Screen Size

Detecting changes to the screen size is very common for many different use cases in games. The UI Toolkit package includes the singleton ScreenSizeListener that allows you to register a callback to know when the screen size changes.

ScreenSizeListener.Instance.resized += OnResize;

private void OnResize(float width, float height)
    // handle resize here

You can simply get the current screen size too. There seems to be a bug with Unity's Screen.width and Screen.height because they do not always return the correct values. Using the listener can be more reliable.

if (ScreenSizeListener.HasInstance)
    // Individual properties
    float width = ScreenSizeListener.Instance.width;
    float height = ScreenSizeListener.Instance.height;

    // Single property
    Vector2Int size = ScreenSizeListener.Instance.size;