// Helper function that returns a Canvas GameObject; preferably a parent of the selection, or other existing Canvas.
static public GameObject GetOrCreateCanvasGameObject()
{
GameObject selectedGo = Selection.activeGameObject;
// Try to find a gameobject that is the selected GO or one if its parents.
Canvas canvas = (selectedGo != null) ? selectedGo.GetComponentInParent <Canvas>() : null;
if (IsValidCanvas(canvas))
{
return(canvas.gameObject);
}
// No canvas in selection or its parents? Then use any valid canvas.
// We have to find all loaded Canvases, not just the ones in main scenes.
Canvas[] canvasArray = StageUtility.GetCurrentStageHandle().FindComponentsOfType <Canvas>();
for (int i = 0; i < canvasArray.Length; i++)
{
if (IsValidCanvas(canvasArray[i]))
{
return(canvasArray[i].gameObject);
}
}
// No canvas in the scene at all? Then create a new one.
return(MenuOptionsOverwrite.CreateNewUI());
}
private static void PlaceUIElementRoot(GameObject element, MenuCommand menuCommand)
{
GameObject parent = menuCommand.context as GameObject;
bool explicitParentChoice = true;
if (parent == null)
{
parent = GetOrCreateCanvasGameObject();
explicitParentChoice = false;
// If in Prefab Mode, Canvas has to be part of Prefab contents,
// otherwise use Prefab root instead.
PrefabStage prefabStage = PrefabStageUtility.GetCurrentPrefabStage();
if (prefabStage != null && !prefabStage.IsPartOfPrefabContents(parent))
{
parent = prefabStage.prefabContentsRoot;
}
}
if (parent.GetComponentInParent <Canvas>() == null)
{
// Create canvas under context GameObject,
// and make that be the parent which UI element is added under.
GameObject canvas = MenuOptionsOverwrite.CreateNewUI();
canvas.transform.SetParent(parent.transform, false);
parent = canvas;
}
// Setting the element to be a child of an element already in the scene should
// be sufficient to also move the element to that scene.
// However, it seems the element needs to be already in its destination scene when the
// RegisterCreatedObjectUndo is performed; otherwise the scene it was created in is dirtied.
SceneManager.MoveGameObjectToScene(element, parent.scene);
Undo.RegisterCreatedObjectUndo(element, "Create " + element.name);
if (element.transform.parent == null)
{
Undo.SetTransformParent(element.transform, parent.transform, "Parent " + element.name);
}
GameObjectUtility.EnsureUniqueNameForSibling(element);
// We have to fix up the undo name since the name of the object was only known after reparenting it.
Undo.SetCurrentGroupName("Create " + element.name);
GameObjectUtility.SetParentAndAlign(element, parent);
if (!explicitParentChoice) // not a context click, so center in sceneview
{
SetPositionVisibleinSceneView(parent.GetComponent <RectTransform>(), element.GetComponent <RectTransform>());
}
Selection.activeGameObject = element;
}