在列表中设置活动游戏对象

Question

我正在为 Android 2d 应用程序制作菜单，我在多个菜单中有一堆 UI 面板，当我按下下一个右键或上一个左按钮时，脚本应该将下一个面板设置为活动状态并停用上一个面板，我尝试使用带有游戏对象的公共类执行此操作，但这不起作用，并认为列表应该有效。

在 Unity 编辑器中，我将大小设置为 4，并将 4 个面板拖到脚本中我收到此错误：

ArgumentOutOfRangeException：Argument超出范围。 参数名称：索引

以下是脚本的相关部分：

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
public class MenuControl : MonoBehaviour
{
    //Buttons
    public GameObject ShipUpgradeRight;
    public GameObject ShipUpgradeLeft;
    //Ships
    private int shipUpgradeSelected = 0;
    List<GameObject> ShipList = new List<GameObject>();
    public void Keyword (string keyword)
    {
        if (keyword == "ShipUpgradeLeft") {
            shipUpgradeSelected--;
            ShipList[shipUpgradeSelected].SetActive (true);
            ShipList[shipUpgradeSelected+1].SetActive (false);
        }
        if (keyword == "ShipUpgradeRight") {
            shipUpgradeSelected--;
            CheckShip ();
            ShipList[shipUpgradeSelected].SetActive (true);
            ShipList[shipUpgradeSelected-1].SetActive (false);
        }   
    }
}

Answer 1

根据您的评论和实际问题，我认为一个可能的问题。

shipUpgradeSelected的价值永远不会增加。此外，shipUpgradeSelected的初始值为零。

public void Keyword (string keyword)
{
    if (keyword == "ShipUpgradeLeft") {
        shipUpgradeSelected--;
        ShipList[shipUpgradeSelected].SetActive (true);
        ShipList[shipUpgradeSelected+1].SetActive (false);
    }
    if (keyword == "ShipUpgradeRight") {
        shipUpgradeSelected--;
        CheckShip ();
        ShipList[shipUpgradeSelected].SetActive (true);
        ShipList[shipUpgradeSelected-1].SetActive (false);
    }   
}

当keyword等于ShipUpgradeRight或ShipUpgradeLeft时，shipUpgradeSelected的值会减小（因此小于零）。然后，您尝试访问索引处小于零的列表项。

但这是第一个问题。

此外，您不会夹紧（或不循环）shipUpgradeSelected的值。所以例如你有

if (keyword == "ShipUpgradeRight") {
    shipUpgradeSelected++;
    CheckShip ();
    ShipList[shipUpgradeSelected].SetActive (true);
    ShipList[shipUpgradeSelected-1].SetActive (false);
}

例如，如果调用Keyword("ShipUpgradeRight");五次，则 shipUpgradeSelected 的值为 5。它再次超出范围。所以你需要决定如何夹紧这个变量的值。

Answer 2

这段代码非常有效：

public void Keyword(string keyword) {
         if (keyword == "ShipUpgradeLeft") {
             shipUpgradeSelected--;
             if (shipUpgradeSelected < 0) {
                 shipUpgradeSelected = 0;
                 return;
             }
             ShipList[shipUpgradeSelected].SetActive(true);
             if (shipUpgradeSelected + 1 < ShipList.Count) ShipList[shipUpgradeSelected + 1].SetActive(false);
             else ShipList[0].SetActive(false);
         }
         if (keyword == "ShipUpgradeRight") {
             shipUpgradeSelected++;
             if (shipUpgradeSelected >= ShipList.Count) {
                 shipUpgradeSelected = ShipList.Count - 1;
                 return;
             }
             ShipList[shipUpgradeSelected].SetActive(true);
             if (shipUpgradeSelected > 0) ShipList[shipUpgradeSelected - 1].SetActive(false);
             else ShipList[ShipList.Count-1].SetActive(false);
         }
     }

但是如果我重新开始，我会这样做：

private void Start()
 {
     ShipUpgradeLeft.GetComponent<Button>().onClick.AddListener(() => { Previous(); });
     ShipUpgradeRight.GetComponent<Button>().onClick.AddListener(() => { Next(); });
 }
 public void Next()
 {
     ShipList[shipUpgradeSelected].SetActive(false);
     shipUpgradeSelected = Mathf.Clamp(shipUpgradeSelected++, 0, ShipList.Count - 1);
     ShipList[shipUpgradeSelected].SetActive(true);
 }
 public void Previous()
 {
     ShipList[shipUpgradeSelected].SetActive(false);
     shipUpgradeSelected = Mathf.Clamp(shipUpgradeSelected--, 0, ShipList.Count - 1);
     ShipList[shipUpgradeSelected].SetActive(true);
 }

感谢瓦尔特和d12frosted帮助我解决问题