/// <summary>
/// Exits the current <see cref="IScreen"/>.
/// </summary>
/// <param name="source">The <see cref="IScreen"/> which last exited.</param>
/// <param name="onExiting">An action that is invoked when the current screen allows the exit to continue.</param>
private void exitFrom([CanBeNull] IScreen source, Action onExiting = null)
{
// The current screen is at the top of the stack, it will be the one that is exited
var toExit = stack.Pop();
// The next current screen will be resumed
if (toExit.OnExiting(CurrentScreen))
{
stack.Push(toExit);
return;
}
// we will probably want to change this logic when we support returning to a screen after exiting.
toExit.ValidForResume = false;
toExit.ValidForPush = false;
onExiting?.Invoke();
if (source == null)
{
// This is the first screen that exited
toExit.AsDrawable().Expire();
}
else
{
// This screen exited via a recursive-exit chain. Lifetime is propagated from the parent.
toExit.AsDrawable().LifetimeEnd = ((Drawable)source).LifetimeEnd;
}
ScreenExited?.Invoke(toExit, CurrentScreen);
// Resume the next current screen from the exited one
resumeFrom(toExit);
}
private bool exitFrom([CanBeNull] IScreen source, bool shouldFireExitEvent = true, bool shouldFireResumeEvent = true, IScreen destination = null)
{
if (stack.Count == 0)
{
return(false);
}
// The current screen is at the top of the stack, it will be the one that is exited
var toExit = stack.Pop();
// The next current screen will be resumed
if (shouldFireExitEvent && toExit.AsDrawable().IsLoaded)
{
var next = CurrentScreen;
// Add the screen back on the stack to allow pushing screens in OnExiting.
stack.Push(toExit);
// if a screen is !ValidForResume, it should not be allowed to block unless it is the current screen (source == null)
// OnExiting should still be called regardless.
bool blockRequested = toExit.OnExiting(new ScreenExitEvent(toExit, next, destination ?? next));
if ((source == null || toExit.ValidForResume) && blockRequested)
{
return(true);
}
stack.Pop();
}
// we will probably want to change this logic when we support returning to a screen after exiting.
toExit.ValidForResume = false;
toExit.ValidForPush = false;
if (source == null)
{
// This is the first screen that exited
toExit.AsDrawable().Expire();
}
exited.Add(toExit.AsDrawable());
log($"exit from {getTypeString(toExit)}");
log($"resume to {getTypeString(CurrentScreen)}");
ScreenExited?.Invoke(toExit, CurrentScreen);
// Resume the next current screen from the exited one
if (shouldFireResumeEvent)
{
resumeFrom(toExit);
}
return(false);
}
/// <summary>
/// Exits the current <see cref="IScreen"/>.
/// </summary>
/// <param name="source">The <see cref="IScreen"/> which last exited.</param>
/// <param name="onExiting">An action that is invoked when the current screen allows the exit to continue.</param>
/// <param name="shouldFireExitEvent">Whether <see cref="IScreen.OnExiting"/> should be fired on the exiting screen.</param>
/// <param name="shouldFireResumeEvent">Whether <see cref="IScreen.OnResuming"/> should be fired on the resuming screen.</param>
private void exitFrom([CanBeNull] IScreen source, Action onExiting = null, bool shouldFireExitEvent = true, bool shouldFireResumeEvent = true)
{
if (stack.Count == 0)
{
return;
}
// The current screen is at the top of the stack, it will be the one that is exited
var toExit = stack.Pop();
// The next current screen will be resumed
if (shouldFireExitEvent && toExit.AsDrawable().IsLoaded&& toExit.OnExiting(CurrentScreen))
{
// If the exit event gets cancelled, add the screen back on the stack.
stack.Push(toExit);
return;
}
// we will probably want to change this logic when we support returning to a screen after exiting.
toExit.ValidForResume = false;
toExit.ValidForPush = false;
onExiting?.Invoke();
if (source == null)
{
// This is the first screen that exited
toExit.AsDrawable().Expire();
}
exited.Add(toExit.AsDrawable());
ScreenExited?.Invoke(toExit, CurrentScreen);
// Resume the next current screen from the exited one
if (shouldFireResumeEvent)
{
resumeFrom(toExit);
}
}