ConstraintHelper


public abstract class ConstraintHelper extends View

Known direct subclasses
Barrier

Added in 1.1

Group

Control the visibility and elevation of the referenced views Added in 1.1

Layer

Layer adds the ability to move and rotate a group of views as if they were contained in a viewGroup Added in 2.0 Methods such as setRotation(float) rotate all views about a common center.

MotionHelper
VirtualLayout

Added in 2.0

Known indirect subclasses
Carousel

Carousel works within a MotionLayout to provide a simple recycler like pattern.

CircularFlow

CircularFlow virtual layout.

Flow

Flow VirtualLayout.

Grid

A helper class that helps arrange widgets in a grid form

MotionEffect

MotionHelper that automatically inserts keyframes for views moving in a given direction, out of:

MotionPlaceholder

Added in 1.1

This class manages a set of referenced widgets. HelperWidget objects can be created to act upon the set of referenced widgets. The difference between ConstraintHelper and ViewGroup is that multiple ConstraintHelper can reference the same widgets.

Widgets are referenced by being added to a comma separated list of ids, e.g.:

        <androidx.constraintlayout.widget.Barrier
             android:id="@+id/barrier"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             app:barrierDirection="start"
             app:constraint_referenced_ids="button1,button2" />
    

Summary

Constants

static final String
CHILD_TAG = "CONSTRAINT_LAYOUT_HELPER_CHILD"

Public constructors

ConstraintHelper(Context context, AttributeSet attrs, int defStyleAttr)

Public methods

void
addView(View view)

Add a view to the helper.

void

hook for helpers to apply parameters in MotionLayout

boolean
containsId(int id)

does id table contain the id

int[]

Helpers typically reference a collection of ids

int
indexFromId(int id)

find the position of an id

static boolean
void
loadParameters(
    ConstraintSet.Constraint constraint,
    HelperWidget child,
    ConstraintLayout.LayoutParams layoutParams,
    SparseArray<ConstraintWidget> mapIdToWidget
)

Load the parameters

void
int

Remove a given view from the helper.

void
resolveRtl(ConstraintWidget widget, boolean isRtl)

resolve the RTL

void
setReferencedIds(int[] ids)

Helpers typically reference a collection of ids

void
setTag(int key, Object tag)
void

update after constraints are resolved

void

Allows a helper a chance to update its internal object post layout or set up connections for the pointed elements

void
void

called before the draw

void

Allows a helper a chance to update its internal object pre layout or set up connections for the pointed elements

void
updatePreLayout(
    ConstraintWidgetContainer container,
    Helper helper,
    SparseArray<ConstraintWidget> map
)

called before solver resolution

void

Allows a helper to replace the default ConstraintWidget in LayoutParams by its own subclass

Protected methods

void
void
void
View[]
void
void
void
onMeasure(int widthMeasureSpec, int heightMeasureSpec)
void
setIds(String idList)
void

Inherited Constants

From android.view.View
static final int
static final int
static final int
static final int
static final int
static final int
static final Property<ViewFloat>
static final int
static final String
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_DATE = "creditCardExpirationDate"
static final String
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_DAY = "creditCardExpirationDay"
static final String
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_MONTH = "creditCardExpirationMonth"
static final String
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_YEAR = "creditCardExpirationYear"
static final String
static final String
AUTOFILL_HINT_CREDIT_CARD_SECURITY_CODE = "creditCardSecurityCode"
static final String
static final String
static final String
static final String
static final String
static final String
static final String
static final int
static final int
static final int
static final int
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static final int
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static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int[]
static final int[]
static final int[]
static final int[]
static final int[]
static final int[]
static final int[]
static final int[]
static final int[]
static final int
static final int
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static final int[]
static final int[]
static final int[]
static final int[]
static final int
static final int
static final int
static final int
static final int
static final int
static final int
GONE = 8
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
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static final int
static final int
static final int
static final int
KEEP_SCREEN_ON = 67108864
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
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static final int
NO_ID = -1
static final int
static final int
static final int
static final int[]
static final int[]
static final int[]
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static final int[]
static final int[]
static final int[]
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static final int[]
static final int[]
static final int[]
static final int[]
static final int[]
static final int[]
static final Property<ViewFloat>
static final Property<ViewFloat>
static final Property<ViewFloat>
static final Property<ViewFloat>
static final Property<ViewFloat>
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
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static final int
static final int[]
static final int[]
static final int
static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int
static final int
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static final int
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static final int
static final int
static final int
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static final int
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static final int
static final int
static final int
static final Property<ViewFloat>
static final Property<ViewFloat>
static final Property<ViewFloat>
static final String
VIEW_LOG_TAG = "View"
static final int
static final int[]
static final Property<ViewFloat>
static final Property<ViewFloat>
static final Property<ViewFloat>

Inherited methods

From android.view.View
void
void
addExtraDataToAccessibilityNodeInfo(
    AccessibilityNodeInfo info,
    String extraDataKey,
    Bundle arguments
)
void
addFocusables(ArrayList<View> views, int direction)
void
void
void
void
void
ViewPropertyAnimator
void
void
boolean
void
void

This method is deprecated.

void
boolean
boolean
boolean
boolean
boolean
canScrollHorizontally(int direction)
boolean
canScrollVertically(int direction)
final void
void
final void
boolean
void
void
void
static int
combineMeasuredStates(int curState, int newState)
int
int
int
void
WindowInsets
int
int
int
AccessibilityNodeInfo
void
void

This method is deprecated.

WindowInsets
boolean
void
void
dispatchCreateViewTranslationRequest(
    Map<AutofillId, long[]> viewIds,
    int[] supportedFormats,
    TranslationCapability capability,
    List<ViewTranslationRequest> requests
)
void
boolean
void
void
dispatchDrawableHotspotChanged(float x, float y)
void
boolean
boolean
boolean
boolean
boolean
boolean
boolean
boolean
dispatchNestedFling(float velocityX, float velocityY, boolean consumed)
boolean
dispatchNestedPreFling(float velocityX, float velocityY)
boolean
dispatchNestedPrePerformAccessibilityAction(
    int action,
    Bundle arguments
)
boolean
dispatchNestedPreScroll(
    int dx,
    int dy,
    int[] consumed,
    int[] offsetInWindow
)
boolean
dispatchNestedScroll(
    int dxConsumed,
    int dyConsumed,
    int dxUnconsumed,
    int dyUnconsumed,
    int[] offsetInWindow
)
void
dispatchPointerCaptureChanged(boolean hasCapture)
boolean
void
void
void
void
void
dispatchScrollCaptureSearch(
    Rect localVisibleRect,
    Point windowOffset,
    Consumer<ScrollCaptureTarget> targets
)
void
dispatchSetActivated(boolean activated)
void
dispatchSetPressed(boolean pressed)
void
dispatchSetSelected(boolean selected)
void
void

This method is deprecated.

boolean
boolean
boolean
dispatchUnhandledMove(View focused, int direction)
void
dispatchVisibilityChanged(View changedView, int visibility)
void
dispatchWindowFocusChanged(boolean hasFocus)
void
void
WindowInsets
WindowInsetsAnimation.Bounds
void

This method is deprecated.

void
void
draw(Canvas canvas)
void
drawableHotspotChanged(float x, float y)
void
View
final OnBackInvokedDispatcher
final T
<T extends View> findViewById(int id)
final T
<T extends View> findViewWithTag(Object tag)
void
findViewsWithText(
    ArrayList<View> outViews,
    CharSequence searched,
    int flags
)
boolean

This method is deprecated.

View
focusSearch(int direction)
void
forceHasOverlappingRendering(boolean hasOverlappingRendering)
void
boolean
void
generateDisplayHash(
    String hashAlgorithm,
    Rect bounds,
    Executor executor,
    DisplayHashResultCallback callback
)
static int
CharSequence
View.AccessibilityDelegate
int
AccessibilityNodeProvider
CharSequence
int
int
String
String
float
Animation
Matrix
IBinder
int[]
Map<IntegerInteger>
String[]
final AutofillId
int
AutofillValue
Drawable
BlendMode
ColorStateList
PorterDuff.Mode
int
final int
float
int
float
Rect
boolean
final boolean
final ContentCaptureSession
CharSequence
final Context
ContextMenu.ContextMenuInfo
final boolean
static int
getDefaultSize(int size, int measureSpec)
Display
final int[]
Bitmap

This method is deprecated.

int

This method is deprecated.

int

This method is deprecated.

void
long
float
int
boolean
boolean
int
ArrayList<View>
getFocusables(int direction)
void
Drawable
int
BlendMode
ColorStateList
PorterDuff.Mode