/// <summary>
/// Draws a Drag and Drop Area and allows you to send in a method which receives an array of the objects that were dragged into the area.
/// <para></para>
/// The caller method needs to receive a generic type "T" and then cast it to its desired type itself OR use a Lambda Expression for handling the OnDragged-event.
/// <para></para>
/// Example implementation in OnGUI: '<see cref="Paalo.UnityMiscTools.Examples.DragAndDropAreaExample"/>'
/// </summary>
/// <seealso cref="HowToDrawDragAndDropArea"/>
/// <typeparam name="T">The object type you want the '<paramref name="OnPerformedDragCallback"/>'-method to handle.</typeparam>
/// <param name="dragAreaInfo">How the DragArea should look like and what text it should display.</param>
/// <returns></returns>
public static void DrawDragAndDropArea <T>(DragAndDropAreaInfo dragAreaInfo, System.Action <T[]> OnPerformedDragCallback = null) where T : UnityEngine.Object
{
//Change color and create Drag Area
Color originalGUIColor = GUI.color;
GUI.color = dragAreaInfo.outlineColor;
EditorGUILayout.BeginVertical(GUI.skin.box);
GUI.color = dragAreaInfo.backgroundColor;
var dragArea = GUILayoutUtility.GetRect(dragAreaInfo.dragAreaWidth, dragAreaInfo.dragAreaHeight, GUILayout.ExpandWidth(true));
GUI.Box(dragArea, dragAreaInfo.DragAreaText);
//See if the current Editor Event is a DragAndDrop event.
var anEvent = Event.current;
switch (anEvent.type)
{
case EventType.DragUpdated:
case EventType.DragPerform:
if (!dragArea.Contains(anEvent.mousePosition))
{
//Early Out in case the drop is made outside the drag area.
break;
}
//Change mouse cursor icon to the "Copy" icon
DragAndDrop.visualMode = DragAndDropVisualMode.Copy;
//If mouse is released
if (anEvent.type == EventType.DragPerform)
{
DragAndDrop.AcceptDrag();
var draggedTypeObjectsArray = GetDraggedObjects <T>();
OnPerformedDragCallback?.Invoke(draggedTypeObjectsArray);
}
Event.current.Use();
break;
}
EditorGUILayout.EndVertical();
GUI.color = originalGUIColor;
}
private void GUISection_GetAudioClips()
{
Color oldGuiColor = GUI.color;
EditorGUILayout.BeginVertical(GUI.skin.box);
EditorGUILayout.Space();
var dragAndDropInfo = new DragAndDropAreaInfo("Audio Clips", Color.black, Color.cyan);
PaaloEditorHelper.DrawDragAndDropArea <AudioClip>(dragAndDropInfo, UpdateAudioClipsOnDragAndDrop);
EditorGUILayout.Space();
GUI.color = Color.red;
if (GUILayout.Button("Clear selected AudioClips"))
{
//audioClips = null;
audioClips = new AudioClip[0];
}
EditorGUILayout.Space();
GUI.color = oldGuiColor;
EditorGUILayout.EndVertical();
}