ConstraintHelper

Artifact: androidx.constraintlayout:constraintlayout

Added in 2.2.1

Kotlin |Java

public abstract class ConstraintHelper extends View

java.lang.Object
↳	android.view.View
	↳	androidx.constraintlayout.widget.ConstraintHelper

Known direct subclasses

Barrier, Group, Layer, MotionHelper, VirtualLayout

`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, CircularFlow, Flow, Grid, MotionEffect, MotionPlaceholder

`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"`

Protected fields
`int`	`mCount`
`Helper`	`mHelperWidget`
`int[]`	`mIds`
`HashMap<Integer, String>`	`mMap`
`String`	`mReferenceIds`
`String`	`mReferenceTags`
`boolean`	`mUseViewMeasure`
`Context`	`myContext`

Public constructors
`ConstraintHelper(Context context)`
`ConstraintHelper(Context context, AttributeSet attrs)`
`ConstraintHelper(Context context, AttributeSet attrs, int defStyleAttr)`

Public methods
`void`	`addView(View view)` Add a view to the helper.
`void`	`applyHelperParams()` hook for helpers to apply parameters in MotionLayout
`boolean`	`containsId(int id)` does id table contain the id
`int[]`	`getReferencedIds()` Helpers typically reference a collection of ids
`int`	`indexFromId(int id)` find the position of an id
`static boolean`	`isChildOfHelper(View v)`
`void`	`loadParameters( ConstraintSet.Constraint constraint, HelperWidget child, ConstraintLayout.LayoutParams layoutParams, SparseArray<ConstraintWidget> mapIdToWidget )` Load the parameters
`void`	`onDraw(@NonNull Canvas canvas)`
`int`	`removeView(View view)` 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`	`updatePostConstraints(ConstraintLayout container)` update after constraints are resolved
`void`	`updatePostLayout(ConstraintLayout container)` Allows a helper a chance to update its internal object post layout or set up connections for the pointed elements
`void`	`updatePostMeasure(ConstraintLayout container)`
`void`	`updatePreDraw(ConstraintLayout container)` called before the draw
`void`	`updatePreLayout(ConstraintLayout container)` 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`	`validateParams()` Allows a helper to replace the default ConstraintWidget in LayoutParams by its own subclass

Protected methods
`void`	`applyLayoutFeatures()`
`void`	`applyLayoutFeatures(ConstraintLayout container)`
`void`	`applyLayoutFeaturesInConstraintSet(ConstraintLayout container)`
`View[]`	`getViews(ConstraintLayout layout)`
`void`	`init(AttributeSet attrs)`
`void`	`onAttachedToWindow()`
`void`	`onMeasure(int widthMeasureSpec, int heightMeasureSpec)`
`void`	`setIds(String idList)`
`void`	`setReferenceTags(String tagList)`

Inherited Constants

From android.view.View

`static final int`	`ACCESSIBILITY_DATA_SENSITIVE_AUTO = 0`
`static final int`	`ACCESSIBILITY_DATA_SENSITIVE_NO = 2`
`static final int`	`ACCESSIBILITY_DATA_SENSITIVE_YES = 1`
`static final int`	`ACCESSIBILITY_LIVE_REGION_ASSERTIVE = 2`
`static final int`	`ACCESSIBILITY_LIVE_REGION_NONE = 0`
`static final int`	`ACCESSIBILITY_LIVE_REGION_POLITE = 1`
`static final Property<View, Float>`	`ALPHA`
`static final int`	`AUTOFILL_FLAG_INCLUDE_NOT_IMPORTANT_VIEWS = 1`
`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`	`AUTOFILL_HINT_CREDIT_CARD_NUMBER = "creditCardNumber"`
`static final String`	`AUTOFILL_HINT_CREDIT_CARD_SECURITY_CODE = "creditCardSecurityCode"`
`static final String`	`AUTOFILL_HINT_EMAIL_ADDRESS = "emailAddress"`
`static final String`	`AUTOFILL_HINT_NAME = "name"`
`static final String`	`AUTOFILL_HINT_PASSWORD = "password"`
`static final String`	`AUTOFILL_HINT_PHONE = "phone"`
`static final String`	`AUTOFILL_HINT_POSTAL_ADDRESS = "postalAddress"`
`static final String`	`AUTOFILL_HINT_POSTAL_CODE = "postalCode"`
`static final String`	`AUTOFILL_HINT_USERNAME = "username"`
`static final int`	`AUTOFILL_TYPE_DATE = 4`
`static final int`	`AUTOFILL_TYPE_LIST = 3`
`static final int`	`AUTOFILL_TYPE_NONE = 0`
`static final int`	`AUTOFILL_TYPE_TEXT = 1`
`static final int`	`AUTOFILL_TYPE_TOGGLE = 2`
`static final int`	`CONTENT_SENSITIVITY_AUTO = 0`
`static final int`	`CONTENT_SENSITIVITY_NOT_SENSITIVE = 2`
`static final int`	`CONTENT_SENSITIVITY_SENSITIVE = 1`
`static final int`	`DRAG_FLAG_ACCESSIBILITY_ACTION = 1024`
`static final int`	`DRAG_FLAG_GLOBAL = 256`
`static final int`	`DRAG_FLAG_GLOBAL_PERSISTABLE_URI_PERMISSION = 64`
`static final int`	`DRAG_FLAG_GLOBAL_PREFIX_URI_PERMISSION = 128`
`static final int`	`DRAG_FLAG_GLOBAL_SAME_APPLICATION = 4096`
`static final int`	`DRAG_FLAG_GLOBAL_URI_READ = 1`
`static final int`	`DRAG_FLAG_GLOBAL_URI_WRITE = 2`
`static final int`	`DRAG_FLAG_OPAQUE = 512`
`static final int`	`DRAG_FLAG_START_INTENT_SENDER_ON_UNHANDLED_DRAG = 8192`
`static final int`	`DRAWING_CACHE_QUALITY_AUTO = 0` This field is deprecated.
`static final int`	`DRAWING_CACHE_QUALITY_HIGH = 1048576` This field is deprecated.
`static final int`	`DRAWING_CACHE_QUALITY_LOW = 524288` This field is deprecated.
`static final int[]`	`EMPTY_STATE_SET`
`static final int[]`	`ENABLED_FOCUSED_SELECTED_STATE_SET`
`static final int[]`	`ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`ENABLED_FOCUSED_STATE_SET`
`static final int[]`	`ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`ENABLED_SELECTED_STATE_SET`
`static final int[]`	`ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`ENABLED_STATE_SET`
`static final int[]`	`ENABLED_WINDOW_FOCUSED_STATE_SET`
`static final int`	`FIND_VIEWS_WITH_CONTENT_DESCRIPTION = 2`
`static final int`	`FIND_VIEWS_WITH_TEXT = 1`
`static final int`	`FOCUSABLE = 1`
`static final int`	`FOCUSABLES_ALL = 0`
`static final int`	`FOCUSABLES_TOUCH_MODE = 1`
`static final int`	`FOCUSABLE_AUTO = 16`
`static final int[]`	`FOCUSED_SELECTED_STATE_SET`
`static final int[]`	`FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`FOCUSED_STATE_SET`
`static final int[]`	`FOCUSED_WINDOW_FOCUSED_STATE_SET`
`static final int`	`FOCUS_BACKWARD = 1`
`static final int`	`FOCUS_DOWN = 130`
`static final int`	`FOCUS_FORWARD = 2`
`static final int`	`FOCUS_LEFT = 17`
`static final int`	`FOCUS_RIGHT = 66`
`static final int`	`FOCUS_UP = 33`
`static final int`	`GONE = 8`
`static final int`	`HAPTIC_FEEDBACK_ENABLED = 268435456`
`static final int`	`IMPORTANT_FOR_ACCESSIBILITY_AUTO = 0`
`static final int`	`IMPORTANT_FOR_ACCESSIBILITY_NO = 2`
`static final int`	`IMPORTANT_FOR_ACCESSIBILITY_NO_HIDE_DESCENDANTS = 4`
`static final int`	`IMPORTANT_FOR_ACCESSIBILITY_YES = 1`
`static final int`	`IMPORTANT_FOR_AUTOFILL_AUTO = 0`
`static final int`	`IMPORTANT_FOR_AUTOFILL_NO = 2`
`static final int`	`IMPORTANT_FOR_AUTOFILL_NO_EXCLUDE_DESCENDANTS = 8`
`static final int`	`IMPORTANT_FOR_AUTOFILL_YES = 1`
`static final int`	`IMPORTANT_FOR_AUTOFILL_YES_EXCLUDE_DESCENDANTS = 4`
`static final int`	`IMPORTANT_FOR_CONTENT_CAPTURE_AUTO = 0`
`static final int`	`IMPORTANT_FOR_CONTENT_CAPTURE_NO = 2`
`static final int`	`IMPORTANT_FOR_CONTENT_CAPTURE_NO_EXCLUDE_DESCENDANTS = 8`
`static final int`	`IMPORTANT_FOR_CONTENT_CAPTURE_YES = 1`
`static final int`	`IMPORTANT_FOR_CONTENT_CAPTURE_YES_EXCLUDE_DESCENDANTS = 4`
`static final int`	`INVISIBLE = 4`
`static final int`	`KEEP_SCREEN_ON = 67108864`
`static final int`	`LAYER_TYPE_HARDWARE = 2`
`static final int`	`LAYER_TYPE_NONE = 0`
`static final int`	`LAYER_TYPE_SOFTWARE = 1`
`static final int`	`LAYOUT_DIRECTION_INHERIT = 2`
`static final int`	`LAYOUT_DIRECTION_LOCALE = 3`
`static final int`	`LAYOUT_DIRECTION_LTR = 0`
`static final int`	`LAYOUT_DIRECTION_RTL = 1`
`static final int`	`MEASURED_HEIGHT_STATE_SHIFT = 16`
`static final int`	`MEASURED_SIZE_MASK = 16777215`
`static final int`	`MEASURED_STATE_MASK = -16777216`
`static final int`	`MEASURED_STATE_TOO_SMALL = 16777216`
`static final int`	`NOT_FOCUSABLE = 0`
`static final int`	`NO_ID = -1`
`static final int`	`OVER_SCROLL_ALWAYS = 0`
`static final int`	`OVER_SCROLL_IF_CONTENT_SCROLLS = 1`
`static final int`	`OVER_SCROLL_NEVER = 2`
`static final int[]`	`PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_SELECTED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_FOCUSED_SELECTED_STATE_SET`
`static final int[]`	`PRESSED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_FOCUSED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_SELECTED_STATE_SET`
`static final int[]`	`PRESSED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_STATE_SET`
`static final int[]`	`PRESSED_WINDOW_FOCUSED_STATE_SET`
`static final float`	`REQUESTED_FRAME_RATE_CATEGORY_DEFAULT`
`static final float`	`REQUESTED_FRAME_RATE_CATEGORY_HIGH = -4.0f`
`static final float`	`REQUESTED_FRAME_RATE_CATEGORY_LOW = -2.0f`
`static final float`	`REQUESTED_FRAME_RATE_CATEGORY_NORMAL = -3.0f`
`static final float`	`REQUESTED_FRAME_RATE_CATEGORY_NO_PREFERENCE = -1.0f`
`static final Property<View, Float>`	`ROTATION`
`static final Property<View, Float>`	`ROTATION_X`
`static final Property<View, Float>`	`ROTATION_Y`
`static final Property<View, Float>`	`SCALE_X`
`static final Property<View, Float>`	`SCALE_Y`
`static final int`	`SCREEN_STATE_OFF = 0`
`static final int`	`SCREEN_STATE_ON = 1`
`static final int`	`SCROLLBARS_INSIDE_INSET = 16777216`
`static final int`	`SCROLLBARS_INSIDE_OVERLAY = 0`
`static final int`	`SCROLLBARS_OUTSIDE_INSET = 50331648`
`static final int`	`SCROLLBARS_OUTSIDE_OVERLAY = 33554432`
`static final int`	`SCROLLBAR_POSITION_DEFAULT = 0`
`static final int`	`SCROLLBAR_POSITION_LEFT = 1`
`static final int`	`SCROLLBAR_POSITION_RIGHT = 2`
`static final int`	`SCROLL_AXIS_HORIZONTAL = 1`
`static final int`	`SCROLL_AXIS_NONE = 0`
`static final int`	`SCROLL_AXIS_VERTICAL = 2`
`static final int`	`SCROLL_CAPTURE_HINT_AUTO = 0`
`static final int`	`SCROLL_CAPTURE_HINT_EXCLUDE = 1`
`static final int`	`SCROLL_CAPTURE_HINT_EXCLUDE_DESCENDANTS = 4`
`static final int`	`SCROLL_CAPTURE_HINT_INCLUDE = 2`
`static final int`	`SCROLL_INDICATOR_BOTTOM = 2`
`static final int`	`SCROLL_INDICATOR_END = 32`
`static final int`	`SCROLL_INDICATOR_LEFT = 4`
`static final int`	`SCROLL_INDICATOR_RIGHT = 8`
`static final int`	`SCROLL_INDICATOR_START = 16`
`static final int`	`SCROLL_INDICATOR_TOP = 1`
`static final int[]`	`SELECTED_STATE_SET`
`static final int[]`	`SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int`	`SOUND_EFFECTS_ENABLED = 134217728`
`static final int`	`STATUS_BAR_HIDDEN = 1` This field is deprecated.
`static final int`	`STATUS_BAR_VISIBLE = 0` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_FULLSCREEN = 4` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_HIDE_NAVIGATION = 2` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_IMMERSIVE = 2048` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_IMMERSIVE_STICKY = 4096` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN = 1024` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION = 512` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LAYOUT_STABLE = 256` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR = 16` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LIGHT_STATUS_BAR = 8192` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LOW_PROFILE = 1` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_VISIBLE = 0` This field is deprecated.
`static final int`	`SYSTEM_UI_LAYOUT_FLAGS = 1536` This field is deprecated.
`static final int`	`TEXT_ALIGNMENT_CENTER = 4`
`static final int`	`TEXT_ALIGNMENT_GRAVITY = 1`
`static final int`	`TEXT_ALIGNMENT_INHERIT = 0`
`static final int`	`TEXT_ALIGNMENT_TEXT_END = 3`
`static final int`	`TEXT_ALIGNMENT_TEXT_START = 2`
`static final int`	`TEXT_ALIGNMENT_VIEW_END = 6`
`static final int`	`TEXT_ALIGNMENT_VIEW_START = 5`
`static final int`	`TEXT_DIRECTION_ANY_RTL = 2`
`static final int`	`TEXT_DIRECTION_FIRST_STRONG = 1`
`static final int`	`TEXT_DIRECTION_FIRST_STRONG_LTR = 6`
`static final int`	`TEXT_DIRECTION_FIRST_STRONG_RTL = 7`
`static final int`	`TEXT_DIRECTION_INHERIT = 0`
`static final int`	`TEXT_DIRECTION_LOCALE = 5`
`static final int`	`TEXT_DIRECTION_LTR = 3`
`static final int`	`TEXT_DIRECTION_RTL = 4`
`static final Property<View, Float>`	`TRANSLATION_X`
`static final Property<View, Float>`	`TRANSLATION_Y`
`static final Property<View, Float>`	`TRANSLATION_Z`
`static final String`	`VIEW_LOG_TAG = "View"`
`static final int`	`VISIBLE = 0`
`static final int[]`	`WINDOW_FOCUSED_STATE_SET`
`static final Property<View, Float>`	`X`
`static final Property<View, Float>`	`Y`
`static final Property<View, Float>`	`Z`

Inherited methods

From android.view.View

`void`	`addChildrenForAccessibility(ArrayList<View> outChildren)`
`void`	`addExtraDataToAccessibilityNodeInfo( AccessibilityNodeInfo info, String extraDataKey, Bundle arguments )`
`void`	`addFocusables(ArrayList<View> views, int direction)`
`void`	`addKeyboardNavigationClusters(Collection<View> views, int direction)`
`void`	`addOnAttachStateChangeListener( View.OnAttachStateChangeListener listener )`
`void`	`addOnLayoutChangeListener(View.OnLayoutChangeListener listener)`
`void`	`addOnUnhandledKeyEventListener( View.OnUnhandledKeyEventListener listener )`
`void`	`addTouchables(ArrayList<View> views)`
`ViewPropertyAnimator`	`animate()`
`void`	`announceForAccessibility(CharSequence text)`
`void`	`autofill(AutofillValue value)`
`boolean`	`awakenScrollBars()`
`void`	`bringToFront()`
`void`	`buildDrawingCache()` This method is deprecated.
`void`	`buildLayer()`
`boolean`	`callOnClick()`
`boolean`	`canResolveLayoutDirection()`
`boolean`	`canResolveTextAlignment()`
`boolean`	`canResolveTextDirection()`
`boolean`	`canScrollHorizontally(int direction)`
`boolean`	`canScrollVertically(int direction)`
`final void`	`cancelDragAndDrop()`
`void`	`cancelLongPress()`
`final void`	`cancelPendingInputEvents()`
`boolean`	`checkInputConnectionProxy(View view)`
`void`	`clearAnimation()`
`void`	`clearFocus()`
`void`	`clearPendingCredentialRequest()`
`void`	`clearViewTranslationCallback()`
`static int`	`combineMeasuredStates(int curState, int newState)`
`int`	`computeHorizontalScrollExtent()`
`int`	`computeHorizontalScrollOffset()`
`int`	`computeHorizontalScrollRange()`
`void`	`computeScroll()`
`WindowInsets`	`computeSystemWindowInsets(WindowInsets in, Rect outLocalInsets)`
`int`	`computeVerticalScrollExtent()`
`int`	`computeVerticalScrollOffset()`
`int`	`computeVerticalScrollRange()`
`AccessibilityNodeInfo`	`createAccessibilityNodeInfo()`
`void`	`createContextMenu(ContextMenu menu)`
`void`	`destroyDrawingCache()` This method is deprecated.
`WindowInsets`	`dispatchApplyWindowInsets(WindowInsets insets)`
`boolean`	`dispatchCapturedPointerEvent(MotionEvent event)`
`void`	`dispatchConfigurationChanged(Configuration newConfig)`
`void`	`dispatchCreateViewTranslationRequest( Map<AutofillId, long[]> viewIds, int[] supportedFormats, TranslationCapability capability, List<ViewTranslationRequest> requests )`
`void`	`dispatchDisplayHint(int hint)`
`boolean`	`dispatchDragEvent(DragEvent event)`
`void`	`dispatchDraw(Canvas canvas)`
`void`	`dispatchDrawableHotspotChanged(`

ConstraintHelper

Summary

Constants

Protected fields

Public constructors

Public methods

Protected methods

Inherited Constants

Inherited methods