【Unity】矢印キーで2Dプレイヤーを1マスずつ移動

if (Input.GetKey(KeyCode.RightArrow))
{
    // →キーが押されている間、毎フレーム実行される
}

// 知らせる側
public event Action<Vector3> MoveRequested;   // Vector3（方向）を一緒に渡すイベント
MoveRequested?.Invoke(Vector3.up);            // 登録されている処理をまとめて呼ぶ

// 受け取る側
input.MoveRequested += OnMoveRequested;       // 登録
input.MoveRequested -= OnMoveRequested;       // 解除

playerRenderer.sprite = spriteUp;   // 上向きの画像に切り替える

using System;
using System.Collections.Generic;
using UnityEngine;

/// <summary>
/// 矢印キーから移動の要求
/// </summary>
public class PlayerInput : MonoBehaviour
{
    [SerializeField] private float repeatDelay = 0.2f;     
    [SerializeField] private float repeatInterval = 0.1f;  
    private float repeatTimer;      

    public event Action<Vector3> MoveRequested; 
    public event Action Released;              
    //入力キーと方向を対応させる
    private static readonly (KeyCode key, Vector3 direction)[] bindings =
    {
        (KeyCode.UpArrow, Vector3.up),
        (KeyCode.DownArrow, Vector3.down),
        (KeyCode.RightArrow, Vector3.right),
        (KeyCode.LeftArrow, Vector3.left),
    };

    // 押された順に並べたbindingsの添字。最後が現在有効なキー
    private readonly List<int> heldKeys = new List<int>();
    private const int None = -1;  // キーを押していない
    private int CurrentIndex => heldKeys.Count > 0 ? heldKeys[heldKeys.Count - 1] : None;

    private void Update()
    {
        int previousIndex = CurrentIndex;

        heldKeys.RemoveAll(i => !Input.GetKey(bindings[i].key));
        for (int i = 0; i < bindings.Length; i++)
        {
            if (Input.GetKeyDown(bindings[i].key) && !heldKeys.Contains(i))
                heldKeys.Add(i);
        }
        
        int currentIndex = CurrentIndex;
        if (currentIndex == None)
        {
            if (previousIndex != None) Released?.Invoke();
            return;
        }

        if (currentIndex != previousIndex)
        {
            repeatTimer = repeatDelay;
            MoveRequested?.Invoke(bindings[currentIndex].direction);
            return;
        }

        repeatTimer -= Time.deltaTime;
        if (repeatTimer <= 0f)
        {
            repeatTimer = repeatInterval;
            MoveRequested?.Invoke(bindings[currentIndex].direction);
        }
    }
}

using System;
using UnityEngine;

/// <summary>
/// 対象を1マスずつ動かす。向き・移動の通知を行う
/// </summary>
public class GridMover : MonoBehaviour
{
    [SerializeField] private Transform target;
    [SerializeField] private float gridSize = 1f;

    public event Action<Vector3> MoveAttempted;
    public event Action<Vector3, Vector3> Moved;

    //移動処理
    public bool TryMove(Vector3 direction)
    {
        if (direction == Vector3.zero || target == null) return false;

        MoveAttempted?.Invoke(direction);

        Vector3 nextPos = target.position + direction * gridSize; //移動先

        target.position = nextPos;  //位置更新
        Moved?.Invoke(nextPos, direction);
        return true;
    }
}

using UnityEngine;

/// <summary>
/// プレイヤーの進行で画像差し替え
/// </summary>
public class PlayerDirectionSprite : MonoBehaviour
{
    //止まっているときの状態
    private enum IdleFacingMode
    {
        IdleSprite, //待機
        LastDirection //最後に向いている方向
    }

    [SerializeField] private SpriteRenderer playerRenderer;
    [SerializeField] private Sprite spriteIdle;
    [SerializeField] private Sprite spriteUp;
    [SerializeField] private Sprite spriteDown;
    [SerializeField] private Sprite spriteLeft;
    [SerializeField] private Sprite spriteRight;
    [SerializeField] private IdleFacingMode idleFacingMode = IdleFacingMode.LastDirection;

    private Vector3 lastFacingDirection = Vector3.zero;

    //指定した方向を向く
    public void Face(Vector3 direction)
    {
        if (direction == Vector3.zero) return; 

        lastFacingDirection = direction;
        SetSprite(GetSpriteForDirection(direction));
    }

    //止まったときの画像にする
    public void ShowIdle()
    {
        bool hasLastFacing = lastFacingDirection != Vector3.zero;
        bool keepLastFacing = idleFacingMode == IdleFacingMode.LastDirection && hasLastFacing;

        SetSprite(keepLastFacing ? GetSpriteForDirection(lastFacingDirection) : null);
    }

    //画像の差し替え
    private void SetSprite(Sprite sprite)
    {
        if (playerRenderer == null) return;

        Sprite nextSprite = sprite ?? spriteIdle;
        if (nextSprite != null && playerRenderer.sprite != nextSprite)
            playerRenderer.sprite = nextSprite;
    }

    //対応する画像を呼び出す
    private Sprite GetSpriteForDirection(Vector3 direction)
    {
        if (direction == Vector3.up && spriteUp != null) return spriteUp;
        if (direction == Vector3.down && spriteDown != null) return spriteDown;
        if (direction == Vector3.left && spriteLeft != null) return spriteLeft;
        if (direction == Vector3.right && spriteRight != null) return spriteRight;
    
        return null;
    }
}

using UnityEngine;

/// <summary>
/// シーン開始時のプレイヤーの位置と向きを決める
/// </summary>
public class PlayerSpawner : MonoBehaviour
{
    [SerializeField] private Transform target;
    [SerializeField] private Vector3 startPosition = new Vector3(0.5f, 0.5f, 0f); 

    // 開始位置に置き、開始時の向きを startFacing に入れる
    public void Spawn(out Vector3 startFacing)
    {
        if (target == null) target = transform;

        target.position = startPosition;
        startFacing = Vector3.zero;
    }
}

using UnityEngine;

/// <summary>
/// プレイヤーの各コンポーネントの接続
/// 入力 → 移動 → 向きの画像
/// </summary>
public class PlayerController : MonoBehaviour
{
    [SerializeField] private PlayerInput input;
    [SerializeField] private GridMover mover;
    [SerializeField] private PlayerSpawner spawner;
    [SerializeField] private PlayerDirectionSprite directionSprite; // 向きスプライト制御

    // イベントの登録/解除
    private void OnEnable()
    {
        if (input != null)
        {
            input.MoveRequested += OnMoveRequested; 
            input.Released += OnReleased;
        }
        if (mover != null)
        {
            mover.MoveAttempted += OnMoveAttempted;
        }
    }

    private void OnDisable()
    {
        if (input != null)
        {
            input.MoveRequested -= OnMoveRequested;
            input.Released -= OnReleased;
        }
        if (mover != null)
        {
            mover.MoveAttempted -= OnMoveAttempted;
        }
    }

    private void Start()
    {
        Vector3 startFacing = Vector3.zero;
        if (spawner != null) spawner.Spawn(out startFacing);

        if (directionSprite == null) return;
        if (startFacing == Vector3.zero) directionSprite.ShowIdle();
        else directionSprite.Face(startFacing);
    }

    ///イベントを受け取る
    private void OnMoveRequested(Vector3 direction) => mover?.TryMove(direction);
    private void OnReleased() => directionSprite?.ShowIdle();
    private void OnMoveAttempted(Vector3 direction) => directionSprite?.Face(direction);
}

[PlayerInput] 矢印キーを押す → MoveRequested
      ↓
[PlayerController] OnMoveRequested → GridMover.TryMove()
      ↓
[GridMover] MoveAttempted → 1マス移動 → Moved
      ↓
[PlayerController] OnMoveAttempted → PlayerDirectionSprite.Face()（画像を切り替え）

[PlayerInput] キーを離す → Released → PlayerDirectionSprite.ShowIdle()

// 有効なキーが変わった：即移動
if (currentIndex != previousIndex)
{
    repeatTimer = repeatDelay;
    MoveRequested?.Invoke(bindings[currentIndex].direction);
    return;
}

//同じキーを押し続ける
repeatTimer -= Time.deltaTime;
if (repeatTimer <= 0f)
{
    repeatTimer = repeatInterval;
    MoveRequested?.Invoke(bindings[currentIndex].direction);
}

//リスト更新（離されたキーを外し、新しく押されたキーを末尾に追加）
heldKeys.RemoveAll(i => !Input.GetKey(bindings[i].key));
for (int i = 0; i < bindings.Length; i++)
{
    if (Input.GetKeyDown(bindings[i].key) && !heldKeys.Contains(i))
        heldKeys.Add(i);
}

private int CurrentIndex => heldKeys.Count > 0 ? heldKeys[heldKeys.Count - 1] : None;