Focusable.Focus

Description

Attempt to give the focus to this element.

The element may not become focused if:

• The element cannot be focused. See Focusable.canGrabFocus.
• The element delegates its focus. See Focusable.delegatesFocus.

A Panel's current focused element can be retrieved using its FocusController's focusedElement property.

As long as an element is focused, it receives all keyboard and navigation events sent to its Panel.

If a focus change is requested during another event's propagation, the change is only applied after all the events currently in the event queue have been fully dispatched and propagated.

Additional resources: Focusable.canGrabFocus, Focusable.delegatesFocus, IFocusRing, FocusController.focusedElement

using UnityEngine;
using UnityEngine.UIElements;

[RequireComponent(typeof(UIDocument))]
public class FocusExample : MonoBehaviour
{
    void OnEnable()
    {
        var startGameButton = GetComponent<UIDocument>().rootVisualElement.Q<Button>("StartGame");

        startGameButton.RegisterCallback<FocusInEvent>(ev =>
        {
            Debug.Log("FocusInEvent: button is focused and can be activated with keyboard or gamepad input.");
        });

        Debug.Log("Calling startGameButton.Focus().");
        startGameButton.Focus();

        var isFocused = startGameButton.focusController.focusedElement == startGameButton;
        Debug.Log("Immediately after startGameButton.Focus(): isFocused=" + isFocused);

        // Expected output:
        // > Calling startGameButton.Focus().
        // > FocusInEvent: button is focused and can be activated with keyboard or gamepad input.
        // > Immediately after startGameButton.Focus(): isFocused=true
    }
}