Using FSM for UI flow: Back button trouble

[modernalchemistsParticipant]

Hi!

I want to use a FSM for UI flow: Each screen is a state.
Now I also need a back button functionality.
Currently, I got a BBVar (bool) wantsBack.
Each state connects back to the “calling state” and checks if wantsBack is true.

So far so good?

My problem is:
As soon as I enter the “back state”, since wantsBack is still true, it steps back again and again and again.
I have to set wantsBack to false in every OnEnter of every state.

Is this the suggested solution?

If I use Unity states (Mechanim), there’s the concept of a Trigger, which automatically resets, once consumed.
Is there something like this in Node Canvas or am I missing something?

Thanks!

[modernalchemistsParticipant]

Short update:
One current solution would be to use this transition code:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

namespace ModernAlchemists {     [Category( "Modern Alchemists" )]     [Description( "Consumes a bool" )]     public class TransitionTrigger : ConditionTask     {         public BBParameter<bool> trigger;           protected override string info         {             get             {                 if( trigger != null                     && !trigger.isNull                     && trigger.name != "" )                 {                     return string.Format( "Trigger:" + trigger.name );                 }                 return string.Format( "Assign BBVar first." );             }         }           protected override bool OnCheck()         {             if( trigger.value )             {                 trigger.value = false;                 return true;             }             return false;         }     } }

Please note that the string info part isn’t working yet. It always prints “Trigger:”, even if the name is empty.

[GavalakisKeymaster]

Hello,

I like your solution as well as the condition 🙂 I think I will include this in the next version as well. The name property by the way, can be made easier, since BBParameter already overrides ToString(), thus to return a nice label automatically 🙂

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

namespace NodeCanvas.Tasks.Conditions{   [Category("✫ Blackboard")] [Description("Check if a boolean variable is true and if so, it is immediately reset to false.")] public class CheckBooleanTrigger : ConditionTask{   [BlackboardOnly] public BBParameter<bool> trigger;   protected override string info{ get {return string.Format("Trigger {0}", trigger);} }   protected override bool OnCheck(){ if (trigger.value){ trigger.value = false; return true; } return false; } } }

With that said though, I think that if you want to actually check if a button is clicked, then maybe using the “UGUI/Button Clicked” condition could be a better option depending on your use case.

Thanks!

[Author]

Posts