Package androidx.constraintlayout.core.widgets

Class ConstraintAnchor

  • public class ConstraintAnchor
extends java.lang.Object
    Model a constraint relation. Widgets contains anchors, and a constraint relation between two widgets is made by connecting one anchor to another. The anchor will contains a pointer to the target anchor if it is connected.

    • Constructor Detail

      • ConstraintAnchor

        public ConstraintAnchor​(ConstraintWidget owner,
                        ConstraintAnchor.Type type)
        Constructor
        Parameters:
        owner - the widget owner of this anchor.
        type - the anchor type.

    • Method Detail

      • findDependents

        public void findDependents​(int orientation,
                           java.util.ArrayList<WidgetGroup> list,
                           WidgetGroup group)

      • hasDependents

        public boolean hasDependents()

      • hasCenteredDependents

        public boolean hasCenteredDependents()

      • setFinalValue

        public void setFinalValue​(int finalValue)

      • getFinalValue

        public int getFinalValue()

      • resetFinalResolution

        public void resetFinalResolution()

      • hasFinalValue

        public boolean hasFinalValue()

      • getSolverVariable

        public SolverVariable getSolverVariable()
        Return the solver variable for this anchor

      • resetSolverVariable

        public void resetSolverVariable​(Cache cache)
        Reset the solver variable

      • getOwner

        public ConstraintWidget getOwner()
        Return the anchor's owner
        Returns:
        the Widget owning the anchor

      • getType

        public ConstraintAnchor.Type getType()
        Return the type of the anchor
        Returns:
        type of the anchor.

      • getMargin

        public int getMargin()
        Return the connection's margin from this anchor to its target.
        Returns:
        the margin value. 0 if not connected.

      • getTarget

        public ConstraintAnchor getTarget()
        Return the connection's target (null if not connected)
        Returns:
        the ConstraintAnchor target

      • reset

        public void reset()
        Resets the anchor's connection.

      • connect

        public boolean connect​(ConstraintAnchor toAnchor,
                       int margin,
                       int goneMargin,
                       boolean forceConnection)
        Connects this anchor to another one.
        Returns:
        true if the connection succeeds.

      • connect

        public boolean connect​(ConstraintAnchor toAnchor,
                       int margin)
        Connects this anchor to another one.
        Returns:
        true if the connection succeeds.

      • isConnected

        public boolean isConnected()
        Returns the connection status of this anchor
        Returns:
        true if the anchor is connected to another one.

      • isValidConnection

        public boolean isValidConnection​(ConstraintAnchor anchor)
        Checks if the connection to a given anchor is valid.
        Parameters:
        anchor - the anchor we want to connect to
        Returns:
        true if it's a compatible anchor

      • isSideAnchor

        public boolean isSideAnchor()
        Return true if this anchor is a side anchor
        Returns:
        true if side anchor

      • isSimilarDimensionConnection

        public boolean isSimilarDimensionConnection​(ConstraintAnchor anchor)
        Return true if the connection to the given anchor is in the same dimension (horizontal or vertical)
        Parameters:
        anchor - the anchor we want to connect to
        Returns:
        true if it's an anchor on the same dimension

      • setMargin

        public void setMargin​(int margin)
        Set the margin of the connection (if there's one)
        Parameters:
        margin - the new margin of the connection

      • setGoneMargin

        public void setGoneMargin​(int margin)
        Set the gone margin of the connection (if there's one)
        Parameters:
        margin - the new margin of the connection

      • isVerticalAnchor

        public boolean isVerticalAnchor()
        Utility function returning true if this anchor is a vertical one.
        Returns:
        true if vertical anchor, false otherwise

      • toString

        public java.lang.String toString()
        Return a string representation of this anchor
        Overrides:
        toString in class java.lang.Object
        Returns:
        string representation of the anchor

      • isConnectionAllowed

        public boolean isConnectionAllowed​(ConstraintWidget target,
                                   ConstraintAnchor anchor)
        Return true if we can connect this anchor to this target. We recursively follow connections in order to detect eventual cycles; if we do we disallow the connection. We also only allow connections to direct parent, siblings, and descendants.
        Parameters:
        target - the ConstraintWidget we are trying to connect to
        anchor - Allow anchor if it loops back to me directly
        Returns:
        if the connection is allowed, false otherwise

      • isConnectionAllowed

        public boolean isConnectionAllowed​(ConstraintWidget target)
        Return true if we can connect this anchor to this target. We recursively follow connections in order to detect eventual cycles; if we do we disallow the connection. We also only allow connections to direct parent, siblings, and descendants.
        Parameters:
        target - the ConstraintWidget we are trying to connect to
        Returns:
        true if the connection is allowed, false otherwise

      • getOpposite

        public final ConstraintAnchor getOpposite()
        Returns the opposite anchor to this one
        Returns:
        opposite anchor