# Class Index

# Class Index

| The`android.support`Constraint Layout packages are no longer maintained. They have been superseded by the corresponding[androidx.\*](https://developer.android.com/jetpack/androidx/migrate)packages.

These are the API classes. See all[API packages](https://developer.android.com/reference/android/support/constraint/packages).

## A

|----------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------|
| [Animatable](https://developer.android.com/reference/android/support/constraint/motion/Animatable) | A helper interface allowing MotionLayout to directly drive custom views |

## B

|---------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------|
| [Barrier](https://developer.android.com/reference/android/support/constraint/Barrier) | **Added in 1.1** A Barrier references multiple widgets as input, and creates a virtual guideline based on the most extreme widget on the specified side. |

## C

|-----------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [ConstraintLayout](https://developer.android.com/reference/android/support/constraint/ConstraintLayout)                           | A`ConstraintLayout`is a[android.view.ViewGroup](https://developer.android.com/reference/android/view/ViewGroup/package-summary)which allows you to position and size widgets in a flexible way.                 |
| [ConstraintLayout.LayoutParams](https://developer.android.com/reference/android/support/constraint/ConstraintLayout.LayoutParams) | This class contains the different attributes specifying how a view want to be laid out inside a[ConstraintLayout](https://developer.android.com/reference/android/support/constraint/ConstraintLayout).         |
| [ConstraintProperties](https://developer.android.com/reference/android/support/constraint/ConstraintProperties)                   | **Added in 2.0** ConstraintProperties provides an easy to use api to update the layout params of[ConstraintLayout](https://developer.android.com/reference/android/support/constraint/ConstraintLayout)children |
| [ConstraintsChangedListener](https://developer.android.com/reference/android/support/constraint/ConstraintsChangedListener)       | **Added in 2.0** Callbacks on state change                                                                                                                                                                      |
| [ConstraintSet](https://developer.android.com/reference/android/support/constraint/ConstraintSet)                                 | This class allows you to define programmatically a set of constraints to be used with[ConstraintLayout](https://developer.android.com/reference/android/support/constraint/ConstraintLayout).                   |

## F

|----------------------------------------------------------------------------------------|----------------------|
| [Flow](https://developer.android.com/reference/android/support/constraint/helper/Flow) | Flow virtual layout. |

## G

|-------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [Group](https://developer.android.com/reference/android/support/constraint/Group)         | **Added in 1.1** This class controls the visibility of a set of referenced widgets.                                                                              |
| [Guideline](https://developer.android.com/reference/android/support/constraint/Guideline) | Utility class representing a Guideline helper object for[ConstraintLayout](https://developer.android.com/reference/android/support/constraint/ConstraintLayout). |

## I

|-----------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------|
| [ImageFilterButton](https://developer.android.com/reference/android/support/constraint/utils/ImageFilterButton) | An ImageButton that can display, combine and filter images. |
| [ImageFilterView](https://developer.android.com/reference/android/support/constraint/utils/ImageFilterView)     | An ImageView that can display, combine and filter images.   |

## L

|------------------------------------------------------------------------------------------|------------------|
| [Layer](https://developer.android.com/reference/android/support/constraint/helper/Layer) | **Added in 2.0** |

## M

|----------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------|
| [MockView](https://developer.android.com/reference/android/support/constraint/utils/MockView)                                                | A view that is useful for prototyping layouts.                          |
| [MotionLayout](https://developer.android.com/reference/android/support/constraint/motion/MotionLayout)                                       | **A subclass of ConstraintLayout for building animations.**             |
| [MotionLayout.TransitionListener](https://developer.android.com/reference/android/support/constraint/motion/MotionLayout.TransitionListener) | **Added in 2.0** Listener for monitoring events about TransitionLayout. |

## P

|-----------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------|
| [Placeholder](https://developer.android.com/reference/android/support/constraint/Placeholder) | **Added in 1.1** A`Placeholder`provides a virtual object which can position an existing object. |

## T

|------------------------------------------------------------------------------------------------------------------|---|
| [TransitionAdapter](https://developer.android.com/reference/android/support/constraint/motion/TransitionAdapter) |   |