Is reference better than UnityEvent ?

Question

Actually, I have a UI which updates every time. I want to make it updating only when a player's attribute (like HP) changes. So, I would like to know what is better: give the UI as parameter to a script or just link the UI modification script to an UnityEvent ?

Answer 1

It's much better to not connect UI with update (so using a reference).

Connecting UI with events is much much better, both in terms of performance and encapsulation.

Let me show you also a trick using properties.

 public class Health : MonoBehaviour
 {
     //I'm using Actions because they're (said to) be more performant than  UnityEvents, but they are much the same
     public Action <int> OnHealthChange;
 
     //track and update health with a property
     private int _currentHP;
     public int CurrentHP
     {
         get => _currentHP;
         private set
         {
             _currentHP = value;
             OnHealthChange?.Invoke(value);
         }

         //if you use a property you can be sure that the event will alwaye be called when you change the current hit points
         private void SufferDamage(int damage) => CurrentHP -= damage;
         private void Heal(int amount) => CurrentHP += amount;
     }
 }
 
 public class HealthUI : MonoBehaviour
 {
     public Health _health;
 
     private void ShowHealth(int currentHealth)
     {
         //show health here, in sliders or tect
     }
     
     //start and stop tracking on enable
     private void OnEnable()
     {
         ShowHealth(_health.CurrentHP);
         _health.OnHealthChange += ShowHealth;
     }
     private void OnDisable() { _health.OnHealthChange -= ShowHealth; }
 }

Further reading: Difference between UnityEvent and Actions

Is reference better than UnityEvent ?

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