showlocalrotationhandles.cs

    
    // This method allows us to add a ShowLocalAxis component to the currently selected transform.
    // We'll be using a toggle box to add or remove the component. This bool holds that state.
    private bool showLoxalAxisToggle = false;
    // This holds a reference to the ShowLocalAxis component.
    private ShowLocalAxis showLocalAxis;
    private void ShowLocalAxisComponentToggle()
    {    
        // First we check to see if there is a ShowLocalAxis component on this game object.
        showLocalAxis = _transform.gameObject.GetComponent<ShowLocalAxis>();

        // If not we can set the toggle to false which will remove the tick mark.
        if (showLocalAxis == null)
            showLoxalAxisToggle = false;
        else  // If the ShowLocalAxis component exists then ensure the toggle is set true.
            showLoxalAxisToggle = true;

        // Here we're going to use a Horizontal layout which allows us to put the elements on a single line.
        EditorGUILayout.BeginHorizontal();
        
        // Put in our label field
        EditorGUILayout.LabelField("Show local rotation handles", EditorStyles.boldLabel);
        
        // Start monitoring the inspector for change in the showLocalAxisToggle value.
        EditorGUI.BeginChangeCheck();
        
        // Display and set the toggle's value. 
        // In the label for this I am using a ternary operator which to decide what label to display.
        // This is shorthand for saying: if showLocalAxisToggle is true then display "on" otherwise display "off".
        showLoxalAxisToggle = EditorGUILayout.ToggleLeft((showLoxalAxisToggle ? "on" : "off" ), showLoxalAxisToggle);
        
        // We can now stop monitoring for changes and IF a change has occurred then we add or remove the component.
        if (EditorGUI.EndChangeCheck())
        {
            // If we've toggle ON the component then add it.
            if (showLoxalAxisToggle == true)
            {
                // Add the component
                showLocalAxis = _transform.gameObject.AddComponent<ShowLocalAxis>();
                
                // Now we're going to move that component up right underneath the transform component.
                // First we get the total number of components on the game object.
                int componentCount = _transform.GetComponents<Component>().Length;
                
                // Then we move the component up 1 less times than the number of components since the
                // first compoent is the Transform component.
                for (int i = 1; i < componentCount; i++)
                {
                    UnityEditorInternal.ComponentUtility.MoveComponentUp(showLocalAxis);
                }
            }
            else
            {
                // If we've toggle OFF the toggle then mark the component so that
                // it can be destroyed at the proper time. This is handled in the 
                // ShowLocalAxisInspector class.
                showLocalAxis.destroyWhenSafe = true;
            }
        }
        
        // Finally we can end our horizontal layout so the next GUI element is on a new line.
        EditorGUILayout.EndHorizontal();
    }