androidx.constraintlayout.core.widgets

Class ConstraintAnchor

java.lang.Object

androidx.constraintlayout.core.widgets.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.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ConstraintAnchor.Type Define the type of anchor

Field Summary

Fields

Modifier and Type	Field and Description
int	mMargin
ConstraintWidget	mOwner
ConstraintAnchor	mTarget
ConstraintAnchor.Type	mType

Constructor Summary

Constructors

Constructor and Description
ConstraintAnchor(ConstraintWidget owner, ConstraintAnchor.Type type) Constructor

Method Summary

Modifier and Type	Method and Description
boolean	connect(ConstraintAnchor toAnchor, int margin) Connects this anchor to another one.
boolean	connect(ConstraintAnchor toAnchor, int margin, int goneMargin, boolean forceConnection) Connects this anchor to another one.
void	copyFrom(ConstraintAnchor source, java.util.HashMap<ConstraintWidget,ConstraintWidget> map)
void	findDependents(int orientation, java.util.ArrayList<WidgetGroup> list, WidgetGroup group)
java.util.HashSet<ConstraintAnchor>	getDependents()
int	getFinalValue()
int	getMargin() Return the connection's margin from this anchor to its target.
ConstraintAnchor	getOpposite() Returns the opposite anchor to this one
ConstraintWidget	getOwner() Return the anchor's owner
SolverVariable	getSolverVariable() Return the solver variable for this anchor
ConstraintAnchor	getTarget() Return the connection's target (null if not connected)
ConstraintAnchor.Type	getType() Return the type of the anchor
boolean	hasCenteredDependents()
boolean	hasDependents()
boolean	hasFinalValue()
boolean	isConnected() Returns the connection status of this anchor
boolean	isConnectionAllowed(ConstraintWidget target) Return true if we can connect this anchor to this target.
boolean	isConnectionAllowed(ConstraintWidget target, ConstraintAnchor anchor) Return true if we can connect this anchor to this target.
boolean	isSideAnchor() Return true if this anchor is a side anchor
boolean	isSimilarDimensionConnection(ConstraintAnchor anchor) Return true if the connection to the given anchor is in the same dimension (horizontal or vertical)
boolean	isValidConnection(ConstraintAnchor anchor) Checks if the connection to a given anchor is valid.
boolean	isVerticalAnchor() Utility function returning true if this anchor is a vertical one.
void	reset() Resets the anchor's connection.
void	resetFinalResolution()
void	resetSolverVariable(Cache cache) Reset the solver variable
void	setFinalValue(int finalValue)
void	setGoneMargin(int margin) Set the gone margin of the connection (if there's one)
void	setMargin(int margin) Set the margin of the connection (if there's one)
java.lang.String	toString() Return a string representation of this anchor

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

mOwner

public final ConstraintWidget mOwner

mType

public final ConstraintAnchor.Type mType

mTarget

public ConstraintAnchor mTarget

mMargin

public int mMargin

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)

getDependents

public java.util.HashSet<ConstraintAnchor> getDependents()

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()

copyFrom

public void copyFrom(ConstraintAnchor source,
                     java.util.HashMap<ConstraintWidget,ConstraintWidget> map)

getSolverVariable

public SolverVariable getSolverVariable()

Return the solver variable for this anchor

Returns:

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.

Parameters:

toAnchor -

margin -

goneMargin -

forceConnection -

Returns:

true if the connection succeeds.

connect

public boolean connect(ConstraintAnchor toAnchor,
                       int margin)

Connects this anchor to another one.

Parameters:

toAnchor -

margin -

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