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ConstraintLayout

class ConstraintLayout : ViewGroup

kotlin.Any
   ↳ android.view.View
     ↳ android.view.ViewGroup
       ↳ androidx.constraintlayout.widget.ConstraintLayout
Known direct subclasses
MotionLayout

A subclass of ConstraintLayout that supports animating between various states Added in 2.0

A ConstraintLayout is a android.view.ViewGroup which allows you to position and size widgets in a flexible way.

Note:ConstraintLayout is available as a support library that you can use on Android systems starting with API level 9 (Gingerbread). As such, we are planning on enriching its API and capabilities over time. This documentation will reflect those changes.

There are currently various types of constraints that you can use:

  • Relative positioning
  • Margins
  • Centering positioning
  • Circular positioning
  • Visibility behavior
  • Dimension constraints
  • Chains
  • Virtual Helpers objects
  • Optimizer

Note that you cannot have a circular dependency in constraints.

Also see ConstraintLayout.LayoutParams for layout attributes

Developer Guide

Relative positioning

Relative positioning is one of the basic building blocks of creating layouts in ConstraintLayout. Those constraints allow you to position a given widget relative to another one. You can constrain a widget on the horizontal and vertical axis:

  • Horizontal Axis: left, right, start and end sides
  • Vertical Axis: top, bottom sides and text baseline

The general concept is to constrain a given side of a widget to another side of any other widget.

For example, in order to position button B to the right of button A:

you would need to do: 

        <Button android:id="@+id/buttonA" ... />
        <Button android:id="@+id/buttonB" ...
                app:layout_constraintLeft_toRightOf="@+id/buttonA" />
This tells the system that we want the left side of button B to be constrained to the right side of button A. Such a position constraint means that the system will try to have both sides share the same location.

Here is the list of available constraints:

  • layout_constraintLeft_toLeftOf
  • layout_constraintLeft_toRightOf
  • layout_constraintRight_toLeftOf
  • layout_constraintRight_toRightOf
  • layout_constraintTop_toTopOf
  • layout_constraintTop_toBottomOf
  • layout_constraintBottom_toTopOf
  • layout_constraintBottom_toBottomOf
  • layout_constraintBaseline_toBaselineOf
  • layout_constraintStart_toEndOf
  • layout_constraintStart_toStartOf
  • layout_constraintEnd_toStartOf
  • layout_constraintEnd_toEndOf

They all take a reference id to another widget, or the parent (which will reference the parent container, i.e. the ConstraintLayout): 

        <Button android:id="@+id/buttonB" ...
                app:layout_constraintLeft_toLeftOf="parent" />

Margins

If side margins are set, they will be applied to the corresponding constraints (if they exist), enforcing the margin as a space between the target and the source side. The usual layout margin attributes can be used to this effect:

  • android:layout_marginStart
  • android:layout_marginEnd
  • android:layout_marginLeft
  • android:layout_marginTop
  • android:layout_marginRight
  • android:layout_marginBottom
  • layout_marginBaseline

Note that a margin can only be positive or equal to zero, and takes a Dimension.

Margins when connected to a GONE widget

When a position constraint target's visibility is View.GONE, you can also indicate a different margin value to be used using the following attributes:

  • layout_goneMarginStart
  • layout_goneMarginEnd
  • layout_goneMarginLeft
  • layout_goneMarginTop
  • layout_goneMarginRight
  • layout_goneMarginBottom
  • layout_goneMarginBaseline

Centering positioning and bias

A useful aspect of ConstraintLayout is in how it deals with "impossible" constraints. For example, if we have something like: 

        <androidx.constraintlayout.widget.ConstraintLayout ...>
            <Button android:id="@+id/button" ...
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintRight_toRightOf="parent"/>
        </>

Unless the ConstraintLayout happens to have the exact same size as the Button, both constraints cannot be satisfied at the same time (both sides cannot be where we want them to be).

What happens in this case is that the constraints act like opposite forces pulling the widget apart equally; such that the widget will end up being centered in the parent container. This will apply similarly for vertical constraints.

Bias

The default when encountering such opposite constraints is to center the widget; but you can tweak the positioning to favor one side over another using the bias attributes:

  • layout_constraintHorizontal_bias
  • layout_constraintVertical_bias

For example the following will make the left side with a 30% bias instead of the default 50%, such that the left side will be shorter, with the widget leaning more toward the left side: 

        <androidx.constraintlayout.widget.ConstraintLayout ...>
            <Button android:id="@+id/button" ...
                app:layout_constraintHorizontal_bias="0.3"
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintRight_toRightOf="parent"/>
        </>
Using bias, you can craft User Interfaces that will better adapt to screen sizes changes.

Circular positioning (Added in 1.1)

You can constrain a widget center relative to another widget center, at an angle and a distance. This allows you to position a widget on a circle. The following attributes can be used:

  • layout_constraintCircle : references another widget id
  • layout_constraintCircleRadius : the distance to the other widget center
  • layout_constraintCircleAngle : which angle the widget should be at (in degrees, from 0 to 360)
 <Button android:id="@+id/buttonA" ... />
 <Button android:id="@+id/buttonB" ...
     app:layout_constraintCircle="@+id/buttonA"
     app:layout_constraintCircleRadius="100dp"
     app:layout_constraintCircleAngle="45" />

Visibility behavior

ConstraintLayout has a specific handling of widgets being marked as View.GONE.

GONE widgets, as usual, are not going to be displayed and are not part of the layout itself (i.e. their actual dimensions will not be changed if marked as GONE).

But in terms of the layout computations, GONE widgets are still part of it, with an important distinction:

  • For the layout pass, their dimension will be considered as zero (basically, they will be resolved to a point)
  • If they have constraints to other widgets they will still be respected, but any margins will be as if equals to zero

This specific behavior allows to build layouts where you can temporarily mark widgets as being GONE, without breaking the layout, which can be particularly useful when doing simple layout animations.

Note: The margin used will be the margin that B had defined when connecting to A. In some cases, this might not be the margin you want (e.g. A had a 100dp margin to the side of its container, B only a 16dp to A, marking A as gone, B will have a margin of 16dp to the container). For this reason, you can specify an alternate margin value to be used when the connection is to a widget being marked as gone (see the section above about the gone margin attributes).

Dimensions constraints

Minimum dimensions on ConstraintLayout

You can define minimum and maximum sizes for the ConstraintLayout itself:

  • android:minWidth set the minimum width for the layout
  • android:minHeight set the minimum height for the layout
  • android:maxWidth set the maximum width for the layout
  • android:maxHeight set the maximum height for the layout
Those minimum and maximum dimensions will be used by ConstraintLayout when its dimensions are set to WRAP_CONTENT. Widgets dimension constraints

The dimension of the widgets can be specified by setting the android:layout_width and android:layout_height attributes in 3 different ways:

  • Using a specific dimension (either a literal value such as 123dp or a Dimension reference)
  • Using WRAP_CONTENT, which will ask the widget to compute its own size
  • Using 0dp, which is the equivalent of "MATCH_CONSTRAINT"

The first two works in a similar fashion as other layouts. The last one will resize the widget in such a way as matching the constraints that are set. If margins are set, they will be taken in account in the computation.

Important: MATCH_PARENT is not recommended for widgets contained in a ConstraintLayout. Similar behavior can be defined by using MATCH_CONSTRAINT with the corresponding left/right or top/bottom constraints being set to "parent".

WRAP_CONTENT : enforcing constraints (Added in 1.1)

If a dimension is set to WRAP_CONTENT, in versions before 1.1 they will be treated as a literal dimension -- meaning, constraints will not limit the resulting dimension. While in general this is enough (and faster), in some situations, you might want to use WRAP_CONTENT, yet keep enforcing constraints to limit the resulting dimension. In that case, you can add one of the corresponding attribute:

  • app:layout_constrainedWidth="true|false"
  • app:layout_constrainedHeight="true|false"
MATCH_CONSTRAINT dimensions (Added in 1.1)

When a dimension is set to MATCH_CONSTRAINT, the default behavior is to have the resulting size take all the available space. Several additional modifiers are available:

  • layout_constraintWidth_min and layout_constraintHeight_min : will set the minimum size for this dimension
  • layout_constraintWidth_max and layout_constraintHeight_max : will set the maximum size for this dimension
  • layout_constraintWidth_percent and layout_constraintHeight_percent : will set the size of this dimension as a percentage of the parent
Min and Max

The value indicated for min and max can be either a dimension in Dp, or "wrap", which will use the same value as what WRAP_CONTENT would do.

Percent dimension

To use percent, you need to set the following

  • The dimension should be set to MATCH_CONSTRAINT (0dp)
  • The default should be set to percent app:layout_constraintWidth_default="percent" or app:layout_constraintHeight_default="percent"
  • Then set the layout_constraintWidth_percent or layout_constraintHeight_percent attributes to a value between 0 and 1
Ratio

You can also define one dimension of a widget as a ratio of the other one. In order to do that, you need to have at least one constrained dimension be set to 0dp (i.e., MATCH_CONSTRAINT), and set the attribute layout_constraintDimensionRatio to a given ratio. For example: 

          <Button android:layout_width="wrap_content"
                  android:layout_height="0dp"
                  app:layout_constraintDimensionRatio="1:1" />
will set the height of the button to be the same as its width.

The ratio can be expressed either as:

  • a float value, representing a ratio between width and height
  • a ratio in the form "width:height"

You can also use ratio if both dimensions are set to MATCH_CONSTRAINT (0dp). In this case the system sets the largest dimensions that satisfies all constraints and maintains the aspect ratio specified. To constrain one specific side based on the dimensions of another, you can pre append W," or H, to constrain the width or height respectively. For example, If one dimension is constrained by two targets (e.g. width is 0dp and centered on parent) you can indicate which side should be constrained, by adding the letter W (for constraining the width) or H (for constraining the height) in front of the ratio, separated by a comma: 

          <Button android:layout_width="0dp"
                  android:layout_height="0dp"
                  app:layout_constraintDimensionRatio="H,16:9"
                  app:layout_constraintBottom_toBottomOf="parent"
                  app:layout_constraintTop_toTopOf="parent"/>
will set the height of the button following a 16:9 ratio, while the width of the button will match the constraints to its parent.

Chains

Chains provide group-like behavior in a single axis (horizontally or vertically). The other axis can be constrained independently.

Creating a chain

A set of widgets are considered a chain if they are linked together via a bi-directional connection.

Chain heads

Chains are controlled by attributes set on the first element of the chain (the "head" of the chain):

The head is the left-most widget for horizontal chains, and the top-most widget for vertical chains.

Margins in chains

If margins are specified on connections, they will be taken into account. In the case of spread chains, margins will be deducted from the allocated space.

Chain Style

When setting the attribute layout_constraintHorizontal_chainStyle or layout_constraintVertical_chainStyle on the first element of a chain, the behavior of the chain will change according to the specified style (default is CHAIN_SPREAD).

  • CHAIN_SPREAD -- the elements will be spread out (default style)
  • Weighted chain -- in CHAIN_SPREAD mode, if some widgets are set to MATCH_CONSTRAINT, they will split the available space
  • CHAIN_SPREAD_INSIDE -- similar, but the endpoints of the chain will not be spread out
  • CHAIN_PACKED -- the elements of the chain will be packed together. The horizontal or vertical bias attribute of the child will then affect the positioning of the packed elements
Weighted chains

The default behavior of a chain is to spread the elements equally in the available space. If one or more elements are using MATCH_CONSTRAINT, they will use the available empty space (equally divided among themselves). The attribute layout_constraintHorizontal_weight and layout_constraintVertical_weight will control how the space will be distributed among the elements using MATCH_CONSTRAINT. For example, on a chain containing two elements using MATCH_CONSTRAINT, with the first element using a weight of 2 and the second a weight of 1, the space occupied by the first element will be twice that of the second element.

Margins and chains (in 1.1)

When using margins on elements in a chain, the margins are additive.

For example, on a horizontal chain, if one element defines a right margin of 10dp and the next element defines a left margin of 5dp, the resulting margin between those two elements is 15dp.

An item plus its margins are considered together when calculating leftover space used by chains to position items. The leftover space does not contain the margins.

Virtual Helper objects

In addition to the intrinsic capabilities detailed previously, you can also use special helper objects in ConstraintLayout to help you with your layout. Currently, the Guideline{@see Guideline} object allows you to create Horizontal and Vertical guidelines which are positioned relative to the ConstraintLayout container. Widgets can then be positioned by constraining them to such guidelines. In 1.1, Barrier and Group were added too.

Optimizer (in 1.1)

In 1.1 we exposed the constraints optimizer. You can decide which optimizations are applied by adding the tag app:layout_optimizationLevel to the ConstraintLayout element.

  • none : no optimizations are applied
  • standard : Default. Optimize direct and barrier constraints only
  • direct : optimize direct constraints
  • barrier : optimize barrier constraints
  • chain : optimize chain constraints (experimental)
  • dimensions : optimize dimensions measures (experimental), reducing the number of measures of match constraints elements

This attribute is a mask, so you can decide to turn on or off specific optimizations by listing the ones you want. For example: app:layout_optimizationLevel="direct|barrier|chain"

Summary

Nested types

This class contains the different attributes specifying how a view want to be laid out inside a ConstraintLayout.

This is the interface to a valued modifier. implement this and add it using addValueModifier

Constants
const Int
const String!
VERSION = "ConstraintLayout-2.2.0-alpha04"

Public constructors
ConstraintLayout(context: Context, attrs: AttributeSet?)
ConstraintLayout(context: Context, attrs: AttributeSet?, defStyleAttr: Int)
@TargetApi(value = Build.VERSION_CODES.LOLLIPOP)
ConstraintLayout(
    context: Context,
    attrs: AttributeSet?,
    defStyleAttr: Int,
    defStyleRes: Int
)

Public functions
Unit

a ValueModify to the ConstraintLayout.
Unit
fillMetrics(metrics: Metrics!)
Unit
ConstraintLayout.LayoutParams!
Any!
getDesignInformation(type: Int, value: Any!)
Int

The maximum height of this view.
Int
Int

The minimum height of this view.
Int

The minimum width of this view.
Int

Return the current optimization level for the layout resolution
String!

Returns a JSON5 string useful for debugging the constraints actually applied.
java-static SharedValues!

Returns the SharedValues instance, creating it if it doesn't exist.
View!
ConstraintWidget!
Unit
loadLayoutDescription(layoutDescription: Int)

Load a layout description file from the resources.
Unit
onViewAdded(view: View!)
Unit
Unit
Unit

Sets a ConstraintSet object to manage constraints.
Unit
setDesignInformation(type: Int, value1: Any!, value2: Any!)
Unit
setId(id: Int)
Unit
setMaxHeight(value: Int)

Set the max height for this view
Unit
setMaxWidth(value: Int)

Set the max width for this view
Unit
setMinHeight(value: Int)

Set the min height for this view
Unit
setMinWidth(value: Int)

Set the min width for this view
Unit
setOnConstraintsChanged(
    constraintsChangedListener: ConstraintsChangedListener!
)

Notify of constraints changed
Unit

Set the optimization for the layout resolution.
Unit
setState(id: Int, screenWidth: Int, screenHeight: Int)

Set the State of the ConstraintLayout, causing it to load a particular ConstraintSet.
Boolean

Protected functions
Unit
applyConstraintsFromLayoutParams(
    isInEditMode: Boolean,
    child: View!,
    widget: ConstraintWidget!,
    layoutParams: ConstraintLayout.LayoutParams!,
    idToWidget: SparseArray<ConstraintWidget!>!
)
Boolean
Unit
dispatchDraw(canvas: Canvas!)
Boolean
dynamicUpdateConstraints(widthMeasureSpec: Int, heightMeasureSpec: Int)

This can be overridden to change the way Modifiers are used.
ConstraintLayout.LayoutParams!
ViewGroup.LayoutParams!
Boolean
Unit
onLayout(changed: Boolean, left: Int, top: Int, right: Int, bottom: Int)
Unit
onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int)
Unit

Subclasses can override the handling of layoutDescription
Unit
resolveMeasuredDimension(
    widthMeasureSpec: Int,
    heightMeasureSpec: Int,
    measuredWidth: Int,
    measuredHeight: Int,
    isWidthMeasuredTooSmall: Boolean,
    isHeightMeasuredTooSmall: Boolean
)

Handles calling setMeasuredDimension()
Unit
resolveSystem(
    layout: ConstraintWidgetContainer!,
    optimizationLevel: Int,
    widthMeasureSpec: Int,
    heightMeasureSpec: Int
)

Handles measuring a layout
Unit
setSelfDimensionBehaviour(
    layout: ConstraintWidgetContainer!,
    widthMode: Int,
    widthSize: Int,
    heightMode: Int,
    heightSize: Int
)

Protected properties
ConstraintLayoutStates!
Boolean
ConstraintWidgetContainer!

Inherited Constants
From android.view.View
const Int
const Int
const Int
const Int
const Int
const Int
const Property<View!, Float!>!
const Int
const String!
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_DATE = "creditCardExpirationDate"
const String!
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_DAY = "creditCardExpirationDay"
const String!
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_MONTH = "creditCardExpirationMonth"
const String!
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_YEAR = "creditCardExpirationYear"
const String!
const String!
AUTOFILL_HINT_CREDIT_CARD_SECURITY_CODE = "creditCardSecurityCode"
const String!
const String!
const String!
const String!
const String!
const String!
const String!
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const Int
const Int
const Int
const Int
const Int
const Int
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const Int
const Int
const Int
const Int
const Int
const Int
const Int
GONE = 8
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
KEEP_SCREEN_ON = 67108864
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
NO_ID = -1
const Int
const Int
const Int
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const IntArray<Int>!
const Float
const Float
const Float
const Float
const Float
const Property<View!, Float!>!
const Property<View!, Float!>!
const Property<View!, Float!>!
const Property<View!, Float!>!
const Property<View!, Float!>!
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const IntArray<Int>!
const IntArray<Int>!
const Int
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Int
const Property<View!, Float!>!
const Property<View!, Float!>!
const Property<View!, Float!>!
const String!
VIEW_LOG_TAG = "View"
const Int
const IntArray<Int>!
const Property<View!, Float!>!
const Property<View!, Float!>!
const Property<View!, Float!>!
From android.view.ViewGroup
const Int
const Int
const Int
const Int
const Int
const Int
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.
const Int

This property is deprecated.

Inherited functions
From android.view.View
Unit
Unit
Unit
ViewPropertyAnimator!
Unit

This function is deprecated.
Unit
Boolean
Unit
Unit

This function is deprecated.
Unit
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Unit
Unit
Unit
Boolean
Unit
Unit
Unit
java-static Int
combineMeasuredStates(curState: Int, newState: Int)
Int
Int
Int
Unit
WindowInsets!
computeSystemWindowInsets(in: WindowInsets!, outLocalInsets: Rect!)
Int
Int
Int
AccessibilityNodeInfo!
Unit
Unit

This function is deprecated.
Boolean
Boolean
dispatchNestedFling(velocityX: Float, velocityY: Float, consumed: Boolean)
Boolean
dispatchNestedPreFling(velocityX: Float, velocityY: Float)
Boolean
dispatchNestedPrePerformAccessibilityAction(
    action: Int,
    arguments: Bundle!
)
Boolean
dispatchNestedPreScroll(
    dx: Int,
    dy: Int,
    consumed: IntArray!,
    offsetInWindow: IntArray!
)
Boolean
dispatchNestedScroll(
    dxConsumed: Int,
    dyConsumed: Int,
    dxUnconsumed: Int,
    dyUnconsumed: Int,
    offsetInWindow: IntArray!
)
Boolean
Unit
draw(canvas: Canvas!)
Unit
OnBackInvokedDispatcher!
T!
<T : View?> findViewById(id: Int)
T!
<T : View?> findViewWithTag(tag: Any!)
Boolean

This function is deprecated.
Unit
forceHasOverlappingRendering(hasOverlappingRendering: Boolean)
Unit
generateDisplayHash(
    hashAlgorithm: String!,
    bounds: Rect!,
    executor: Executor!,
    callback: DisplayHashResultCallback!
)
java-static Int
View.AccessibilityDelegate!
Int
AccessibilityNodeProvider!
CharSequence!
Int
Int
String!
String!
Float
Animation!
Matrix!
IBinder!
IntArray<Int>!
(Mutable)Map<Int!, Int!>!
Array<String!>!
AutofillId!
Int
AutofillValue!
Drawable!
BlendMode!
ColorStateList!
PorterDuff.Mode!
Int
Int
Float
Int
Float
Rect!
Boolean
getClipBounds(outRect: Rect!)
Boolean
ContentCaptureSession!
CharSequence!
Int
Context!
ContextMenu.ContextMenuInfo!
Boolean
java-static Int
getDefaultSize(size: Int, measureSpec: Int)
Display!
IntArray<Int>!
Bitmap!

This function is deprecated.
Int

This function is deprecated.
Int

This function is deprecated.
Unit
getDrawingRect(outRect: Rect!)
Long
Float
Int
Boolean
Boolean
Int
ArrayList<View!>!
getFocusables(direction: Int)
Unit
Drawable!
Int
BlendMode!
ColorStateList!
PorterDuff.Mode!
Float
Boolean
Handler!
Float
Float
Float
Float
Int
Runnable!
Boolean
Int
Unit
getHitRect(outRect: Rect!)
Int
Int
Drawable!
Drawable!
Int
Int
Int
Int
Boolean
KeyEvent.DispatcherState!
Int
Int
Int
ViewGroup.LayoutParams!
Int
Float
Int
Boolean
Unit
Unit
Unit
Matrix!
Int
Int
Int
Int
Int
Int
Int
Int
Int
Int
Int
Int
Int
View.OnFocusChangeListener!
Int
ViewOutlineProvider!
Int
Int
ViewOverlay!
Int
Int
Int
Int
Int
Int
ViewParent!
ViewParent!
OutcomeReceiver<GetCredentialResponse!, GetCredentialException!>!
GetCredentialRequest!
Float
Float
PointerIcon!
(Mutable)List<Rect!>!
Array<String!>!
Float
Resources!
Boolean
Int
Float
Int
AttachedSurfaceControl!
View!
WindowInsets!
Float
Float
Float
Float
Float
Int
Int
Int
Int
Int
Int
Int
Int
Int
Int
CharSequence!
StateListAnimator!
Int
Int
CharSequence!
(Mutable)List<Rect!>!
Int

This function is deprecated.
Any!
Int
Int
CharSequence!
Int
Float
Int
TouchDelegate!
ArrayList<View!>!
Float
String!
Float
Float
Float
Long
Int
Int
Drawable!
Drawable!
Int
ViewTranslationResponse!
ViewTreeObserver!
Int
Int
Int
WindowId!
WindowInsetsController!
Int

This function is deprecated.
IBinder!
Int
Unit
Float
Float
Float
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
java-static View!
inflate(context: Context!, resource: Int, root: ViewGroup!)
Unit
Unit
Unit
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean

This function is deprecated.
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
View!
keyboardNavigationClusterSearch(currentCluster: View!, direction: Int)
Unit
measure(widthMeasureSpec: Int, heightMeasureSpec: Int)
java-static IntArray<Int>!
mergeDrawableStates(baseState: IntArray!, additionalState: IntArray!)
Unit
Unit
Unit
Unit
WindowInsets!
Unit
Boolean
Boolean
Unit
Unit
InputConnection!
Unit
onCreateViewTranslationRequest(
    supportedFormats: IntArray!,
    requestsCollector: Consumer<ViewTranslationRequest!>!
)
Unit
onCreateVirtualViewTranslationRequests(
    virtualIds: LongArray!,
    supportedFormats: IntArray!,
    requestsCollector: Consumer<ViewTranslationRequest!>!
)
Unit
Boolean
Unit
onDraw(canvas: Canvas!)
Unit
Unit
Boolean
Unit
Unit
Unit
onFocusChanged(
    gainFocus: Boolean,
    direction: Int,
    previouslyFocusedRect: Rect!
)
Boolean
Unit
Boolean
Unit
Unit
Boolean
onKeyDown(keyCode: Int, event: KeyEvent!)
Boolean
onKeyLongPress(keyCode: Int, event: KeyEvent!)
Boolean
onKeyMultiple(keyCode: Int, repeatCount: Int, event: KeyEvent!)
Boolean
onKeyPreIme(keyCode: Int, event: KeyEvent!)
Boolean
onKeyShortcut(keyCode: Int, event: KeyEvent!)
Boolean
onKeyUp(keyCode: Int, event: KeyEvent!)
Unit
onOverScrolled(
    scrollX: Int,
    scrollY: Int,
    clampedX: Boolean,
    clampedY: Boolean
)
Unit
Unit
Unit
Unit
Unit
Unit
Unit
ContentInfo!
Unit
Unit
onRtlPropertiesChanged(layoutDirection: Int)
Parcelable!
Unit
onScreenStateChanged(screenState: Int)
Unit
onScrollCaptureSearch(
    localVisibleRect: Rect!,
    windowOffset: Point!,
    targets: Consumer<ScrollCaptureTarget!>!
)
Unit
onScrollChanged(l: Int, t: Int, oldl: Int, oldt: Int)
Boolean
onSetAlpha(alpha: Int)
Unit
onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int)
Unit
Boolean
Boolean
Unit
Unit
Unit
Unit
onVisibilityChanged(changedView: View!, visibility: Int)
Unit
onWindowFocusChanged(hasWindowFocus: Boolean)
Unit

This function is deprecated.
Unit
Boolean
overScrollBy(
    deltaX: Int,
    deltaY: Int,
    scrollX: Int,
    scrollY: Int,
    scrollRangeX: Int,
    scrollRangeY: Int,
    maxOverScrollX: Int,
    maxOverScrollY: Int,
    isTouchEvent: Boolean
)
Boolean
performAccessibilityAction(action: Int, arguments: Bundle!)
Boolean
Boolean
Boolean
performHapticFeedback(feedbackConstant: Int)
Boolean
ContentInfo!
Unit
playSoundEffect(soundConstant: Int)
Boolean
post(action: Runnable!)
Boolean
postDelayed(action: Runnable!, delayMillis: Long)
Unit
Unit
postInvalidateDelayed(delayMilliseconds: Long)
Unit
Unit
Unit
postOnAnimationDelayed(action: Runnable!, delayMillis: Long)
Unit
Unit
Boolean
Unit
Unit
Unit
Unit
Unit
Unit

This function is deprecated.
Boolean
Unit
Boolean
Unit
T!
<T : View?> requireViewById(id: Int)
Unit
java-static Int
resolveSize(size: Int, measureSpec: Int)
java-static Int
resolveSizeAndState(size: Int, measureSpec: Int, childMeasuredState: Int)
Unit
Unit
saveAttributeDataForStyleable(
    context: Context!,
    styleable: IntArray!,
    attrs: AttributeSet!,
    t: TypedArray!,
    defStyleAttr: Int,
    defStyleRes: Int
)
Unit
Unit
scheduleDrawable(who: Drawable!, what: Runnable!, when: Long)
Unit
scrollBy(x: Int, y: Int)
Unit
scrollTo(x: Int, y: Int)
Unit
Unit
Unit
setAccessibilityDataSensitive(accessibilityDataSensitive: Int)
Unit
Unit
Unit
Unit
setAccessibilityPaneTitle(accessibilityPaneTitle: CharSequence!)
Unit
Unit
Unit
setActivated(activated: Boolean)
Unit
setAllowClickWhenDisabled(clickableWhenDisabled: Boolean)
Unit
Unit
Unit
setAlpha(alpha: Float)
Unit
setAnimation(animation: Animation!)
Unit
Unit
Unit
setAutofillHints(autofillHints: Array<String!>!)
Unit
Unit
setBackground(background: Drawable!)
Unit
Unit

This function is deprecated.
Unit
Unit
Unit
Unit
Unit
setBottom(bottom: Int)
Unit
Unit
setClickable(clickable: Boolean)
Unit
setClipBounds(clipBounds: Rect!)
Unit
setClipToOutline(clipToOutline: Boolean)
Unit
Unit
setContentDescription(contentDescription: CharSequence!)
Unit
Unit
setContextClickable(contextClickable: Boolean)
Unit
setDefaultFocusHighlightEnabled(defaultFocusHighlightEnabled: Boolean)
Unit

This function is deprecated.
Unit

This function is deprecated.
Unit

This function is deprecated.
Unit
Unit
setElevation(elevation: Float)
Unit
setEnabled(enabled: Boolean)
Unit
Unit
Unit
setFitsSystemWindows(fitSystemWindows: Boolean)
Unit
setFocusable(focusable: Boolean)
Unit
setFocusableInTouchMode(focusableInTouchMode: Boolean)
Unit
setFocusedByDefault(isFocusedByDefault: Boolean)
Unit
Unit
setForeground(foreground: Drawable!)
Unit
Unit
Unit
Unit
Unit
setFrameContentVelocity(pixelsPerSecond: Float)
Unit
setHandwritingBoundsOffsets(
    offsetLeft: Float,
    offsetTop: Float,
    offsetRight: Float,
    offsetBottom: Float
)
Unit
Unit
Unit
setHapticFeedbackEnabled(hapticFeedbackEnabled: Boolean)
Unit
setHasTransientState(hasTransientState: Boolean)
Unit
setHorizontalFadingEdgeEnabled(horizontalFadingEdgeEnabled: Boolean)
Unit
setHorizontalScrollBarEnabled(horizontalScrollBarEnabled: Boolean)
Unit
Unit
Unit
setHovered(hovered: Boolean)
Unit
Unit
Unit
Unit
setIsCredential(isCredential: Boolean)
Unit
setIsHandwritingDelegate(isHandwritingDelegate: Boolean)
Unit
setKeepScreenOn(keepScreenOn: Boolean)
Unit
Unit
Unit
Unit
setLayerType(layerType: Int, paint: Paint!)
Unit
setLayoutDirection(layoutDirection: Int)
Unit
Unit
setLeft(left: Int)
Unit
setLeftTopRightBottom(left: Int, top: Int, right: Int, bottom: Int)
Unit
setLongClickable(longClickable: Boolean)
Unit
setMeasuredDimension(measuredWidth: Int, measuredHeight: Int)
Unit
setMinimumHeight(minHeight: Int)
Unit
setMinimumWidth(minWidth: Int)
Unit
Unit
setNextClusterForwardId(nextClusterForwardId: Int)
Unit
setNextFocusDownId(nextFocusDownId: Int)
Unit
setNextFocusForwardId(nextFocusForwardId: Int)
Unit
setNextFocusLeftId(nextFocusLeftId: Int)
Unit
setNextFocusRightId(nextFocusRightId: Int)
Unit
setNextFocusUpId(nextFocusUpId: Int)
Unit
Unit
Unit
Unit
Unit
Unit
Unit
Unit
Unit
Unit
Unit
Unit
setOnReceiveContentListener(
    mimeTypes: Array<String!>!,
    listener: OnReceiveContentListener!
)
Unit
Unit

This function is deprecated.
Unit
Unit
Unit
Unit
Unit
setOverScrollMode(overScrollMode: Int)
Unit
setPadding(left: Int, top: Int, right: Int, bottom: Int)
Unit
setPaddingRelative(start: Int, top: Int, end: Int, bottom: Int)
Unit
Unit
setPivotX(pivotX: Float)
Unit
setPivotY(pivotY: Float)
Unit
setPointerIcon(pointerIcon: PointerIcon!)
Unit
setPreferKeepClear(preferKeepClear: Boolean)
Unit
Unit
setPressed(pressed: Boolean)
Unit
setRenderEffect(renderEffect: RenderEffect!)
Unit
setRevealOnFocusHint(revealOnFocus: Boolean)
Unit
setRight(right: Int)
Unit
setRotation(rotation: Float)
Unit
setRotationX(rotationX: Float)
Unit
setRotationY(rotationY: Float)
Unit
Unit
Unit
setScaleX(scaleX: Float)
Unit
setScaleY(scaleY: Float)
Unit
setScreenReaderFocusable(screenReaderFocusable: Boolean)
Unit
setScrollBarDefaultDelayBeforeFade(
    scrollBarDefaultDelayBeforeFade: Int
)
Unit
setScrollBarFadeDuration(scrollBarFadeDuration: Int)
Unit
setScrollBarSize(scrollBarSize: Int)
Unit
Unit
Unit
Unit
setScrollContainer(isScrollContainer: Boolean)
Unit
setScrollIndicators(indicators: Int)
Unit
setScrollX(value: Int)
Unit
setScrollY(value: Int)
Unit
Unit
setSelected(selected: Boolean)
Unit
setSoundEffectsEnabled(soundEffectsEnabled: Boolean)
Unit
setStateDescription(stateDescription: CharSequence!)
Unit
Unit
setSupplementalDescription(supplementalDescription: CharSequence!)
Unit
Unit

This function is deprecated.
Unit
setTag(key: Int, tag: Any!)
Unit
setTextAlignment(textAlignment: Int)
Unit
setTextDirection(textDirection: Int)
Unit
Unit
setTop(top: Int)
Unit
Unit
Unit
setTransitionName(transitionName: String!)
Unit
Unit
setTranslationX(translationX: Float)
Unit
setTranslationY(translationY: Float)
Unit
setTranslationZ(translationZ: Float)
Unit
setVerticalFadingEdgeEnabled(verticalFadingEdgeEnabled: Boolean)
Unit
setVerticalScrollBarEnabled(verticalScrollBarEnabled: Boolean)
Unit
Unit
Unit
Unit
Unit
setVisibility(visibility: Int)
Unit
setWillNotCacheDrawing(willNotCacheDrawing: Boolean)

This function is deprecated.
Unit
setWillNotDraw(willNotDraw: Boolean)
Unit
setX(x: Float)
Unit
setY(y: Float)
Unit
setZ(z: Float)
Boolean
ActionMode!
Unit
Boolean
startDrag(
    data: ClipData!,
    shadowBuilder: View.DragShadowBuilder!,
    myLocalState: Any!,
    flags: Int
)

This function is deprecated.
Boolean
startDragAndDrop(
    data: ClipData!,
    shadowBuilder: View.DragShadowBuilder!,
    myLocalState: Any!,
    flags: Int
)
Boolean
Unit
String!
Unit
Unit
Unit
Unit
Boolean
Boolean

This function is deprecated.
Boolean
From android.view.ViewGroup
Unit
Unit
addExtraDataToAccessibilityNodeInfo(
    info: AccessibilityNodeInfo!,
    extraDataKey: String!,
    arguments: Bundle!
)
Unit
addFocusables(views: ArrayList<View!>!, direction: Int, focusableMode: Int)
Unit
addKeyboardNavigationClusters(
    views: (Mutable)Collection<View!>!,
    direction: Int
)
Boolean
Unit
Unit
addView(child: View!)
Boolean
addViewInLayout(child: View!, index: Int, params: ViewGroup.LayoutParams!)
Unit
attachLayoutAnimationParameters(
    child: View!,
    params: ViewGroup.LayoutParams!,
    index: Int,
    count: Int
)
Unit
attachViewToParent(child: View!, index: Int, params: ViewGroup.LayoutParams!)
Unit
Boolean
Unit
Unit
childHasTransientStateChanged(
    child: View!,
    childHasTransientState: Boolean
)
Unit
Unit
Unit
Unit
Unit
debug(depth: Int)
Unit
Unit
Unit
detachViewsFromParent(start: Int, count: Int)
WindowInsets!
Boolean
Unit
Unit
dispatchCreateViewTranslationRequest(
    viewIds: (Mutable)Map<AutofillId!, LongArray!>!,
    supportedFormats: IntArray!,
    capability: TranslationCapability!,
    requests: (Mutable)List<ViewTranslationRequest!>!
)
Unit
Boolean
Unit
Unit
Unit
Boolean
Boolean
Boolean
Boolean
Boolean
Boolean
Unit
Unit
Unit
Unit
Unit
Unit
dispatchScrollCaptureSearch(
    localVisibleRect: Rect!,
    windowOffset: Point!,
    targets: Consumer<ScrollCaptureTarget!>!
)
Unit
Unit
Unit
Unit
Unit

This function is deprecated.
Unit
Boolean
Boolean
Boolean
dispatchUnhandledMove(focused: View!, direction: Int)
Unit
dispatchVisibilityChanged(changedView: View!, visibility: Int)
Unit
Unit
Unit
WindowInsets!
dispatchWindowInsetsAnimationProgress(
    insets: WindowInsets!,
    runningAnimations: (Mutable)List<WindowInsetsAnimation!>!
)
WindowInsetsAnimation.Bounds!
Unit

This function is deprecated.
Unit
Boolean
drawChild(canvas: Canvas!, child: View!, drawingTime: Long)
Unit
Unit
View!
OnBackInvokedDispatcher!
Unit
findViewsWithText(
    outViews: ArrayList<View!>!,
    text: CharSequence!,
    flags: Int
)
View!
focusSearch(focused: View!, direction: Int)
Unit
Boolean
CharSequence!
View!
getChildAt(index: Int)
Int
Int
getChildDrawingOrder(drawingPosition: Int)
java-static Int
getChildMeasureSpec(spec: Int, padding: Int, childDimension: Int)
Boolean
Boolean
getChildVisibleRect(child: View!, r: Rect!, offset: Point!)
Boolean
Boolean
Int
View!
LayoutAnimationController!
Animation.AnimationListener!
Int
LayoutTransition!
Int
ViewGroupOverlay!
Int

This function is deprecated.
Boolean
Boolean
Boolean
Int
indexOfChild(child: View!)
Unit
invalidateChild(child: View!, dirty: Rect!)

This function is deprecated.
ViewParent!
invalidateChildInParent(location: IntArray!, dirty: Rect!)

This function is deprecated.
Boolean

This function is deprecated.
Boolean

This function is deprecated.
Boolean
Boolean

This function is deprecated.
Boolean
Boolean
Boolean
Unit
Unit
layout(l: Int, t: Int, r: Int, b: Int)
Unit
measureChild(
    child: View!,
    parentWidthMeasureSpec: Int,
    parentHeightMeasureSpec: Int
)
Unit
measureChildWithMargins(
    child: View!,
    parentWidthMeasureSpec: Int,
    widthUsed: Int,
    parentHeightMeasureSpec: Int,
    heightUsed: Int
)
Unit
measureChildren(widthMeasureSpec: Int, heightMeasureSpec: Int)
Unit
notifySubtreeAccessibilityStateChanged(
    child: View!,
    source: View!,
    changeType: Int
)
Unit
offsetDescendantRectToMyCoords(descendant: View!, rect: Rect!)
Unit
offsetRectIntoDescendantCoords(descendant: View!, rect: Rect!)
Unit
IntArray<Int>!
Unit
onDescendantInvalidated(child: View!, target: View!)
Unit
Boolean
Boolean
Boolean
onNestedFling(
    target: View!,
    velocityX: Float,
    velocityY: Float,
    consumed: Boolean
)
Boolean
onNestedPreFling(target: View!, velocityX: Float, velocityY: Float)
Boolean
onNestedPrePerformAccessibilityAction(
    target: View!,
    action: Int,
    args: Bundle!
)
Unit
onNestedPreScroll(target: View!, dx: Int, dy: Int, consumed: IntArray!)
Unit
onNestedScroll(
    target: View!,
    dxConsumed: Int,
    dyConsumed: Int,
    dxUnconsumed: Int,
    dyUnconsumed: Int
)
Unit
onNestedScrollAccepted(child: View!, target: View!, axes: Int)
Boolean
onRequestFocusInDescendants(direction: Int, previouslyFocusedRect: Rect!)
Boolean
PointerIcon!
onResolvePointerIcon(event: MotionEvent!, pointerIndex: Int)
Boolean
onStartNestedScroll(child: View!, target: View!, nestedScrollAxes: Int)
Unit
Unit
propagateRequestedFrameRate(frameRate: Float, forceOverride: Boolean)
Unit
Unit
Unit
Unit
removeDetachedView(child: View!, animate: Boolean)
Unit
removeView(view: View!)
Unit
removeViewAt(index: Int)
Unit
Unit
removeViews(start: Int, count: Int)
Unit
removeViewsInLayout(start: Int, count: Int)
Unit
requestChildFocus(child: View!, focused: View!)
Boolean
requestChildRectangleOnScreen(
    child: View!,
    rectangle: Rect!,
    immediate: Boolean
)
Unit
Boolean
requestFocus(direction: Int, previouslyFocusedRect: Rect!)
Boolean
Unit
Boolean
Unit
Unit
Unit

This function is deprecated.
Unit

This function is deprecated.
Unit

This function is deprecated.
Unit
Unit

This function is deprecated.
Unit
setClipChildren(clipChildren: Boolean)
Unit
setClipToPadding(clipToPadding: Boolean)
Unit
Unit
Unit
Unit
setLayoutMode(layoutMode: Int)
Unit
Unit
Unit
Unit
setPersistentDrawingCache(drawingCacheToKeep: Int)

This function is deprecated.
Unit
Unit
Unit
setTouchscreenBlocksFocus(touchscreenBlocksFocus: Boolean)
Unit
setTransitionGroup(isTransitionGroup: Boolean)
Unit
Boolean
showContextMenuForChild(originalView: View!)
ActionMode!
startActionModeForChild(
    originalView: View!,
    callback: ActionMode.Callback!
)
Unit
Unit
Unit
Unit

Constants

DESIGN_INFO_ID

Added in 2.2.1
const val DESIGN_INFO_ID = 0: Int

VERSION

Added in 2.2.1
const val VERSION = "ConstraintLayout-2.2.0-alpha04": String!

Public constructors

ConstraintLayout

Added in 2.2.1
ConstraintLayout(context: Context)

ConstraintLayout

Added in 2.2.1
ConstraintLayout(context: Context, attrs: AttributeSet?)

ConstraintLayout

Added in 2.2.1
ConstraintLayout(context: Context, attrs: AttributeSet?, defStyleAttr: Int)

ConstraintLayout

Added in 2.2.1
@TargetApi(value = Build.VERSION_CODES.LOLLIPOP)
ConstraintLayout(
    context: Context,
    attrs: AttributeSet?,
    defStyleAttr: Int,
    defStyleRes: Int
)

Public functions

addValueModifier

Added in 2.2.1
fun addValueModifier(modifier: ConstraintLayout.ValueModifier!): Unit

a ValueModify to the ConstraintLayout. This can be useful to add custom behavour to the ConstraintLayout or address limitation of the capabilities of Constraint Layout

Parameters
modifier: ConstraintLayout.ValueModifier!

fillMetrics

Added in 2.2.1
fun fillMetrics(metrics: Metrics!): Unit
Parameters
metrics: Metrics!

Fills metrics object

forceLayout

fun forceLayout(): Unit

generateLayoutParams

Added in 2.2.1
fun generateLayoutParams(attrs: AttributeSet!): ConstraintLayout.LayoutParams!

getDesignInformation

Added in 2.2.1
fun getDesignInformation(type: Int, value: Any!): Any!

getMaxHeight

Added in 2.2.1
fun getMaxHeight(): Int

The maximum height of this view.

Returns
Int

The maximum height of this view
See also
setMaxHeight

getMaxWidth

Added in 2.2.1
fun getMaxWidth(): Int

getMinHeight

Added in 2.2.1
fun getMinHeight(): Int

The minimum height of this view.

Returns
Int

The minimum height of this view
See also
setMinHeight

getMinWidth

Added in 2.2.1
fun getMinWidth(): Int

The minimum width of this view.

Returns
Int

The minimum width of this view
See also
setMinWidth

getOptimizationLevel

Added in 2.2.1
fun getOptimizationLevel(): Int

Return the current optimization level for the layout resolution

Returns
Int

the current level

getSceneString

Added in 2.2.1
fun getSceneString(): String!

Returns a JSON5 string useful for debugging the constraints actually applied. In situations where a complex set of code dynamically constructs constraints it is useful to be able to query the layout for what are the constraints.

Returns
String!

json5 string representing the constraint in effect now.

getSharedValues

Added in 2.2.1
java-static fun getSharedValues(): SharedValues!

Returns the SharedValues instance, creating it if it doesn't exist.

Returns
SharedValues!

the SharedValues instance

getViewById

Added in 2.2.1
fun getViewById(id: Int): View!
Parameters
id: Int

the view id
Returns
View!

the child view, can return null Return a direct child view by its id if it exists

getViewWidget

Added in 2.2.1
fun getViewWidget(view: View!): ConstraintWidget!
Parameters
view: View!
Returns
ConstraintWidget!

loadLayoutDescription

Added in 2.2.1
fun loadLayoutDescription(layoutDescription: Int): Unit

Load a layout description file from the resources.

Parameters
layoutDescription: Int

The resource id, or 0 to reset the layout description.

onViewAdded

fun onViewAdded(view: View!): Unit

onViewRemoved

fun onViewRemoved(view: View!): Unit

requestLayout

fun requestLayout(): Unit

setConstraintSet

Added in 2.2.1
fun setConstraintSet(set: ConstraintSet!): Unit

Sets a ConstraintSet object to manage constraints. The ConstraintSet overrides LayoutParams of child views.

Parameters
set: ConstraintSet!

Layout children using ConstraintSet

setDesignInformation

Added in 2.2.1
fun setDesignInformation(type: Int, value1: Any!, value2: Any!): Unit

setId

fun setId(id: Int): Unit

setMaxHeight

Added in 2.2.1
fun setMaxHeight(value: Int): Unit

Set the max height for this view

Parameters
value: Int

setMaxWidth

Added in 2.2.1
fun setMaxWidth(value: Int): Unit

Set the max width for this view

Parameters
value: Int

setMinHeight

Added in 2.2.1
fun setMinHeight(value: Int): Unit

Set the min height for this view

Parameters
value: Int

setMinWidth

Added in 2.2.1
fun setMinWidth(value: Int): Unit

Set the min width for this view

Parameters
value: Int

setOnConstraintsChanged

Added in 2.2.1
fun setOnConstraintsChanged(
    constraintsChangedListener: ConstraintsChangedListener!
): Unit

Notify of constraints changed

Parameters
constraintsChangedListener: ConstraintsChangedListener!

setOptimizationLevel

Added in 2.2.1
fun setOptimizationLevel(level: Int): Unit

Set the optimization for the layout resolution.

The optimization can be any of the following:

  • Optimizer.OPTIMIZATION_NONE
  • Optimizer.OPTIMIZATION_STANDARD
  • a mask composed of specific optimizations
The mask can be composed of any combination of the following:
  • Optimizer.OPTIMIZATION_DIRECT
  • Optimizer.OPTIMIZATION_BARRIER
  • Optimizer.OPTIMIZATION_CHAIN (experimental)
  • Optimizer.OPTIMIZATION_DIMENSIONS (experimental)
Note that the current implementation of Optimizer.OPTIMIZATION_STANDARD is as a mask of DIRECT and BARRIER.
Parameters
level: Int

optimization level

setState

Added in 2.2.1
fun setState(id: Int, screenWidth: Int, screenHeight: Int): Unit

Set the State of the ConstraintLayout, causing it to load a particular ConstraintSet. For states with variants the variant with matching width and height constraintSet will be chosen

Parameters
id: Int

the constraint set state
screenWidth: Int

the width of the screen in pixels
screenHeight: Int

the height of the screen in pixels

shouldDelayChildPressedState

fun shouldDelayChildPressedState(): Boolean
Returns
Boolean

Protected functions

applyConstraintsFromLayoutParams

Added in 2.2.1
protected fun applyConstraintsFromLayoutParams(
    isInEditMode: Boolean,
    child: View!,
    widget: ConstraintWidget!,
    layoutParams: ConstraintLayout.LayoutParams!,
    idToWidget: SparseArray<ConstraintWidget!>!
): Unit

checkLayoutParams

protected fun checkLayoutParams(p: ViewGroup.LayoutParams!): Boolean

dispatchDraw

protected fun dispatchDraw(canvas: Canvas!): Unit

dynamicUpdateConstraints

Added in 2.2.1
protected fun dynamicUpdateConstraints(widthMeasureSpec: Int, heightMeasureSpec: Int): Boolean

This can be overridden to change the way Modifiers are used.

Parameters
widthMeasureSpec: Int
heightMeasureSpec: Int
Returns
Boolean

generateDefaultLayoutParams

Added in 2.2.1
protected fun generateDefaultLayoutParams(): ConstraintLayout.LayoutParams!

generateLayoutParams

protected fun generateLayoutParams(p: ViewGroup.LayoutParams!): ViewGroup.LayoutParams!

isRtl

Added in 2.2.1
protected fun isRtl(): Boolean

onLayout

protected fun onLayout(changed: Boolean, left: Int, top: Int, right: Int, bottom: Int): Unit

onMeasure

protected fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int): Unit

parseLayoutDescription

Added in 2.2.1
protected fun parseLayoutDescription(id: Int): Unit

Subclasses can override the handling of layoutDescription

Parameters
id: Int

resolveMeasuredDimension

Added in 2.2.1
protected fun resolveMeasuredDimension(
    widthMeasureSpec: Int,
    heightMeasureSpec: Int,
    measuredWidth: Int,
    measuredHeight: Int,
    isWidthMeasuredTooSmall: Boolean,
    isHeightMeasuredTooSmall: Boolean
): Unit

Handles calling setMeasuredDimension()

Parameters
widthMeasureSpec: Int
heightMeasureSpec: Int
measuredWidth: Int
measuredHeight: Int
isWidthMeasuredTooSmall: Boolean
isHeightMeasuredTooSmall: Boolean

resolveSystem

Added in 2.2.1
protected fun resolveSystem(
    layout: ConstraintWidgetContainer!,
    optimizationLevel: Int,
    widthMeasureSpec: Int,
    heightMeasureSpec: Int
): Unit

Handles measuring a layout

Parameters
layout: ConstraintWidgetContainer!
optimizationLevel: Int
widthMeasureSpec: Int
heightMeasureSpec: Int

setSelfDimensionBehaviour

Added in 2.2.1
protected fun setSelfDimensionBehaviour(
    layout: ConstraintWidgetContainer!,
    widthMode: Int,
    widthSize: Int,
    heightMode: Int,
    heightSize: Int
): Unit

Protected properties

mConstraintLayoutSpec

Added in 2.2.1
protected val mConstraintLayoutSpec: ConstraintLayoutStates!

mDirtyHierarchy

Added in 2.2.1
protected val mDirtyHierarchy: Boolean

mLayoutWidget

Added in 2.2.1
protected val mLayoutWidget: ConstraintWidgetContainer!
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