Visualizing State Machines with Custom Inspectors

In this lesson, you will learn how to create a custom Inspector window that provides a real-time, visual dashboard for monitoring your state machine’s active state and transition history.

Bridging Logic and Visibility

When building complex state machines, debugging abstract transitions via the Console can be tedious. By extending the Unity Editor, we can create a "live view" that reflects exactly what your State Machine is doing during Play Mode. Instead of digging through code, you’ll see the current state name and potential exit paths displayed clearly in the Inspector.

Implementing the Custom Editor

To achieve this, we create a script in an Editor folder that targets your StateMachineController. By overriding the OnInspectorGUI() method, we can draw custom UI elements. We specifically want to access the currentState property of our controller to update the UI every frame.

[CustomEditor(typeof(StateMachineController))]
public class StateMachineEditor : Editor
{
    public override void OnInspectorGUI()
    {
        base.OnInspectorGUI(); // Show default fields
        
        StateMachineController controller = (StateMachineController)target;

        if (Application.isPlaying)
        {
            EditorGUILayout.Space();
            EditorGUILayout.HelpBox("Active State: " + controller.CurrentStateName, MessageType.Info);
            
            // Visualize transition history or available exits
            EditorGUILayout.LabelField("Available Exits", EditorStyles.boldLabel);
            foreach (var transition in controller.CurrentStateExits)
            {
                EditorGUILayout.LabelField("- " + transition.TargetStateName);
            }
        }
    }
}

Why This Matters

By utilizing OnInspectorGUI and checking Application.isPlaying, you gain a diagnostic tool that works specifically when your logic is active. This setup transforms your Inspector from a static data container into a dynamic debugging console. You aren't just reading variables; you are observing the "brain" of your game architecture as it processes logic. This visual feedback loop significantly reduces the time spent hunting for bugs in state transitions, as you can instantly verify if your machine is stuck in an incorrect state or failing to trigger an expected exit condition.

Key Takeaway: Custom Inspectors turn invisible state logic into a real-time diagnostic dashboard, allowing you to monitor active states and transitions without leaving the Editor.