I want to be able to position my child view 25% the size of the super view from the top.
NSLayoutConstraint *topPositionConstraint = [NSLayoutConstraint constraintWithItem:_containerView
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:_childView
attribute:NSLayoutAttributeHeight
multiplier:0.25f
constant:0.0f];
However, right now I'm getting the following exception:
'NSInvalidArgumentException', reason: '*** +[NSLayoutConstraint constraintWithItem:attribute:relatedBy:toItem:attribute:multiplier:constant:]: Invalid pairing of layout attributes'
Why does the error occur and how can I achieve what I want?