restrict a view inside the superview

Use clipsToBounds method or CGRectContainsRect

youSuperView.clipsToBounds = YES;

I think it will be helpful to you

It sounds like you want to constrain the movement of the subview (viewA) to be always completely contained by the superview (viewB). CGRectContainsRect is the right answer, but it must be applied carefully, since a subview frame is specified in it's superview's coordinate system.

// inside touches moved, compute the newViewAFrame based on the movement
// but only assign it if it meets the containment constraint:

if (CGRectContainsRect(viewB.bounds, newViewAFrame)) {
    viewA.frame = newViewAFrame;
}

Notice that we don't mention viewB.frame in the check. viewB's position in it's parent is not relevant to whether viewB contains viewA.