MotionLayout not resized when animating

Question

I have this view:

<androidx.constraintlayout.motion.widget.MotionLayout
                    android:id="@+id/expandableModes"
                    android:layout_width="200dp"
                    android:layout_height="200dp"
                    android:paddingBottom="5dp"
                    app:layoutDescription="@xml/journey_motion"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintStart_toStartOf="@id/guidelineLeft"
                    app:layout_constraintTop_toBottomOf="@id/travelModeText">
    ....
    </androidx.constraintlayout.motion.widget.MotionLayout>

And this motion layout:

<?xml version="1.0" encoding="utf-8"?>
<MotionScene xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <Transition
        app:constraintSetEnd="@id/endExpand"
        app:constraintSetStart="@id/startExpand"
        app:duration="1000" />
    <ConstraintSet android:id="@+id/startExpand">
        <Constraint
            android:id="@id/expandableModes"
            android:layout_width="200dp"
            android:layout_height="200dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="@id/guidelineLeft"
            app:layout_constraintTop_toBottomOf="@id/travelModeText" />
    </ConstraintSet>
    <ConstraintSet android:id="@+id/endExpand">
        <Constraint
            android:id="@id/expandableModes"
            android:layout_width="10dp"
            android:layout_height="10dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="@id/guidelineLeft"
            app:layout_constraintTop_toBottomOf="@id/travelModeText" />
    </ConstraintSet>
</MotionScene>

I execute it by code:

binding.expandableModes.transitionToEnd {
                        print("")
                    }

My animation is played but my view is not resized, what did I missed ?

Answer 1

You are trying to animate the motion layout itself. You can only animate direct children as described here: https://developer.android.com/training/constraint-layout/motionlayout

You need to create a children of the view and animate this.