How to scroll to a specific element in ScrollRect with Unity UI?

Question

I built a registration form for a mobile game using Unity 5.1. To do that, I use Unity UI components: ScrollRect + Autolayout (Vertical layout) + Text (labels)

Answer 1

The preconditions for my version of this problem:

• The element I want to scroll to should be fully visible (with minimal clearance)
• The element is a direct child of the scrollRect's content
• Keep scoll position if element is already fully visible
• I only care about the vertical dimension

This is what worked best for me (thanks for the other inspirations):

// ScrollRect scrollRect;
// RectTransform element;
// Fully show `element` inside `scrollRect` with at least 25px clearance
scrollArea.EnsureVisibility(element, 25);

Using this extension method:

public static void EnsureVisibility(this ScrollRect scrollRect, RectTransform child, float padding=0)
{
    Debug.Assert(child.parent == scrollRect.content,
        "EnsureVisibility assumes that 'child' is directly nested in the content of 'scrollRect'");

    float viewportHeight = scrollRect.viewport.rect.height;
    Vector2 scrollPosition = scrollRect.content.anchoredPosition;

    float elementTop = child.anchoredPosition.y;
    float elementBottom = elementTop - child.rect.height;

    float visibleContentTop = -scrollPosition.y - padding;
    float visibleContentBottom = -scrollPosition.y - viewportHeight + padding;

    float scrollDelta =
        elementTop > visibleContentTop ? visibleContentTop - elementTop :
        elementBottom < visibleContentBottom ? visibleContentBottom - elementBottom :
        0f;

    scrollPosition.y += scrollDelta;
    scrollRect.content.anchoredPosition = scrollPosition;
}