Question by CameronStewart21 · Apr 19, 2020 at 07:13 AM · c#scrollview recttransform menu screen arrow-keys

How could I navigate horizontally through a scroll view using left and right arrow keys?

I have a working horizontal scroll view to be used as a scrollable "skills menu" for a basketball game I am creating. My issue is, that this game is going to be for PC, and therefore I feel that scrolling through this using only the mouse is not effective and I would like to use the arrow keys to select through each option in the scroll view. Perhaps there is a better way of implementing this system as opposed to a scroll view but so far I have it working well enough, it scales dynamically, and snaps to the nearest option.

Here is my entire script for the scrollview.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 using UnityEngine.EventSystems;
 using TMPro;
 
 public class SkillScrolling : MonoBehaviour
 {
     [Header("Controllers")]
     public int skillCount;
 
     [Range(0, 500)]
     public int offset;
 
     [Range(0f,20f)]
     public float snapSpeed;
 
     [Range(0f, 10f)]
     public float scaleOffset;
 
     [Range(0f, 20f)]
     public float scaleSpeed;
 
     [Header("Other Objects")]
     public TextMeshProUGUI skillText;
     public GameObject skillPrefab;
 
     public string[] skillTypes;
     private GameObject[] instSkills;
     private Vector2[] skillPos;
     private Vector2[] skillScale;
 
     private RectTransform contentRect;
     private Vector2 contentPos;
     public int selectedSkillID;
 
     public bool isScrolling = false;
     // Start is called before the first frame update
     void Start()
     {
         skillText = skillPrefab.GetComponentInChildren<TextMeshProUGUI>();
         contentRect = GetComponent<RectTransform>();
         instSkills = new GameObject[skillCount];
         skillPos = new Vector2[skillCount];
         skillScale = new Vector2[skillCount];
 
         //instantiates the amount of skills specified and alligns them/sets them apart using an offset.
         for (int i = 0; i < skillCount; i++) 
         {
             skillText.text = skillTypes[i];
             instSkills[i] = Instantiate(skillPrefab, transform, false);
             if (i == 0) continue;
             instSkills[i].transform.localPosition = new Vector2(instSkills[i-1].transform.localPosition.x + skillPrefab.GetComponent<RectTransform>().sizeDelta.x + offset, instSkills[i].transform.localPosition.y);
             skillPos[i] = -instSkills[i].transform.localPosition;
         }
     }
 
     // Update is called once per frame
     void Update()
     {
         float nearestPos = float.MaxValue;
         for (int i = 0; i < skillCount; i++)
         {
             //distance between one skill selection and the next one.
             float distance = Mathf.Abs(contentRect.anchoredPosition.x - skillPos[i].x);
             //check if the distance is less than the nearest position.
             if (distance < nearestPos)
             {
                 nearestPos = distance; //distance becomes relative to nearest position.
                 selectedSkillID = i; //identifies which selection is nearest.
             }
             float scale = Mathf.Clamp(1 / (distance / offset) * scaleOffset, 0.5f, 1f); //restricts the scale size of the unselected options.
 
             //smoothly steps through the scale of the items to produce a growing and shrinking effect.
             skillScale[i].x = Mathf.SmoothStep(instSkills[i].transform.localScale.x, scale, scaleSpeed + .3f * Time.unscaledDeltaTime);
             skillScale[i].y = Mathf.SmoothStep(instSkills[i].transform.localScale.y, scale, scaleSpeed + .3f * Time.unscaledDeltaTime);
             //sets the scale of the current item.
             instSkills[i].transform.localScale = skillScale[i];
         }
         if (isScrolling) return;
         //smoothly steps through the snapping into the position of the nearest item.
         contentPos.x = Mathf.SmoothStep(contentRect.anchoredPosition.x, skillPos[selectedSkillID].x, snapSpeed * Time.unscaledDeltaTime);
         contentRect.anchoredPosition = contentPos;
 
         if (Input.GetKeyDown(KeyCode.LeftArrow) && selectedSkillID > 0)
         {
             selectedSkillID -= 1;
 
         }
 
         if (Input.GetKeyDown(KeyCode.RightArrow) && selectedSkillID < 6)
         {
             selectedSkillID += 1;
         }
     }
 
 //checks if is scrolling or not.
     public void Scrolling(bool scroll)
     {
         isScrolling = scroll;
     }
 }

Thanks!

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