java - 从多种方法中选择随机方法

Question

我试图从类内创建的方法中选择一个随机方法。有没有办法创建 ArrayList 并向其传递方法？我已经尝试这样做，但是当我尝试将该方法添加到数组时出现错误。

public class Monkey{

    private int energy;

    String[] food = {"Meat", "Fish", "Bugs", "Grain"};
    ArrayList<Activity> monkeyActivity = new ArrayList<>();

    public Monkey(int energy) {
        this.energy = energy;
    }

    public int getEnergy() {
        System.out.println("Monkey energy level: " + energy);
        return energy;
    }

    public void sound() {
        System.out.println("Monkey: Oooo Oooo~!");
        energy -= 3;
        monkeyActivity.add(sound()); //I get an error message here when trying 
                                 //to add the method to the array
    }

    public void play(){
        if (energy >= 8){
            System.out.println("Monkey begins to play.");
            energy -= 8;
        }else {
            System.out.println("Monkey does not have enough energy to play");
        }
        System.out.println("Energy remaining: " + energy);
    }

    public void eat(){
        Random random = new Random();
        int index = random.nextInt(food.length);
        System.out.println("Monkey beings to eat " + food[index]);
        energy += 5;
        System.out.println("Energy remaining: " + energy);
    }

    public void sleep(){
        System.out.println("Monkey is sleeping: Zzz...");
        energy += 10;
        System.out.println("Energy remaining: " + energy);
    }
}

这是我为通用 Activity 制作的单独的类..

public class Activity {

    private String sleep;
    private String eat;
    private String sound;
    private String play;

    public Activity(String sleep, String eat, String sound, String play) {
        this.sleep = sleep;
        this.eat = eat;
        this.sound = sound;
        this.play = play;
    }

    public String getSleep() {
        return sleep;
    }

    public String getEat() {
        return eat;
    }

    public String getSound() {
        return sound;
    }

    public String getPlay() {
        return play;
    }

    public void setSleep(String sleep) {
        this.sleep = sleep;
    }

    public void setEat(String eat) {
        this.eat = eat;
    }

    public void setSound(String sound) {
        this.sound = sound;
    }

    public void setPlay(String play) {
        this.play = play;
    }
}

Answer 1

你混淆了概念。

技术问题:

返回值冲突

public void sound() {
    // ...
    monkeyActivity.add(sound());

您的方法 sound() 的返回值是 void(这意味着无返回值)，但您尝试添加其 (不存在)将值作为元素返回到列表。这就是你的编译器所提示的。

意外递归

public void sound() {
    System.out.println("Monkey: Oooo Oooo~!");
    energy -= 3;
    monkeyActivity.add(sound());

在最后一行中，您执行了一个递归调用，这意味着您调用了与此代码所在的完全相同的方法。如果这种情况意外发生，则几乎会导致 StackOverflowError .

在没有适当分析的情况下编写类

您有一个类Activity。 但如果您仔细观察，这不是一个单个 Activity (正如类名称所暗示的那样)，而是所有可能的 Activity 。

因此，您的集合 monkeyActivity 无法将单个 Activity 作为元素保存。

大胆猜测，我认为你想要的更像是这样的:

interface Activity{
  void do();
}

public class Monkey{
    private int energy;
    String[] food = {"Meat", "Fish", "Bugs", "Grain"};
    List<Activity> monkeyActivity = new ArrayList<>();
    // ...        
    public void sound() {
        monkeyActivity.add(new Activity(){
              public void do(){                
                System.out.println("Monkey: Oooo Oooo~!");
                energy -= 3;
              }
           }); 
    }