UIGU源码分析8：Slider

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已于 2022-03-08 00:00:04 修改 · 3.2k 阅读

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#unity #游戏引擎

于 2022-03-07 23:59:47 首次发布

本文详细介绍了Unity引擎中UI Slider组件的工作原理和功能。Slider继承了Selectable, IDragHandler, IInitializePotentialDragHandler, ICanvasElement等接口，用于创建可拖动的进度条。它包含填充矩形和手柄矩形，根据方向和值来调整显示。Set方法限制并设置值，OnPointerDown处理鼠标按下事件，OnMove处理方向键移动事件，OnDrag更新拖动状态。 SliderEvent事件在值改变时触发，并更新视觉效果。

源码8：Slider

  public class Slider : Selectable, IDragHandler, IInitializePotentialDragHandler, ICanvasElement
    {
    	...
    	
    	  [Serializable]
        /// <summary>
        /// Event type used by the UI.Slider.
        /// </summary>
        public class SliderEvent : UnityEvent<float> {}

        [SerializeField]
        private RectTransform m_FillRect;
        
          [SerializeField]
        private RectTransform m_HandleRect;
        
            [SerializeField]
        private Direction m_Direction = Direction.LeftToRight;
        
          [SerializeField]
        private float m_MinValue = 0;
        
        [SerializeField]
        private float m_MaxValue = 1;
        
            [SerializeField]
        private bool m_WholeNumbers = false;
        
         [SerializeField]
        protected float m_Value;
        
          public SliderEvent onValueChanged { get { return m_OnValueChanged; } set { m_OnValueChanged = value; } }
    	...
    
    }

Slider 继承了Selectable, IDragHandler, IInitializePotentialDragHandler, ICanvasElement 功能基本和Scrollbar类似

   protected virtual void Set(float input, bool sendCallback = true)
    {
        // Clamp the input
        float newValue = ClampValue(input);

        // If the stepped value doesn't match the last one, it's time to update
        if (m_Val