Root element of a motion scene file. The `<MotionScene>` contains one or more
[`<Transition>`](https://developer.android.com/training/constraint-layout/motionlayout/ref/transition)
elements, each of which defines the start and end state of a motion sequence and
the transition between the two.

## Syntax

```xml
<MotionScene xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android">
    ...
</MotionScene>
```

## Must contain

`<Transition>`
:   Specifies the motion sequence to perform. If the `<MotionScene>` contains
    multiple `<Transition>` elements, the `MotionLayout` chooses the most
    appropriate `<Transition>` based on the user's interaction. For example, a
    `<MotionScene>` might have four `<Transition>` children, each with an
    [`<OnSwipe>`](https://developer.android.com/training/constraint-layout/motionlayout/ref/onswipe) for a user
    swipe in a different direction. When the user swipes on the screen, the
    `MotionLayout` uses the appropriate `<Transition>` for a swipe in that
    direction.

## Can contain

[`<ConstraintSet>`](https://developer.android.com/training/constraint-layout/motionlayout/ref/constraintset)
:   Specifies a beginning or ending state for one or more of the `<Transition>`
    nodes. The `<MotionLayout>` is not permitted to have `<ConstraintSet>`
    children, since the `<Transition>` can point to XML layouts instead of
    pointing to constraint sets.

## Attributes

`defaultDuration`
:   Default duration for all transitions in milliseconds. The default duration is
    used for motion sequences that don't specify their own duration. For example,
    if you set `defaultDuration="300"`, all motion sequences default to 300
    milliseconds in length if they don't explicitly specify their own duration.