Question

剧院的舞台上安装了聚光灯。每个聚光灯都可以打开，关闭或变暗。写一个名为Spotlight的类来表示聚光灯。该类应具有一个字段变量status，以存储聚光灯的状态（开，关或变暗）。除了构造函数之外，您的类还应包含以下方法：

  如果聚光灯关闭，
isOff()将返回true，否则返回false
  如果聚光灯亮起，
isOn()将返回true，否则返回false
  如果聚光灯变暗，则
isDimmed()返回true，否则返回false

on()让人们关注

off()关闭聚光灯

dim()使聚光灯变暗

toString将有关聚光灯的信息作为字符串返回。

所以这是我的班级，到目前为止我所拥有的：

class Spotlight
{
    private String status; //the status of the spotlight



    //constructor
    public Spotlight(String s)
    {
        status = s;
    }

    //get the spotlights status
    public String getStatus()
    {
        return status;
    }

    //set the spotlights status
    public void setStatus(String newS)
    {
        status = newS;
    }

    //method to show that the spotlight is off
    public boolean isOff()
    {
        if (status.equalsIgnoreCase("Off"))

        {
            return true;
        }
        else
        {
            return false;
        }


    }

    //method to show that the spotlight is on
    public boolean isOn()
    {
             if (status.equalsIgnoreCase("On"))
        {
            return true;
        }
        else
        {
            return false;
        }

    }

    //method to show that the spotlight is dimmed
    public boolean isDimmed()
    {
              return false;

    }

    //method to show that the spotlight is off
    public boolean on()
    {
              if (status.equalsIgnoreCase("On"))
        {
            return true;
        }
        else
        {
            return false;
        }

    }

    //method to show that the spotlight is off
    public boolean off()
    {
              if (status.equalsIgnoreCase("Off"))
        {
            return true;
        }
        else
        {
            return false;
        }

    }

    //method to show that the spotlight is off
    public boolean dim()
    {
              return false;

    }


    //return all the information about the employee as a String
    public String toString()
    {
        return "Status: " + this.getStatus(); 
    }

}


       Spotlight a = new Spotlight("Off");
       Spotlight b = new Spotlight("Off");
       Spotlight c = new Spotlight("Off");
       Spotlight d = new Spotlight("Off");
       Spotlight e = new Spotlight("Off");


        //print out the information about them 
           System.out.println();
           System.out.println(a.toString());
           System.out.println();
           System.out.println(b.toString());
           System.out.println();
           System.out.println(c.toString());
           System.out.println(); 
           System.out.println(d.toString());
           System.out.println();
           System.out.println(e.toString());
           System.out.println(); 

           System.out.println("Select a light to turn on a-e");
           Scanner sc = new Scanner(System.in);
           String input = sc.nextLine();
           Spotlight f = new Spotlight(input);

到目前为止，我可以更改聚光灯的状态并让它显示我的结果，但如果我使用的是二十个聚光灯对象，我该如何选择要打开的灯？

Answer 1

简单方法：

List<SpotLight> spotlights = new ArrayList<>();
for(int i = 0; i < 20; i++)
    spotlights.add(new SpotLight("Off"));

int choice = 0;
do {
    System.out.println("Select a light to turn on 1-20");
    choice = sc.nextInt();
} while(choice < 1 || choice > 20);

spotlights.get(choice - 1).on();

System.out.println(spotlights);

另请参阅List和ArrayList上的文档。

作为旁注，您应该让您的聚光灯课程使用enum代替这些字符串：

public class SpotLight {     
    public enum State {
        On,
        Off,
        Dimmed
    }

    private State state;

    public SpotLight(State state) {
        this.state = state;
    }

    ...
}

然后，例如，创建一个聚光灯：

SpotLight spotlight = new SpotLight(SpotLight.State.Off);

如何在Java中选择一个对象来更改其字段？

1 个答案: