/// <summary>
/// Clears the constraint's constant value.
/// </summary>
/// <param name="constraint">
/// The constraint to clear.
/// </param>
/// <param name="didCreate">
/// A value indicating whether did create.
/// </param>
public static void Clear(this NSLayoutConstraint constraint, bool didCreate)
{
if (constraint.Constant != 0)
{
NSNumber oldConstant = new NSNumber(constraint.Constant);
constraint.Constant = 0;
constraint.SetAssociatedObject(ConstantKey, oldConstant);
}
constraint.SetAssociatedObject(DidCreateKey, (NSNumber)didCreate);
}
/// <summary>
/// Restores the constraint's constant value, if it is stored as an associated object.
/// </summary>
/// <param name="constraint">
/// The constraint to restore.
/// </param>
/// <returns>
/// Returns true if the constraint was created for the purpose of collapsing the view.
/// </returns>
public static bool Restore(this NSLayoutConstraint constraint)
{
NSNumber oldConstant = (NSNumber)constraint.GetAssociatedObject(ConstantKey);
NSNumber didCreate = (NSNumber)constraint.GetAssociatedObject(DidCreateKey);
if (oldConstant != null)
{
constraint.Constant = oldConstant.FloatValue;
constraint.SetAssociatedObject(ConstantKey, null);
}
if (didCreate == null)
{
return(false);
}
constraint.SetAssociatedObject(DidCreateKey, null);
return(didCreate.BoolValue);
}