public Constraint Update(ConstraintOffsetTarget offset)
{
_constant = offset;
return(this);
}
public Constraint(ConstraintItem from, ConstraintItem to, ConstraintRelation relation, Tuple <string, uint> sourceLocation, ConstraintMultiplierTarget multiplier, ConstraintConstantTarget constant, ConstraintPriorityTarget priority, string label = null)
{
_to = to;
_from = from;
_relation = relation;
_constant = constant;
_priority = priority;
_multiplier = multiplier;
_constraints = new List <LayoutConstraint>();
Label = label;
SourceLocation = sourceLocation;
var layoutFrom = _from.LayoutConstraintItem;
var layoutRelation = _relation.LayoutRelation();
var layoutToAttributes = _to.Attributes.LayoutAttributes();
var layoutFromAttributes = _from.Attributes.LayoutAttributes();
foreach (var layoutFromAttribute in layoutFromAttributes)
{
var layoutToAttribute = default(NSLayoutAttribute);
if (layoutToAttributes?.Length > 0)
{
if (_from.Attributes == ConstraintAttributes.Edges &&
_to.Attributes == ConstraintAttributes.Margins)
{
switch (layoutFromAttribute)
{
case NSLayoutAttribute.Top:
layoutToAttribute = NSLayoutAttribute.TopMargin;
break;
case NSLayoutAttribute.Left:
layoutToAttribute = NSLayoutAttribute.LeftMargin;
break;
case NSLayoutAttribute.Bottom:
layoutToAttribute = NSLayoutAttribute.BottomMargin;
break;
case NSLayoutAttribute.Right:
layoutToAttribute = NSLayoutAttribute.RightMargin;
break;
default:
throw new InvalidOperationException();
}
}
else if (_from.Attributes == ConstraintAttributes.Margins &&
_to.Attributes == ConstraintAttributes.Edges)
{
switch (layoutFromAttribute)
{
case NSLayoutAttribute.TopMargin:
layoutToAttribute = NSLayoutAttribute.Top;
break;
case NSLayoutAttribute.LeftMargin:
layoutToAttribute = NSLayoutAttribute.Left;
break;
case NSLayoutAttribute.BottomMargin:
layoutToAttribute = NSLayoutAttribute.Bottom;
break;
case NSLayoutAttribute.RightMargin:
layoutToAttribute = NSLayoutAttribute.Right;
break;
default:
throw new InvalidOperationException();
}
}
else if (_from.Attributes == _to.Attributes)
{
layoutToAttribute = layoutFromAttribute;
}
else
{
layoutToAttribute = layoutToAttributes[0];
}
}
else
{
if (_to.Target == null && (layoutFromAttribute == NSLayoutAttribute.CenterX || layoutFromAttribute == NSLayoutAttribute.CenterY))
{
layoutToAttribute = ((layoutFromAttribute == NSLayoutAttribute.CenterX) ? NSLayoutAttribute.Left : NSLayoutAttribute.Top);
}
else
{
layoutToAttribute = layoutFromAttribute;
}
}
var layoutConstant = _constant.ValueForAttribute(layoutToAttribute);
var layoutTo = _to.Target;
if (layoutTo == null &&
layoutToAttribute != NSLayoutAttribute.Width &&
layoutToAttribute != NSLayoutAttribute.Height)
{
layoutTo = layoutFrom.Superview;
}
// Create layout constraint
var layoutConstraint = new LayoutConstraint(
layoutFrom,
layoutFromAttribute,
layoutRelation,
(UIView)layoutTo,
layoutToAttribute,
_multiplier,
layoutConstant
);
// Set label
layoutConstraint.Label = Label;
// Set priority
layoutConstraint.Priority = _priority;
// Set constraint
layoutConstraint.Constraint = this;
// Append
_constraints.Add(layoutConstraint);
}
}
public Constraint Update(ConstraintInsetTarget inset)
{
_constant = inset.TargetValue;
return(this);
}