如何构建具有多变量的随机对象？

Question

这是我的主要节目。我在这里试图实现的是，对于每一个"HeadPhones“设置有一个随机生成的颜色和制造商。目前，当程序运行时，除了我预置的内容外，所有变量都得到相同的结果。

package testheadphones;

import java.util.Random;

public class TestHeadPhones {



public static void main(String[] args) {

    String[] manufacturers = {"Skullcandy", "Klipsch", "Grado", "Shure",
    "Bose", "Beats", "Sony"};
    String[] colors = {"blue", "black", "green", "red", "purple", "pink",
    "white", "orange", "yellow"};



    Random random = new Random();
    int randColor = random.nextInt(2);
    String color = colors[randColor];
    int randMan = random.nextInt(2);
    String manufacturer = manufacturers[randMan];


    //Build three headphone sets.
    //Each set is encased in "{}" just for organization
    HeadPhones set1 = new HeadPhones();{
    set1.setIsPluggedIn(true);
    set1.getManufacturer();
    set1.setManufacturer(manufacturer);
    set1.getVolume();
    set1.setVolume(2);
    set1.getColor();
    set1.setColor(color);
    }

    HeadPhones set2 = new HeadPhones();{
    set2.setIsPluggedIn(true);
    set2.getManufacturer();
    set2.setManufacturer(manufacturer);
    set2.getVolume();
    set2.setVolume(1);
    set2.getColor();
    set2.setColor(color);
    }

    HeadPhones set3 = new HeadPhones();{
    set3.setIsPluggedIn(true);
    set3.getManufacturer();
    set3.setManufacturer(manufacturer);
    set3.getVolume();
    set3.setVolume(3);
    set3.getColor();
    set3.setColor(color);
    }

    System.out.println(set1.toString());
    System.out.println();
    System.out.println(set2.toString());
    System.out.println();
    System.out.println(set3.toString());

}

}

这是我的班级档案。

    package testheadphones;

import java.util.Random;

public class HeadPhones {

//Constant Declarations
public static final int LOW = 1;
public static final int MEDIUM = 2;
public static final int HIGH = 3;

//Private Declarations
private int volume = MEDIUM;
private boolean pluggedIn = false;
private String manufacturer = null;
private String color = null;

Random random = new Random();

//Default Constructor
public void HeadPhones (int volume, String manufacturer, String Color){
    pluggedIn = false;
    manufacturer = "Sony";
    color = "red";
    volume = MEDIUM;
}

//Getter and Setter
public int getVolume(){
    return volume;
}
public void setVolume(int volume){
    this.volume = volume;
}
public String getManufacturer(){
    return manufacturer;
}
public void setManufacturer(String manufacturer){
    this.manufacturer = manufacturer;
}
public boolean getIsPluggedIn(){
    return pluggedIn;
}
public void setIsPluggedIn(boolean pluggedIn){
    this.pluggedIn = pluggedIn;
}
public String getColor(){
    return color;
}
public void setColor(String color){
    this.color = color;
}

public String toString(){
    String plugIn = this.pluggedIn == true ? "plugged in. " : "not plugged"
            + " in. ";

    String earBuds = "Your headphones are " + plugIn + "They are: " + 
            this.color + " " + this.manufacturer + " and are turned up to "
   + this.volume;

    return earBuds;
}

}

Answer 1

因为问题还不清楚，我会试着理解你想要什么。

我想要在整个数组中找到一个随机元素，而不仅仅是两个第一个元素：random.nextInt(colors.length);和random.nextInt(manufacturers.length);，而不是random.nextInt(colors.length);。

您创建一个整数，并使用它的3个耳机。你可能想为每个耳机选择一个新的颜色和一个新的制造商。然后将setX.setManufacturer(manufacturer);和setX.setColor(color);替换为：

setX.setManufacturer(manufacturers[random.nextInt(manufacturers.length)]);
setX.setColor(colors[random.nextInt(colors.length)]);

Answer 2

可能有一个错误，我可以看到您是generating random number between 0 (inclusive) and the specified value i.e 2(exclusive)，即只有两个值是generated 1 and 0。您需要在更多范围之间生成它。

解决这个问题

Random random = new Random();
    int randColor = random.nextInt(manufacturers.length);
    String color = colors[randColor];
    int randMan = random.nextInt(colors.length);

Answer 3

当你说

    int randMan = random.nextInt(2)

你说的是随机类，它在0到1之间生成一个随机的int (2除外)。可能您想要做的是在0和

    manufacturers.length

颜色也是如此。所以你需要的是：

    int randColor = random.nextInt(colors.length);
    int randMan = random.nextInt(manufacturers.length);