如何编程自定义按钮以浏览使用Scroll Rect与Mask结合创建的滚动视图

Question

我有一个商店GUI，其内容在使用Scroll Rect和Mask组合创建的srollview中，可以向下和向上滚动。

现在，滚动视图通过在滚动视图区域中的任意位置单击并拖动来滚动，或者通过与垂直滚动条交互来滚动。

如何使用自定义向上和向下按钮（在下面的附加图像上用红色圈出来）来进行滚动？

Answer 1

将以下脚本复制到项目中，并将ScrollRectSnap脚本应用于滚动视图。知道你是否这样做是为了让你的滚动视图按下按钮点击只需使用向上和向下按钮执行以下链接 UpArrowPressed 和 DownArrowPressed ，并且不要忘记检查<如果您有垂直滚动视图，请选择 ScrollRectSnap 的检查器中的strong> Snap In V 参数，也不要被DownArrowPressed函数中的snapper.DraggedOnRight（）调用弄糊涂，就好像您选中了 Snap In V 参数然后它会像snapper.DraggedOnLeft（）那样按下你自己的行为，你可以根据你的要求设置其他参数，你必须根据你的要求来获取它。

public void UpArrowPressed()
{
    ScrollRectSnap snapper = GetComponentInChildren<ScrollRectSnap>();
    snapper.DraggedOnLeft();
}

public void DownArrowPressed()
{
    ScrollRectSnap snapper = GetComponentInChildren<ScrollRectSnap>();
    snapper.DraggedOnRight();

}

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using System;

public class ScrollRectSnap : MonoBehaviour 
{
	
	float[] points;
	[Tooltip("how many screens or pages are there within the content (steps)")]
	public int screens = 1;
	[Tooltip("How quickly the GUI snaps to each panel")]
	public float snapSpeed;
	public float inertiaCutoffMagnitude;
	float stepSize;
	
	ScrollRect scroll;
	bool LerpH;
	float targetH;
	[Tooltip("Snap horizontally")]
	public bool snapInH = true;
	
	bool LerpV;
	float targetV;
	[Tooltip("Snap vertically")]
	public bool snapInV = true;

	public string controllTag;
	bool dragInit = true;
	int dragStartNearest;
	float horizontalNormalizedPosition;
	float verticalNormalizedPosition;

	public static event Action<int,int> OnEndReached;
	public static event Action<int,int,string> OnEndReachedWithTag;

	// Use this for initialization
	void Start()
	{
		Init();
//		SnapToSelectedIndex(0);
	}

	void Init()
	{
		scroll = gameObject.GetComponent<ScrollRect>();
		scroll.inertia = true;
		
		if (screens > 0)
		{
			points = new float[screens];
			stepSize = (float)Math.Round(1 / (float)(screens - 1),2);
			
			for (int i = 0; i < screens; i++)
			{
				points[i] = i * stepSize;
			}
		}
		else
		{
			points[0] = 0;
		}
	}

	void OnEnable()
	{

	}

	void Update()
	{
		horizontalNormalizedPosition = scroll.horizontalNormalizedPosition;
		verticalNormalizedPosition = scroll.verticalNormalizedPosition;

		if (LerpH)
		{
			scroll.horizontalNormalizedPosition = Mathf.Lerp(scroll.horizontalNormalizedPosition, targetH, snapSpeed * Time.deltaTime);
			if (Mathf.Approximately((float)Math.Round(scroll.horizontalNormalizedPosition,2), targetH)) 
			{
				LerpH = false;
				int target = FindNearest(scroll.horizontalNormalizedPosition, points);
//				Debug.LogError("Target : " + target);
				if (target == points.Length-1) 
				{
					if (OnEndReached != null)  
					{
						OnEndReached(1,target);	
					}
					if(OnEndReachedWithTag != null)
					{
						OnEndReachedWithTag(1,target,controllTag);
					}
				}
				else if (target == 0)  
				{
					if (OnEndReached != null)  
					{
						OnEndReached(-1,target);	
					}
					if(OnEndReachedWithTag != null)
					{
						OnEndReachedWithTag(-1,target,controllTag);
					}
				}
				else
				{
					if (OnEndReached != null)  
					{
						OnEndReached(0,target);	
					}
					if(OnEndReachedWithTag != null)
					{
						OnEndReachedWithTag(0,target,controllTag);
					}
				}
			
			}
		}
		if (LerpV)
		{
			scroll.verticalNormalizedPosition = Mathf.Lerp(scroll.verticalNormalizedPosition, targetV, snapSpeed * Time.deltaTime);
			if (Mathf.Approximately(scroll.verticalNormalizedPosition, targetV)) 
			{
				LerpV = false;
			}
		}
	}
	
	public void DragEnd()
	{
		int target = FindNearest(scroll.horizontalNormalizedPosition, points);
		
		if (target == dragStartNearest && scroll.velocity.sqrMagnitude > inertiaCutoffMagnitude * inertiaCutoffMagnitude)
		{
			if (scroll.velocity.x < 0)
			{
				target = dragStartNearest + 1;
			}
			else if (scroll.velocity.x > 1)
			{
				target = dragStartNearest - 1;
			}
			target = Mathf.Clamp(target, 0, points.Length - 1);
		}
		
		if (scroll.horizontal && snapInH )
		{
			targetH = points[target];
			LerpH = true;
		}
		if (scroll.vertical && snapInV && scroll.verticalNormalizedPosition > 0f && scroll.verticalNormalizedPosition < 1f)
		{
			targetH = points[target];
			LerpH = true;
		}
		
		dragInit = true;
	}
	
	public void OnDrag()
	{
		if (dragInit)
		{
			if (scroll == null)  
			{
				scroll = gameObject.GetComponent<ScrollRect>();	
			}
			dragStartNearest = FindNearest(scroll.horizontalNormalizedPosition, points);
			dragInit = false;
		}
		
		LerpH = false;
		LerpV = false;
	}
	
	int FindNearest(float f, float[] array)
	{
		float distance = Mathf.Infinity;
		int output = 0;
		for (int index = 0; index < array.Length; index++)
		{
			if (Mathf.Abs(array[index] - f) < distance)
			{
				distance = Mathf.Abs(array[index] - f);
				output = index;
			}
		}
		return output;
	}

	public void DraggedOnLeft()
	{
		OnDrag();

		if (scroll.horizontal && snapInH && scroll.horizontalNormalizedPosition > -0.001f && scroll.horizontalNormalizedPosition < 1.001f)
		{
//			Debug.Log("Before Press, LerpH : " + LerpH);
			if (dragStartNearest < points.Length-1)  
			{
				targetH = points[dragStartNearest+1];
				LerpH = true;
			}
			else
			{
				targetH = points[dragStartNearest];
				LerpH = true;
			}
//			Debug.Log("After Press, LerpH : " + LerpH);
		}
		if (scroll.vertical && snapInV && scroll.verticalNormalizedPosition > 0f && scroll.verticalNormalizedPosition < 1f)
		{

			if (dragStartNearest < points.Length-1)  
			{
				targetV = points[dragStartNearest+1];
				LerpV = true;
			}
			else
			{
				targetV = points[dragStartNearest];
				LerpV = true;
			}
		}
		
		dragInit = true;
	}
	public void DraggedOnRight()
	{
		OnDrag();
		
		if (scroll.horizontal && snapInH && scroll.horizontalNormalizedPosition > -0.001f && scroll.horizontalNormalizedPosition < 1.001f)
		{
			if (dragStartNearest>0)  
			{
				targetH = points[dragStartNearest-1];
				LerpH = true;
			}
			else
			{
				targetH = points[dragStartNearest];
				LerpH = true;
			}
		}
		if (scroll.vertical && snapInV && scroll.verticalNormalizedPosition > 0f && scroll.verticalNormalizedPosition < 1f)
		{
			if (dragStartNearest > 0) 
			{
				targetV = points[dragStartNearest-1];
				LerpV = true;				
			}
			else
			{
				targetV = points[dragStartNearest];
				LerpV = true;				
			}
		}
		
		dragInit = true;
	}

	public void SnapToSelectedIndex(int index)
	{
		if (points == null)  
		{
			Init();			
		}
		dragInit = false;
		LerpH = false;
		LerpV = false;
		targetH = points[index];
		LerpH = true;
		dragInit = true;
	}

}