c# - Unity Button OnClick AddListener 问题 - 与 For Each Loop 中最后一项的回调相同

Question

所以我有一个脚本 (Unity C#)，它运行一个生成答案数组的 IEnumerator 函数，我想以列表格式显示它们。

所以我使用:

public Button QuestionButton;

void Start(){
    StartCoroutine(PresentQuestion());
}

IEnumerator PresentQuestion(){
    CurrentStage = Stage.QuestionStart;

    CurrentQuestion = "How many times do we have to do this to make it work?";
    Answers.Add ("1");
    Answers.Add ("2");
    Answers.Add ("3");
    Answers.Add ("4");

    float newY = 80.0f;
    foreach(string answer in Answers){
        newY-=65.0f;
        string locanswer = answer;
        Button btn = Instantiate(QuestionButton);
        btn.transform.position = new Vector3(225, newY, 0);
        btn.transform.SetParent(QuestionUI.transform, false);
        btn.gameObject.SetActive(true);
        btn.transform.FindChild("Text").GetComponent<Text>().text = locanswer;
        btn.onClick.AddListener(() => AnswerClicked(locanswer));
    }
    QuestionText.text = CurrentQuestion;
}

void AnswerClicked(string value){
    print (value);
}

QuestionButton 是我在检查器中链接的按钮游戏对象，它实例化很好，文本设置很好，但它是在我添加监听器时出现的。

当我去点击按钮时，我“每次”都得到循环中的最后一个字符串或 _answer。

我不确定为什么实例化的每个新 Button (btn) 对象都不会在 AnswerClicked 处获得自己的 Listener。谁能解释一下？

仅供引用:QuestionUI 是我的 Canvas 。

谢谢。

更新:

此代码有效，但我之前的问题仍然存在。我将尝试使用我的实际代码进行更新。

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

public class Testing : MonoBehaviour {

public string CurrentQuestion;
public ArrayList Answers = new ArrayList();

public Button QuestionButton;
public GameObject QuestionUI;
public Text QuestionText;

void Start(){
    StartCoroutine(PresentQuestion());
}

IEnumerator PresentQuestion(){
    CurrentQuestion = "How many times do we have to do this to make it work?";
    Answers.Add ("1");
    Answers.Add ("2");
    Answers.Add ("3");
    Answers.Add ("4");

    float newY = 80.0f;
    foreach(string answer in Answers){
        newY-=65.0f;
        string locanswer = answer;
        Button btn = Instantiate(QuestionButton);
        btn.transform.position = new Vector3(225, newY, 0);
        btn.transform.SetParent(QuestionUI.transform, false);
        btn.gameObject.SetActive(true);
        btn.transform.FindChild("Text").GetComponent<Text>().text = locanswer;
        btn.onClick.AddListener(() => AnswerClicked(locanswer));
    }
    QuestionText.text = CurrentQuestion;

    return null;
}

void AnswerClicked(string value){
    print (value);
}
}

Answer 1

我遇到了同样的问题，我发现在单独的方法中设置 onClick 监听器对我有用。

在这种情况下我会这样做:

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

public class Testing : MonoBehaviour {

    public string CurrentQuestion;
    public ArrayList Answers = new ArrayList();

    public Button QuestionButton;
    public GameObject QuestionUI;
    public Text QuestionText;

    void Start(){
        StartCoroutine(PresentQuestion());
    }

    IEnumerator PresentQuestion(){
        CurrentQuestion = "How many times do we have to do this to make it work?";
        Answers.Add ("1");
        Answers.Add ("2");
        Answers.Add ("3");
        Answers.Add ("4");

        float newY = 80.0f;
        foreach(string answer in Answers){
            newY-=65.0f;
            Button btn = Instantiate(QuestionButton);
            btn.transform.position = new Vector3(225, newY, 0);
            btn.transform.SetParent(QuestionUI.transform, false);
            btn.gameObject.SetActive(true);
            btn.transform.FindChild("Text").GetComponent<Text>().text = locanswer;
            SetButtonOnClick(btn, answer);
        }
        QuestionText.text = CurrentQuestion;

        return null;
    }

    void SetButtonOnClickAnswer(Button button, string value){
        button.onClick.AddListener(() => AnswerClicked(value));
    }

    void AnswerClicked(string value){
        print (value);
    }
}

(免责声明:我没有对此进行测试，但我在我的项目中运行了一个非常相似的代码，这解决了问题。)