I keep the view to have width and height of 60dp until frame position goes past 50?

Just add this key position to your keyframe set:
<KeyPosition
app:keyPositionType="deltaRelative"
app:framePosition="50"
app:motionTarget="#id/backgroundView"
app:sizePercent="0" />
By combining keyPositionType="deltaRelative" and sizePercent="0" you define that start size should remain unchanged until this key frame.

How to replicate YouTubes "pull down to exit fullscreen" gesture?

I'm trying to create an app using exoplayer, and I'd like to implement a "pull down to exit fullscreen" gesture just like the youtube app has. The gesture itself seems to be doable using a gesture detector, but i don't have a ideo how to create the "pulling down and shrinking the whole video" effect.
Like this
How can i implement this?

To implement this I think you can use MotionLayout. You can take a look to the documentation here: https://developer.android.com/training/constraint-layout/motionlayout/examples
With MotionLayout you can have a view that can be your fullscreen video or whatever and you can animate it based on an action like the user draggin. It defines the animation in a MotionScene like this:
<MotionScene xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:motion="http://schemas.android.com/apk/res-auto">
<Transition
motion:constraintSetEnd="#+id/end"
motion:constraintSetStart="#+id/start"
motion:duration="1000"
motion:motionInterpolator="linear">
<OnSwipe
motion:dragDirection="dragRight"
motion:touchAnchorId="#id/button"
motion:touchAnchorSide="right" />
</Transition>
<ConstraintSet android:id="#+id/start">
<Constraint
android:id="#id/button"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_marginStart="8dp"
motion:layout_constraintBottom_toBottomOf="parent"
motion:layout_constraintStart_toStartOf="parent"
motion:layout_constraintTop_toTopOf="parent">
<CustomAttribute
motion:attributeName="BackgroundColor"
motion:customColorValue="#D81B60" />
</Constraint>
</ConstraintSet>
<ConstraintSet android:id="#+id/end">
<Constraint
android:id="#id/button"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_marginEnd="8dp"
motion:layout_constraintBottom_toBottomOf="parent"
motion:layout_constraintEnd_toEndOf="parent"
motion:layout_constraintTop_toTopOf="parent">
<CustomAttribute
motion:attributeName="BackgroundColor"
motion:customColorValue="#9999FF" />
</Constraint>
</ConstraintSet>
</MotionScene>
You can see that you can define the action as a new node like the OnSwipe, there you specify the direction and the touch properties. I think the documentation can help expand on all the posibilities, please take a look.

Is it possible to animate groups visibility with MotionLayout?

I'm trying to make an animation with MotionLayout, and I need to hide some elements.
I tested visibility attribute in an individual element and it works, but to make the XML shorter I would like to be able to specify just a group (from the ConstraintLayout helpers) containing all this elements
Something like this
<MotionScene xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<Transition
app:constraintSetStart="#id/start"
app:constraintSetEnd="#id/end"
app:duration="300">
<OnSwipe
app:touchAnchorId="#id/details_group"
app:touchAnchorSide="bottom"
app:dragDirection="dragDown"
/>
</Transition>
<ConstraintSet
android:id="#+id/start">
<Constraint
android:id="#+id/details_group"
android:layout_width="0dp"
android:layout_height="0dp"
android:visibility="gone"
app:constraint_referenced_ids="detail_value_topl,detail_icon_topl,detail_value_topr" />
</ConstraintSet>
<ConstraintSet
android:id="#+id/end">
<Constraint
android:id="#+id/details_group"
android:layout_width="0dp"
android:layout_height="0dp"
android:visibility="visible"
app:constraint_referenced_ids="detail_value_topl,detail_icon_topl,detail_value_topr" />
</ConstraintSet>
</MotionScene>
But it doesn't work, any idea how to make it work ?
Also, I would prefer not to use alpha, since all constraints are set so that when they are gone the container resizes

Rather than declaring the visibility on the Constraint, you should declare the visibility as a custom attribute. So for your first constraint try this:
<Constraint
android:id="#+id/details_group"
android:layout_width="0dp"
android:layout_height="0dp"
app:constraint_referenced_ids="detail_value_topl,detail_icon_topl,detail_value_topr">
<CustomAttribute
motion:attributeName="visibility"
motion:customIntegerValue="8" />
</Constraint>
and for your second constraint try this
<Constraint
android:id="#+id/details_group"
android:layout_width="0dp"
android:layout_height="0dp"
app:constraint_referenced_ids="detail_value_topl,detail_icon_topl,detail_value_topr">
<CustomAttribute
motion:attributeName="visibility"
motion:customIntegerValue="0" />
</Constraint>
By declaring the visibility as a custom attribute, that should help the motion layout properly interpolate between visibility values. It's a little unintuitive which int value is which visibility but they are defined as follows
Visible = 0
Invisible = 4
Gone = 8

Problem with multiple Transitions in Android MotionLayout

I'm playing around with the MotionLayout in Android. I'm using the alpha 2 version.
'com.android.support.constraint:constraint-layout:2.0.0-alpha2'
I want to react to two different button clicks and trigger an animation for each of them. My current approach is to set two Transitions in the MotionScene with an OnClick trigger in each one.
The problem is that only the first transition seems to be found. For the second one just nothing happens. Am I doing something wrong or can you just set one transition per MotionScene? If that's the case ist there a different solution to the problem?
Here are the important parts of my Motion Scene
<MotionScene xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:motion="http://schemas.android.com/apk/res-auto">
<Transition
motion:constraintSetStart="#id/startHome"
motion:constraintSetEnd="#id/endHome"
motion:duration="300">
<OnClick
motion:mode="toggle"
motion:target="#+id/imageView_bottom_home" />
</Transition>
<Transition
motion:constraintSetStart="#id/startSearch"
motion:constraintSetEnd="#id/endSearch"
motion:duration="300">
<OnClick
motion:mode="toggle"
motion:target="#+id/imageView_bottom_search" />
</Transition>
<ConstraintSet android:id="#+id/startSearch">
<Constraint
android:id="#id/imageView_bottom_search"
...startConstraints... />
</ConstraintSet>
<ConstraintSet android:id="#+id/endSearch">
<Constraint
android:id="#id/imageView_bottom_search"
...endConstraints... />
</ConstraintSet>
<ConstraintSet android:id="#+id/startHome">
<Constraint
android:id="#id/imageView_bottom_home"
...startConstraints... />
</ConstraintSet>
<ConstraintSet android:id="#+id/endHome">
<Constraint
android:id="#id/imageView_bottom_home"
...endConstraints... />
</ConstraintSet>
Any help appreciated.
Best regards

I had the same problem. The solution I found was to select which one transitions:
(in java code)...
MotionLayout motionConteiner = findViewById(R.id.motion_container);
button1.setOnClickListener((v) -> {
motionConteiner.setTransition(R.id.start1, R.id.end1);
motionConteiner.transitionToEnd();//
});
button2.setOnClickListener((v) -> {
motionConteiner.setTransition(R.id.start2, R.id.end2);
motionConteiner.transitionToEnd();//
});

A more kotlin'y answer:
with(view as MotionLayout) {
setTransition(R.id.startState, R.id.endState)
transitionToEnd()
}

Multiple transitions are supported.
In the code you shared, you have 4 constraint sets, start_home -> end_home, start_search -> end_search. Instead, have only 3 sets, with one being the base state like, start -> end_home and start -> end_search. The 'start' here represents the base state of the screen
This happens because, say you did the home action first and then you did the search action, then the search is not going to work because the starting criteria (start_search) is not going to match the start_home or end_home (which got applied last)

I think aba is right. I am also having problem adding multiple transitions to a single scene file. Theoretically, MotionLayout should support this because every transition will have a separate trigger (often as click or swipe). Maybe this is a bug with MotionLayout that needs to be fixed.
Out of my experience, only the first transition that is encountered in the scene file is cared for.
So, currently, I don't think there is a way to support more than one transition in a layout description (scene). To put it more specifically, all motion needs to be started once with the same trigger.

Seems to me that MotionLayout only supports one Transition, when you add a second Transition to the MotionScene file the second Transition appears to be ignored. You can however have multiple MotionLayouts in your layout and create a MotionScene for each MotionLayout. This will also keep the MotionScene file cleaner and allow for easier maintenance.
In your layout file, you'll need a Parent layout that can contain multiple MotionLayout files.
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<data>
...
</data>
<!-- [databinding] {"msg":"Only one layout element with 1 view child is allowed. So a Parent Layout is required for Multiple motion layouts. -->
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.motion.widget.MotionLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layoutDescription="#xml/motion_scene_01"
tools:context=".menu.contextual.FragmentContextualOne"
tools:showPath="true">
<Button
android:id="#+id/btn_one"
android:layout_width="64dp"
android:layout_height="64dp"
tools:layout_editor_absoluteX="8dp"
tools:layout_editor_absoluteY="310dp" />
</androidx.constraintlayout.motion.widget.MotionLayout>
<androidx.constraintlayout.motion.widget.MotionLayout
android:id="#+id/m2"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layoutDescription="#xml/motion_scene_02">
<Button
android:id="#+id/btn_two"
android:layout_width="64dp"
android:layout_height="64dp"
tools:layout_editor_absoluteX="8dp"
tools:layout_editor_absoluteY="500dp" />
</androidx.constraintlayout.motion.widget.MotionLayout>
</FrameLayout>
</layout>
Motion Scene One.
<?xml version="1.0" encoding="utf-8"?>
<MotionScene xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:motion="http://schemas.android.com/apk/res-auto">
<Transition
android:id="#+id/transition_sine_wave"
motion:constraintSetStart="#+id/wave_start"
motion:constraintSetEnd="#+id/wave_end"
motion:duration="2000"
motion:motionInterpolator="linear">
<OnClick
motion:touchAnchorId="#+id/btn_one"
motion:touchAnchorSide="right"
motion:targetId="#+id/btn_one"/>
</Transition>
<ConstraintSet android:id="#+id/wave_start">
<Constraint
android:id="#+id/btn_one"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_marginStart="8dp"
motion:layout_constraintBottom_toBottomOf="parent"
motion:layout_constraintTop_toTopOf="parent"
motion:layout_constraintStart_toStartOf="parent"/>
</ConstraintSet>
<ConstraintSet android:id="#+id/wave_end">
<Constraint
android:id="#+id/btn_one"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_marginEnd="8dp"
motion:layout_constraintBottom_toBottomOf="parent"
motion:layout_constraintEnd_toEndOf="parent"
motion:layout_constraintTop_toTopOf="parent" />
</ConstraintSet>
</MotionScene>
Motion Scene Two
<?xml version="1.0" encoding="utf-8"?>
<MotionScene xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:motion="http://schemas.android.com/apk/res-auto">
<Transition
android:id="#+id/transition_straight"
motion:constraintSetEnd="#+id/right_end"
motion:constraintSetStart="#+id/left_start"
motion:duration="2000"
motion:motionInterpolator="linear" >
<OnClick
motion:targetId="#+id/btn_two"
motion:clickAction="toggle"/>
</Transition>
<ConstraintSet android:id="#+id/left_start">
<Constraint
android:id="#+id/btn_two"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_marginStart="8dp"
android:layout_marginBottom="100dp"
motion:layout_constraintBottom_toBottomOf="parent"
motion:layout_constraintStart_toStartOf="parent" />
</ConstraintSet>
<ConstraintSet android:id="#+id/right_end">
<Constraint
android:id="#+id/btn_two"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_marginEnd="8dp"
motion:layout_constraintBottom_toBottomOf="parent"
motion:layout_constraintEnd_toEndOf="parent" />
</ConstraintSet>
</MotionScene>
This is the only XML solution I could come up with.