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Awake function issues in relation to Singleton

So I was looking into implementing the new Unity input system into my game by reworking my code in my PlayerController script and got stuck pretty early on.
Here is the code that causes issues:
private PlayerInput playerInputController;
private void Awake()
{
playerInputController = new PlayerInput();
}
A green scribbly line appears under the 'Awake()' bit.
The code itself actually works, but it causes a lof of other issues, which makes a bunch of error messages appear saying:
NullReferenceException: Object reference not set to an instance of an object
The error messages all lead to places where I've used lines of code like this one in other scripts, to get variables and methods from my PlayerController script:
if (PlayerController.instance.isGroundedPhys)
Lastly, here's my singleton script, since it's likely relevant, as it's connected to my PlayerController script and allows it to be accessible from other scripts:
using UnityEngine;
public class Singleton<Instance> : MonoBehaviour where Instance : Singleton<Instance>
{
public static Instance instance;
public virtual void Awake()
{
if (!instance)
{
instance = this as Instance;
}
else
{
Destroy(gameObject);
}
}
}
This bit is at the top of my PlayerController script to make it accessible from other scripts:
public class PlayerController : Singleton<PlayerController>
{
I've been looking around and can't find anybody talking about similar issues. I think it's related to my singleton script, but I can't figure it out. :[
[Edit]:
I just found out it also gives this warning in the Unity console:
warning CS0114: 'PlayerController.Awake()' hides inherited member 'Singleton<PlayerController>.Awake()'. To make the current member override that implementation, add the override keyword. Otherwise add the new keyword.

PlayerInput is a MonoBehaviour!
No seriously, this is "Not Allowed" and you should actually give you an according warning in the console.
A MonoBehaviour "can"/should only exist attached to an according GameObject and always be created by the underlying c++ framework. It's a c# thing that Unity can't fully prevent you from using new to create one.
The only valid way of creating an instance of a MonoBehaviour are
Instantiate a prefab that has the component attached
use AddComponent on an existing GameObject
use the constructor of GameObject and pass in the according component type(s)
Or you probably rather want to use e.g. GetComponent or FindObjectOfType in order to get a reference to an already existing instance of PlayerInput.
And then the other warning means you implemented
public void Awake()
{
// ...
}
or similar in your PlayerController class. The warning already tells you exactly what to rather do:
// Use "override" in order to not hide the already existing implementation
// of "Awake" in the base class
public override void Awake()
{
// Make sure the base class behavior is executed
// this will initialize the Singleton thing
base.Awake();
// ... your additional behavior here
}

private/public Field is not seen in inspector when I use GridLayoutGroup in unity

private/public Field is not seen in inspector when i using GridLayoutGroup
here is the example
This is how I am defining my variables:
using System.Collections;
using System.Collections.Generic;
using UnityEngine.UI;
using UnityEngine;
using UnityEditor;
public class Myscript : GridLayoutGroup
{
[SerializeField] private bool ishhh;
}

Most Unity built-in components have an according [CustomEditor] overwriting the default Inspector.
In specific the GridLayoutGroup has a custom inspector called GridLayoutGroupEditor overwriting the inspector for any class derived from GridLayoutGroup.
→ You have to inherit from it in order to make a custom editor for a class derived from GridLayoutGroup.
In order to make additional fields visible you could do something like e.g.
using UnityEditor;
...
[CustomEditor(typeof(Myscript))]
public class MyScriptEditor : GridLayoutGroupEditor
{
private SerializedProperty ishhh;
// Called when the Inspector is loaded
// Usually when the according GameObject gets selected in the hierarchy
private void OnEnable ()
{
// "Link" the SerializedProperty to a real serialized field
// (public fields are serialized automatically)
ishhh = serializedObject.FindProperty("ishhh");
}
// Kind of the Inspector's Update method
public override void OnInpectorGUI ()
{
// Draw the default inspector
// base.OnInspectorGUI();
// Fetch current values into the serialized properties
serializedObject.Update();
// Automatically uses the correct field drawer according to the property type
EditorGUILayout.PropertyField(ishhh);
// Write back changed values to the real component
serializedObject.ApplyModifiedProperties();
}
}
Important: Place this script in a folder called Editor so it is stripped of in a build to avoid built-errors regarding the UnityEditor namespace.
Alternatively (since I can see that you already have a using UnityEditor in your example code) you can leave it in the same script but then you have to manually use #if Pre-Processors in order to strip all code-blocks/-lines off that use something from the UnityEditor namespace like
#if UNITY_EDITOR
using UnityEditor;
#endif
...
#if UNITY_EDITOR
// any code using UnityEditor
#endif
Otherwise you won't be able to build your app since the UnityEditor only exists in the Unity Editor itself and is completely stripped off for builds.
Note: Typed on smartphone so no warranty but I hope the idea gets clear

Object Reference Not Set to an Instance - Unity2D

I have this simple code to change the sprite of an image everytime I click a button.
using UnityEngine;
using UnityEngine.UI;
public class SampleChange : MonoBehaviour {
public Sprite sampleSprite;
public Image sampleImage;
public void Start()
{
sampleImage = GetComponent<Image>();
}
public void changeColor()
{
sampleImage.gameObject.GetComponent<Image>();
sampleImage.sprite = sampleSprite;
}
}
I attached this script to an EmptyGameObject and Loaded the function on the Button that is parented on a Canvas alongside the Image. I already also placed the Image and Sprite objects in the inspector:
Inspector Settings
When I run the game and click the Button, it gives me this error:
NullReferenceException: Object reference not set to an instance of an object
SampleChange.changeColor () (at Assets/Scripts/SampleChange.cs:18)
The cs:18 is the sampleImage.sprite = sampleSprite;. I really don't know why it's not working.

OK simple,
public Image sampleImage;
that means
you will set "sampleImage" variable in the inspector, in the editor, before you hit Play
But this one ..
sampleImage = GetComponent<Image>();
means
you will set "sampleImage" variable in code when the scene is running.
You have to sort it out and do it "one way or the other".
Suggest you use the first method while U learning.
(If you do use the second method, the "Image" must actually be on the game object which is holding the script in question. If you struggle with that, I would urge you to ask a separate question, or just study up on the basics using Unity tutorials.)
Cheers

It appears that you have no constuctor defined for your class and that you are just trying to call the changeColor() method as if it were a static function of the class. You need to construct objects of your class and then call the methods you defined on those objects, not on the class itself.

How to set different classes at runtime in Unity

I am making a game in Unity C# where the character will have different characterstics and movement functions in each scene. So I am trying to have different scripts for a player in different scenes, while all of them inheriting from the same base class. The definition will be something like below
public class PlayerScript1 : PlayerBase { /* for scene 1*/
public void Move(){
/* my movement code*/
}
}
Similarly, I have a separate class for Scene2 as
public class PlayerScript2 : PlayerBase { /* for scene 2*/
public void Move(){
/* my movement code*/
}
}
Now the problem is, my other scripts, like HealthScript,ScoreScript etc they do not change with scene. But they do access PlayerScript1 script. And thats why, I have the PlayerScript1 declaration in them. Like below:
public class HealthScript : MonoBehaviour {
PlayerScript1 playerScript;
void Start(){
/*accessing the script attached to game object*/
}
}
So how can I have my Health Script access different instances of my PlayerScript based on the scene? I know I could use delegates to call different methods in runtime, but how can I do the same with classes?

So how can I have my Health Script access different instances of my PlayerScript based on the scene?
Well first, you'll want to declare that object as of Type PlayerBase as you will be unable to assign an instance of PlayerScript2 to a variable of type PlayerScript1: those classes might inherit from the same parent, but they are not the same and you cannot convert from one to the other.
After that you will need to search for the player object in the scene, something like...
void Start(){
playerScript = GameObject.Find("Player").GetComponent<PlayerBase>();
}
Assuming, of course, that PlayerBase extends MonoBehaviour. If it doesn't you can't get a reference this way (as it won't exist in the scene at all). Additionally if you want this health object to persist from scene to scene, you need to call DontDestroyOnLoad() for it (as well as remembering that if you don't start testing from Scene 1 where this object is, it won't exist at all, or if you have a copy in every scene, you'll have duplication problems).

Someone answered to my question on the Unity forum which cleared all my doubts:
The key was using the below line in my HealthScript :
PlayerBase player = (PlayerBase)FindObjectOfType(typeof(PlayerBase));
http://answers.unity3d.com/answers/1348311/view.html

GameObject creation order issue

I'm currently working on an inventory system in Unity3D, and came upon a weird problem. I have created non-MonoBehaviour classes for my inventory system (in case that matters), so that I have an Inventory class which holds a list of Slot objects, which in turn holds a list of Item objects.
Then I added a component script to my "HudInventoryPanel", called "HudInventoryController", which looks like this:
using UnityEngine;
using System.Collections;
public class HudSlotController : MonoBehaviour {
private InventoryController ic;
// Use this for initialization
void Start () {
ic = GetComponent<InventoryController>();
}
// Update is called once per frame
void Update () {
}
}
However, inside the Start() method, the InventoryController (part of my Player) hasn't been created yet, and it seems to me like the gameobjects are created in alphabetical order...?
How should I deal with this problem?

You can specify script execution order in the project settings (Edit -> Project settings -> Script execution order), so use that to make sure your scripts are executed in the correct order. In addition to that, you can use the Awake() method as all Awakes are executed before any Start() method. Hope a combination of these helps you!

I solved this by creating an intermediate variable in my InventoryController script, plus creating a "manual" getter; https://gist.github.com/toreau/f7110f0eb266c3c12f1b
Not sure why I have to do it this way, though.