Add a float to a list in a foreach statement

Code (csharp):

1.  
2.         foreach (Transform Target in PossibleTartgets)
3.         {
4.             Debug.Log(Target + " | " + Vector2.Distance(transform.position, Target.position));
5.             TargetDistance.Add(Vector2.Distance(transform.position, Target.position));
6.         }
7.  

When I run this I get this error:

NullReferenceException: Object reference not set to an instance of an object
simpleEnemy.SetTarget () (at Assets/scripts/enemies/simpleEnemy.cs:26)
simpleEnemy.Awake () (at Assets/scripts/enemies/simpleEnemy.cs:18)

 

I think it could be a bug, but I'm not sure and I wouldn't know how to solve it if i was.

 

Could you add the full script? Hard to debug if we don't know the correct line numbers.

Just from looking what you have posted I guess "PossibleTartgets", any of the "Target"s, or TargetDistance could be null / uninitialized.

 

Code (csharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using System.Linq;
5. using UnityEngine;
6. public class simpleEnemy : MonoBehaviour
7. {
8.     [Header("Target")]
9.     public List<Transform> PossibleTartgets;
10.     private List<float> TargetDistance;
11.     public Transform target;
12.     public float speed;
13.     private void Awake()
14.     {
15.         SetTarget();
16.     }
17.     void SetTarget()
18.     {
19.         foreach (Transform Target in PossibleTartgets)
20.         {
21.             Debug.Log(Target + " | " + Vector2.Distance(transform.position, Target.position));
22.             TargetDistance.Add(Vector2.Distance(transform.position, Target.position));
23.         }
24.         float SumTargetDistance = TargetDistance.Sum();
25.         float RandomTarget = Random.Range(0, SumTargetDistance);
26.         for (int Targets = 0; Targets < PossibleTartgets.Capacity; Targets++)
27.         {
28.             if (TargetDistance[Targets - 1] < RandomTarget && RandomTarget > TargetDistance[Targets])
29.             {
30.                 target = PossibleTartgets[Targets];
31.             }
32.         }
33.     }
34.     public void FixedUpdate()
35.     {
36.         transform.position = Vector2.MoveTowards(transform.position, target.position, speed * Time.deltaTime);
37.     }
38. }
39.  

 

From that code, AdamRamberg was correct -- you made a novice mistake by not setting up the TargetDistance list. Nothing to do with the foreach.

PossibleTartgets is magic, since it's in the Inspector. Unity sets it up for you, filling it with tarts. But everything else in normal and works the normal programming way.

 

Then how would I fix it (I don't really know what you mean by that)

 

Simply set it up in Awake, before you call the other method.

Code (csharp):

1. private void Awake()
2. {
3.     TargetDistance = new List<float>();
4.     // ...
5. }

I'd also recommend to useTargetDistances.

 

Well, maybe. But then SetTarget would need to clear the list (they'll eventually call it more than once, right?) I feel like it was supposed to be Local. But then I'm seeing several other problems: a -1 index error in the "select target based on weighted distance", and Capacity for Count, and it doesn't appear to work anyway; FixedUpdate. I feel like this is someone over their head, possibly grabbed some things from tutorials that weren't quite right to begin with. Maybe should start with something easier.

 

Yes, you're right. Just wanted to throw in the solution to the first problem that you identified though.