Unity is not showing public methods in the event field - unity3d

Question

I have a class in Unity 2017 that only shows some of the public methods in the inspector.
using System.Collections.Generic;
using UnityEngine;
public class Inventory : MonoBehaviour
{
List<ShipPart> _inventory;
int currentInvPosition = 0;
bool invExists = false;
// Use this for initialization
void Start () {
CreateInventory(0, 0);
}
// Show all inventory parts as gameobjects
public void CreateInventory(int quality, int part)
{
...
}
void DestroyInventory()
{
...
}
public void ScrollInvLeft()
{
...
}
public void ScrollInvRight()
{
...
}
void UpdateInv(float offset)
{
...
}
public void AddInventoryItem(ShipPart newShipPart)
{
...
}
public void RemoveInventoryItem(ShipPart oldShipPart)
{
...
}
public void Test1(){}
public void Test2(int i){}
}
I thought it might be because the invisible methods have parameters, so I added the last two methods. However they are visible in the inspector!
I am trying to call the methods from a dropdown UI element, but have also tested from a button and that cant see them either.
What am I doing wrong?

Answer 1

As indicated in the official Unity tutorials, if you want to provide a function to an event in the inspector, the function must meet the following requirements:
The function must be public
The function must have a return type of void
The function must take no or one parameter
If the function takes one parameter, the latter must be one of the following types:
int
float
string
bool
UnityEngine.Object, or any type inheriting from UnityEngine.Object (such as GameObject, MonoBehaviour, ScriptableObject, ...)