2D sprite animator for Unity

SpriteAnimator.cs

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

[RequireComponent (typeof(SpriteRenderer))]
public class SpriteAnimator : MonoBehaviour
{
	public List<Sprite> frames = new List<Sprite> ();
	public float fps = 15;
	public bool playOnStart;
	public bool loop;

	SpriteRenderer rend;
	int currentFrame;
	float playStartTime;

	public bool IsPlaying { get; private set; }

	void Awake ()
	{
		rend = GetComponent<SpriteRenderer> ();
	}

	void Start ()
	{
		if (playOnStart) {
			Play ();
		}
	}

	public void Play ()
	{
		if (frames.Count == 0) {
			return;
		}
		StartCoroutine ("DoPlay");
	}

	IEnumerator DoPlay ()
	{
		IsPlaying = true;
		playStartTime = Time.time;
		currentFrame = 0;
		while (true) {
			if (fps < 1) {
				yield return null;
			}
			var t = (Time.time - playStartTime) * fps;
			if (loop || (!loop && t < frames.Count)) {
				SetFrame (Mathf.FloorToInt (t));
			}
			yield return null;
		}
	}

	public void Stop ()
	{
		IsPlaying = false;
		SetFrame (0);
		StopAllCoroutines ();
		playStartTime = 0;
	}

	public void SetFrame (int frame)
	{
		currentFrame = frame % frames.Count;
		rend.sprite = frames[currentFrame];
	}
}

SpriteAnimatorEditor.cs

using UnityEngine;
using UnityEditor;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

[CustomEditor (typeof(SpriteAnimator))]
public class SpriteAnimatorEditor : Editor
{
	// Example code:
	// https://gist.github.com/bzgeb/3800350

	SerializedObject obj;
	
	void OnEnable ()
	{
		obj = new SerializedObject (target);
	}

	public override void OnInspectorGUI ()
	{
		DrawDefaultInspector ();
		EditorGUILayout.Space ();
		if (GUILayout.Button ("Sort Frames")) {
			((SpriteAnimator)obj.targetObject).frames = ((SpriteAnimator)obj.targetObject).frames.OrderBy (s => s.name).ToList ();
		}
		DropAreaGUI ();
	}

	public void DropAreaGUI ()
	{
		Event evt = Event.current;
		Rect dropArea = GUILayoutUtility.GetRect (0.0f, 50.0f, GUILayout.ExpandWidth (true));
		GUI.Box (dropArea, "Add Sprites");
		
		switch (evt.type) {
		case EventType.DragUpdated:
		case EventType.DragPerform:
			if (!dropArea.Contains (evt.mousePosition)) {
				return;
			}
			
			DragAndDrop.visualMode = DragAndDropVisualMode.Copy;
			
			if (evt.type == EventType.DragPerform) {
				DragAndDrop.AcceptDrag ();

				foreach (Object draggedObject in DragAndDrop.objectReferences) {
					if (draggedObject is Sprite) {
						// Add sprites to list directly
						((SpriteAnimator)obj.targetObject).frames.Add ((Sprite)draggedObject);
					} else if (draggedObject is Texture) {
						// Grab all sprites associated with a texture, add to list
						var path = AssetDatabase.GetAssetPath (draggedObject);
						var assets = AssetDatabase.LoadAllAssetRepresentationsAtPath (path);
						foreach (var subAsset in assets) {
							if (subAsset is Sprite) {
								((SpriteAnimator)obj.targetObject).frames.Add ((Sprite)subAsset);
							}
						}
					}
				}
			}
			break;
		}
	}
}