//! Handle the Singleton object
void Awake()
{
if (back_button_handler == null)
{
DontDestroyOnLoad(gameObject);
back_button_handler = this;
}
else if (back_button_handler != this)
{
Destroy(gameObject);
}
}
/// <summary>
/// Registers a custom back button handler for this ViewModel.
/// </summary>
/// <param name="vm">The ViewModel.</param>
/// <param name="handle">The async handler method.</param>
/// <param name="canHandle">The optional canHandle function. When null is provided, the default behavior is applied (canHandle returns true only when the current ViewModel is active in the <see cref="ISectionsNavigator"/>).</param>
/// <param name="handlerName">The optional name of the handler. When null is provided, the ViewModel type name is used.</param>
/// <param name="priority">The optional priority. (See <see cref="IBackButtonManager.AddHandler(IBackButtonHandler, int?)"/> for more info.)</param>
public static void RegisterBackHandler(this IViewModel vm, Func <CancellationToken, Task> handle, Func <bool> canHandle = null, string handlerName = null, int?priority = null)
{
vm = vm ?? throw new ArgumentNullException(nameof(vm));
handlerName = handlerName ?? vm.GetType().Name;
handle = handle ?? throw new ArgumentNullException(nameof(handle));
canHandle = canHandle ?? DefaultCanHandle;
var backButtonManager = vm.GetService <IBackButtonManager>();
var handler = new BackButtonHandler(handlerName, canHandle, handle);
var registration = backButtonManager.RegisterHandler(handler, priority);
vm.AddDisposable("BackButtonHandler_" + handlerName, registration);
bool DefaultCanHandle()
{
var navigator = vm.GetService <ISectionsNavigator>();
// The handler can handle the back only if the associated ViewModel is the one currently active in the navigator.
return(navigator.GetActiveViewModel() == vm);
}
}
void OnEnable () {
backButton = FindObjectOfType<BackButtonHandler> ();
backButton.gameState = BackButtonHandler.GameState.Menu;
backButton.menuObject = gameObject;
}
void OnEnable () {
backButton = FindObjectOfType<BackButtonHandler> ();
backButton.gameState = BackButtonHandler.GameState.Settings;
backButton.settingsObject = gameObject;
}