SpriteAnimation.cs

using UnityEngine;
using System.Collections;

[System.Serializable]
public class Animation
{
    public string name;
    public float delay;
    public Texture2D[] textures;
    public bool loop;

    [HideInInspector]
    public int frame;

    public void NextFrame()
    {
        frame++;

        if (frame >= textures.Length)
        {
            if (loop)
            {
                frame = 0;
            }
            else
            {
                frame = textures.Length - 1;
            }
        }
    }
}

public class SpriteAnimation : MonoBehaviour
{
    public Animation[] animations;

    public float speed = 1f;

    public bool isPlaying { get; private set; }
    public float timer { get; private set; }

    private Animation currentAnimation;

    public void Play(string name)
    {
        Animation animation = GetAnimation(name);
        if (animation != null)
        {
            currentAnimation = animation;
            currentAnimation.frame = 0;
            isPlaying = true;
            timer = 0f;
            SetCurrentFrame();
        }
    }

    public Animation GetAnimation(string name)
    {
        foreach (Animation animation in animations)
        {
            if (animation.name == name)
                return animation;
        }
        return null;
    }

    void SetCurrentFrame()
    {
        if (currentAnimation != null)
        {
            renderer.material.mainTexture = currentAnimation.textures[currentAnimation.frame];
        }
    }

    void Update()
    {
        if (isPlaying)
        {
            if (currentAnimation != null)
            {
                timer += Time.deltaTime * speed;

                while (timer > currentAnimation.delay)
                {
                    currentAnimation.NextFrame();
                    timer -= currentAnimation.delay;
                }

                SetCurrentFrame();
            }
        }
    }
}