没有任何直接内置的东西可以提供UnityEngine.UI.Button或其他对象的当前按下状态。
但是您可以使用IPointerXYHandler接口来实现，例如

public class PressedState : MonoBehaviour, IPointerEnerHandler, IPointerExitHandler, IPointerDownHander, IPointerUpHandler
{
    [SerializeField] Button _button;

    public bool isPressed { get; private set; }

    public void OnPointerEnter(PointerEventData pointerEventData)
    {
        // not needed only required for handling exit
    }

    public void OnPointerExit(PointerEventData pointerEventData)
    {
        isPressed = false;
    }

    public void OnPointerDown(PointerEventData pointerEventData)
    {
        isPressed = true;
    }

    public void OnPointerUp(PointerEventData pointerEventData)
    {
        isPressed = false;
    }
}

• 在UI上，这是开箱即用的，如果您的按钮是3D碰撞器，您需要在相机上安装PhysicsRaycaster，如果是2D碰撞器，则需要安装PhyicsRaycaster2D。*

然后把这个连接到所有四个按钮上，并像这样处理它们。

public class Movement : MonoBehaviour
{
    [SerializeField] PressedState up;
    [SerializeField] PressedState down;
    [SerializeField] PressedState left;
    [SerializeField] PressedState right;
 
    void Update()
    {
        var vertical = 0;
        if(up.isPressed) vertical += 1f;
        if(down.isPressed) vertical -= 1f;
        var horizontal = 0;
        if(right.isPressed) horizontal += 1f;
        if(left.isPressed) horizontal -= 1f;

        var Vec = transform.localPosition;
        Vec.x += horizontal * Time.deltaTime * 20;
        Vec.y += vertical * Time.deltaTime * 20;
        transform.localPosition = Vec;
    }
}

确切地说，GetAxis应用了某种平滑，如果您确实需要，您可以使用Mathf.SmoothDamp等选项添加平滑
边注：一般来说，你通常希望避免更快的对角线移动，所以我可能宁愿使用

var movement = Vector2.ClampMagnitude(new Vector2(horizontal, vertical), 1f) * Time.deltaTime * 20;
transform.localPosition += movement;