【Unity】NullReferenceException: Object reference not set to an instance of an object の解決方を教えてください。

Error
1NullReferenceException: Object reference not set to an instance of an object
2TarodevController.PlayerController.OnEnable () (at Assets/Scripts/Player/PlayerController.cs:52)

が出て実行できません。

エラーが出るコード

C#
1using System.Collections.Generic;
2using System.Linq;
3using UnityEngine;
4using UnityEngine.InputSystem;
5
6namespace TarodevController {
7    public class PlayerController : MonoBehaviour, IPlayerController {
8        // Public for external hooks
9        public Vector3 Velocity { get; private set; }
10        public FrameInput Input { get; private set; }
11        public bool JumpingThisFrame { get; private set; }
12        public bool LandingThisFrame { get; private set; }
13        public Vector3 RawMovement { get; private set; }
14        public bool Grounded => _colDown;
15
16        private Vector3 _lastPosition;
17        private float _currentHorizontalSpeed, _currentVerticalSpeed;
18
19        private PlayerInput input;
20        private bool jump;
21        private Vector2 movement;
22
23        // This is horrible, but for some reason colliders are not fully established when update starts...
24        private bool _active;
25        void Awake() => Invoke(nameof(Activate), 0.5f);
26        void Activate() =>  _active = true;
27
28        void Start()
29        {
30            input = GetComponent<PlayerInput>();
31        }
32
33        private void Update() {
34            if(!_active) return;
35            // Calculate velocity
36            Velocity = (transform.position - _lastPosition) / Time.deltaTime;
37            _lastPosition = transform.position;
38
39            GatherInput();
40            RunCollisionChecks();
41
42            CalculateWalk(); // Horizontal movement
43            CalculateJumpApex(); // Affects fall speed, so calculate before gravity
44            CalculateGravity(); // Vertical movement
45            CalculateJump(); // Possibly overrides vertical
46
47            MoveCharacter(); // Actually perform the axis movement
48        }
49/////////////////////////////////////////////////////////////////////////////////////////////////////////
50    void OnEnable()
51    {
52        input.actions["Move"].performed += OnMove;
53        input.actions["Move"].canceled += OnMove;
54
55        input.actions["Jump"].performed += OnJump;
56        input.actions["Jump"].canceled += OnJump;
57    }
58/////////////////////////////////////////////////////////////////////////////////////////////////////////
59    void OnDisable()
60    {
61        input.actions["Move"].performed -= OnMoveStop;
62        input.actions["Move"].canceled -= OnMoveStop;
63
64        input.actions["Jump"].performed -= OnJump;
65        input.actions["Jump"].canceled -= OnJump;
66    }
67
68    private void OnJump(InputAction.CallbackContext obj)
69    {
70        switch(obj.phase)
71        {
72            case InputActionPhase.Performed:
73                jump = true;
74                break;
75            case InputActionPhase.Canceled:
76                jump = false;
77                break;
78        }
79    }
80
81    private void OnMove(InputAction.CallbackContext obj)
82    {
83        movement = obj.ReadValue<Vector2>();
84    }
85
86    private void OnMoveStop(InputAction.CallbackContext obj)
87    {
88        movement = Vector2.zero;
89    }
90
91        #region Gather Input
92
93        private void GatherInput() {
94            Input = new FrameInput {
95                JumpDown = jump, JumpUp = jump, X = movement.x
96            };
97            if (Input.JumpDown) {
98                _lastJumpPressed = Time.time;
99            }
100        }
101
102        #endregion
103
104        #region Collisions
105
106        [Header("COLLISION")] [SerializeField] private Bounds _characterBounds;
107        [SerializeField] private LayerMask _groundLayer;
108        [SerializeField] private int _detectorCount = 3;
109        [SerializeField] private float _detectionRayLength = 0.1f;
110        [SerializeField] [Range(0.1f, 0.3f)] private float _rayBuffer = 0.1f; // Prevents side detectors hitting the ground
111
112        private RayRange _raysUp, _raysRight, _raysDown, _raysLeft;
113        private bool _colUp, _colRight, _colDown, _colLeft;
114
115        private float _timeLeftGrounded;
116
117        // We use these raycast checks for pre-collision information
118        private void RunCollisionChecks() {
119            // Generate ray ranges. 
120            CalculateRayRanged();
121
122            // Ground
123            LandingThisFrame = false;
124            var groundedCheck = RunDetection(_raysDown);
125            if (_colDown && !groundedCheck) _timeLeftGrounded = Time.time; // Only trigger when first leaving
126            else if (!_colDown && groundedCheck) {
127                _coyoteUsable = true; // Only trigger when first touching
128                LandingThisFrame = true;
129            }
130
131            _colDown = groundedCheck;
132
133            // The rest
134~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
135　　　　　　　　　　　　　　　　　　　　　　　　　　省略
136~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
137
138                positionToMoveTo = posToTry;
139            }
140        }
141
142        #endregion
143    }
144}

出来れば早めにお願いします。┏(_ _)┓

回答2件

エラーメッセージの読み方を覚えると良いと思います。

(at Assets/Scripts/Player/PlayerController.cs:52)

これは、PlayerController.csの52行目でエラーが発生している事を表しています。

52行目↓

cs
1input.actions["Move"].performed += OnMove;

エラーメッセージNullReferenceExceptionから、「おそらく変数inputがnullになっているんだろうな」という推測が立つので、inputに代入しているコードに注目します。

cs
1void Start()
2{
3    input = GetComponent<PlayerInput>();
4}

Unityのイベント関数は Awake → OnEnable → Start の順に呼ばれるので、inputに値が代入される前にOnEnableが呼ばれているのが原因です。StartをAwakeに変更すると解決するはずです。
参考↓
【Unity検証】AwakeとStartとOnEnableの呼ばれ方を調べてみた

投稿2022/06/26 12:24