public static void NavigateBack()
{
if (!PlatformServices.BackStackEnabled)
{
return;
}
StackItem?stackResult = null;
// screens are added when moving to a new screen, while states are added as you move
if (mBackStack.Current.HasValue && !string.IsNullOrEmpty(mBackStack.Current.Value.Screen))
{
stackResult = mBackStack.Current.Value;
mBackStack.Back();
}
else
{
stackResult = mBackStack.Back();
}
if (!stackResult.HasValue)
{
// if we've gone to the beginning of the back stack, we should exit the game
FlatRedBallServices.Game.Exit();
return;
}
StackItem stackItem = stackResult.Value;
if (!string.IsNullOrEmpty(stackItem.Screen))
{
mCurrentScreen.NextScreen = stackItem.Screen;
mCurrentScreen.IsActivityFinished = true;
mCurrentScreen.IsMovingBack = true;
}
else if (stackItem.State > -1)
{
// states are set as they are moved to, so if this is the last state, we should exit
if (mBackStack.Count == 0)
{
FlatRedBallServices.Game.Exit();
return;
}
mCurrentScreen.MoveToState(stackItem.State);
}
}