Question

我有点困惑的是，当点击任何hero.attacks时，为什么此函数始终将li.attack设置为hero.atatcks - 数组的第一个元素？我正在尝试将其设置为相应的var hero = { attacks: [{ name: "atck1" }, { name: "atck2" }, { name: "atck3" }, { name: "atck4" }] }; var attacks = document.getElementsByClassName("attack"); for (var i = 0; i < attacks.length; i++) { var atck = hero.attacks[i]; attacks[i].addEventListener("click", function (event) { document.getElementById("attack").innerText = atck.name; }) } - 元素的名称。我已尝试使用for循环和foreach以及循环之外的索引集，每次迭代都会增加，但似乎没有任何效果？

http://jsfiddle.net/47r768p8/2/

使用Javascript：

<ul>
    <li class="attack">Atck1</li>
    <li class="attack">Atck2</li>
    <li class="attack">Atck3</li>
    <li class="attack">Atck4</li>
</ul>
<h1 id="attack"></h1>

HTML：

using UnityEngine;
using System.Collections;

public class FormationController : MonoBehaviour
{   //Spawning Variables
    public GameObject EnemyPrefab;
    public float W = 10, H = 5;
    //Movement Variables
    public float Speed = 5;
    private int Direction;
    private float BoundaryRightEdge, BoundaryLeftEdge;
    public float Padding = 0.25f;


void Start() //Setting Boundary
{
    Camera camera = GameObject.Find("Player").GetComponentInChildren<Camera>();
    float distance = camera.transform.position.z - camera.transform.position.z;
    BoundaryLeftEdge = camera.ViewportToWorldPoint(new Vector3(0, 0, distance)).x + Padding;
    BoundaryRightEdge = camera.ViewportToWorldPoint(new Vector3(1, 1, distance)).x - Padding;
}

void OnDrawGizmos()
{
    float xmin, xmax, ymin, ymax;
    xmin = transform.position.x - 0.5f * W;
    xmax = transform.position.x + 0.5f * W;
    ymin = transform.position.y - 0.5f * H;
    ymax = transform.position.y + 0.5f * H;
    Gizmos.DrawLine(new Vector3(xmin, ymin, 0), new Vector3(xmin, ymax));
    Gizmos.DrawLine(new Vector3(xmin, ymax, 0), new Vector3(xmax, ymax));
    Gizmos.DrawLine(new Vector3(xmax, ymax, 0), new Vector3(xmax, ymin));
    Gizmos.DrawLine(new Vector3(xmax, ymin, 0), new Vector3(xmin, ymin));

}

void Update()
{
    float formationRightEdge = transform.position.x + 0.5f * W;
    float formationLeftEdge = transform.position.x - 0.5f * W;
    if (formationRightEdge > BoundaryRightEdge)
    {
        Direction = -1;
    }
    if (formationLeftEdge < BoundaryLeftEdge)
    {
        Direction = 1;
    }
    transform.position += new Vector3(Direction * Speed * Time.deltaTime, 0, 0);

    //Spawn Enemies on Keypress
    if (Input.GetKeyDown(KeyCode.S))
    {
        foreach (Transform child in transform)
        {
            GameObject enemy = Instantiate(EnemyPrefab, child.transform.position, Quaternion.identity) as GameObject;
            enemy.transform.parent = child;
        }
    }
}

Answer 1

您的数组// Production steps of ECMA-262, Edition 5, 15.4.4.19 // Reference: http://es5.github.io/#x15.4.4.19 if (!Array.prototype.map) { Array.prototype.map = function(callback, thisArg) { var T, A, k; if (this == null) { throw new TypeError(' this is null or not defined'); } // 1. Let O be the result of calling ToObject passing the |this| // value as the argument. var O = Object(this); // 2. Let lenValue be the result of calling the Get internal // method of O with the argument "length". // 3. Let len be ToUint32(lenValue). var len = O.length >>> 0; // 4. If IsCallable(callback) is false, throw a TypeError exception. // See: http://es5.github.com/#x9.11 if (typeof callback !== 'function') { throw new TypeError(callback + ' is not a function'); } // 5. If thisArg was supplied, let T be thisArg; else let T be undefined. if (arguments.length > 1) { T = thisArg; } // 6. Let A be a new array created as if by the expression new Array(len) // where Array is the standard built-in constructor with that name and // len is the value of len. A = new Array(len); // 7. Let k be 0 k = 0; // 8. Repeat, while k < len while (k < len) { var kValue, mappedValue; // a. Let Pk be ToString(k). // This is implicit for LHS operands of the in operator // b. Let kPresent be the result of calling the HasProperty internal // method of O with argument Pk. // This step can be combined with c // c. If kPresent is true, then if (k in O) { // i. Let kValue be the result of calling the Get internal // method of O with argument Pk. kValue = O[k]; // ii. Let mappedValue be the result of calling the Call internal // method of callback with T as the this value and argument // list containing kValue, k, and O. mappedValue = callback.call(T, kValue, k, O); // iii. Call the DefineOwnProperty internal method of A with arguments // Pk, Property Descriptor // { Value: mappedValue, // Writable: true, // Enumerable: true, // Configurable: true }, // and false. // In browsers that support Object.defineProperty, use the following: // Object.defineProperty(A, k, { // value: mappedValue, // writable: true, // enumerable: true, // configurable: true // }); // For best browser support, use the following: A[k] = mappedValue; } // d. Increase k by 1. k++; } // 9. return A return A; }; }由相同的项组成，重复多次，这就是为什么它似乎每次都设置相同的项目。请尝试以下方法：

hero.attacks

为什么这个函数只返回数组的最后一个元素？

1 个答案: