XiJianYCYL/Assets/XDKUnityCloudExamples/Common/Scripts/Tween/TweenAlphaCanvasGroup.cs

using UnityEngine;
using UnityEngine.UI;


/// <summary>
/// Tween the object's alpha.
/// </summary>

[RequireComponent(typeof(CanvasGroup))]
public class TweenAlphaCanvasGroup : Tweener
{
    [Range(0f, 1f)]
    public float from = 1f;
    [Range(0f, 1f)]
    public float to = 1f;

    public bool resetOnEnable = false;

    CanvasGroup m_CanvasGroup;
    public CanvasGroup canvasGroup {
        get {
            if (m_CanvasGroup == null)
                m_CanvasGroup = GetComponent<CanvasGroup>();
            return m_CanvasGroup;
        }
    }
    /// <summary>
    /// Tween's current value.
    /// </summary>

    public float value {
        get {
            return canvasGroup.alpha;
        }
        set {
            canvasGroup.alpha = value;
        }
    }


    void OnEnable()
    {
        if (resetOnEnable)
        {
            tweenFactor = 0;
            Sample(0, false);
        }
    }

    /// <summary>
    /// Tween the value.
    /// </summary>

    protected override void OnUpdate(float factor, bool isFinished)
    {
        value = Mathf.Lerp(from, to, factor);
    }

    /// <summary>
    /// Start the tweening operation.
    /// </summary>

    static public TweenAlphaCanvasGroup Begin(GameObject go, float duration, float alpha)
    {
        TweenAlphaCanvasGroup comp = Tweener.Begin<TweenAlphaCanvasGroup>(go, duration);
        comp.from = comp.value;
        comp.to = alpha;

        if (duration <= 0f)
        {
            comp.Sample(1f, true);
            comp.enabled = false;
        }
        return comp;
    }
    public override void Play(bool forward)
    {
        base.Play(forward);
    }

    public override void SetStartToCurrentValue()
    {
        from = value;
    }
    public override void SetEndToCurrentValue()
    {
        to = value;
    }
}