public static void TriggerEvent(string eventName, ItemButton itemButton)
{
CustomEventWithItemButtonParameter thisEvent = null;
if (Instance.eventDictionary.TryGetValue(eventName, out thisEvent))
{
thisEvent.Invoke(itemButton);
}
}
// We must take care of memory leaks, and unsubscribe.
public static void StopListening(string eventName, UnityAction <ItemButton> listener)
{
// If there is no eventManager in scene, we have nothing to worry about, and just leave method.
if (eventManager == null)
{
return;
}
CustomEventWithItemButtonParameter thisEvent = null;
if (Instance.eventDictionary.TryGetValue(eventName, out thisEvent))
{
thisEvent.RemoveListener(listener);
}
}
public static void StartListening(string eventName, UnityAction <ItemButton> listener)
{
CustomEventWithItemButtonParameter thisEvent = null;
// Pass by reference copies an argument's memory address into the formal parameter.
// Inside the method, the address is used to access the actual argument used in the call.
// This means that changes made to the parameter affect the argument.
// Output parameters are similar to reference parameters, except that they transfer data out of the method rather than accept data in.
// They are defined using the out keyword.
// The variable supplied for the output parameter need not be initialized since that value will not be used.
// Output parameters are particularly useful when you need to return multiple values from a method.
// TryGetValue https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.dictionary-2.trygetvalue?view=netframework-4.7.2
// Gets the value associated with the specified key.
// public bool TryGetValue(TKey key, out TValue value);
// key TKey
// The key of the value to get.
// value TValue
// When this method returns, contains the value associated with the specified key, if the key is found;
// otherwise, the default value for the type of the value parameter. This parameter is passed uninitialized.
// Returns Boolean
// true if the Dictionary<TKey,TValue> contains an element with the specified key; otherwise, false.
// So here we will check if there is an event with eventName in the dictionary
if (Instance.eventDictionary.TryGetValue(eventName, out thisEvent))
// If there is already an event with such name, we just add listener to original event.
// It is possible due to using out keyword
{
thisEvent.AddListener(listener);
}
else
// ..and if there is no such event in dictionary, we`ll create one, also add listener, just as in true case,
// and finally put this new event to Dictionary.
{
thisEvent = new CustomEventWithItemButtonParameter();
thisEvent.AddListener(listener);
Instance.eventDictionary.Add(eventName, thisEvent);
}
}
