如何在 java 中的不同 class 中重新生成随机数？

Question

我对 Java 还是很陌生，所以如果我的问题看起来很明显，请原谅我......我正在制作一个随机侮辱生成器，它可以使用的所有单词“词汇表”都在名为 generate() 的 class 中。 我希望能够在一个名为 randomize() 的方法中从 generate() 中更改一个随机生成的数字，该方法是在另一个名为侮辱Generator() 的 class 中。 这是我的insultGenerator() class的代码：

import java.awt.Dimension;
import java.awt.event.*;
import java.util.Random;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingConstants;

public class insultGenerator {

    public static void main(String args[]){

        generate g = new generate();

        g.frame.setLayout(null);
        g.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JButton button = new JButton("Generate New Insult");
        button.setBounds(75, 100, 150, 40);
        button.addActionListener(new Action());
        g.frame.add(button);

        g.frame.setPreferredSize(new Dimension(300, 200));
        g.frame.setLocationRelativeTo(null);
        g.frame.pack();
        g.frame.setVisible(true);

        if(g.beginning == 0) {
            JLabel insult = new JLabel((g.beginningList[g.beginning] + g.secondList[g.second] + g.fourthList[g.fourth] + g.thirdList[g.third] + g.endingList[g.ending]),SwingConstants.CENTER);
            insult.setBounds(0, 38, 300, 25);
            g.frame.add(insult);
        } else {
            JLabel insult = new JLabel((g.beginningList[g.beginning] + g.firstList[g.first] + g.secondList[g.second] + g.fourthList[g.fourth] + g.thirdList[g.third] + g.endingList[g.ending]),SwingConstants.CENTER);
            insult.setBounds(0, 38, 300, 25);
            g.frame.add(insult);
        } 
    }

    static class Action extends generate implements ActionListener {
        generate g = new generate();
        public void actionPerformed(ActionEvent e) {
            //what happens when the button is clicked

            randomize();

            if(g.beginning == 0) {
                JLabel insult = new JLabel((g.beginningList[g.beginning] + g.secondList[g.second] + g.fourthList[g.fourth] + g.thirdList[g.third] + g.endingList[g.ending]),SwingConstants.CENTER);
                insult.setBounds(0, 38, 300, 25);
                g.frame.add(insult);
            } else {
                JLabel insult = new JLabel((g.beginningList[g.beginning] + g.firstList[g.first] + g.secondList[g.second] + g.fourthList[g.fourth] + g.thirdList[g.third] + g.endingList[g.ending]),SwingConstants.CENTER);
                insult.setBounds(0, 38, 300, 25);
                g.frame.add(insult);
            }
        }
    }

    public static void randomize() {
        //regenerate the random numbers in generate()

        generate g = new generate();

        g.beginning = g.begin.nextInt(2);
        g.first = g.one.nextInt(3);
        g.second = g.two.nextInt(5);
        g.third = g.three.nextInt(23);
        g.fourth = g.four.nextInt(14);
        g.ending = g.end.nextInt(3);

    }
}

这是我的 generate() class 代码：

    import java.util.Random;

    import javax.swing.JFrame;
    public class generate {

        JFrame frame = new JFrame("Insult Generator");

        Random begin = new Random();
        int beginning = begin.nextInt(2);

        Random one = new Random();
        int first = one.nextInt(3);

        Random two = new Random();
        int second = two.nextInt(5);

        Random three = new Random();
        int third = three.nextInt(23);

        Random four = new Random();
        int fourth = four.nextInt(14);

        Random end = new Random();
        int ending = end.nextInt(3);

        String[] beginningList = {"You ", "Your "};
        String[] firstList = {"parents ", "friends ", "grandparents "};
        String[] secondList = {"are ", "smell ", "look ", "sound ", "act "};
        String[] thirdList = {"bad", "dumb", "ugly", "stupid", "fat", "terrible", "crappy", "poopy", "weird", "horrible", "atrocious", "awful", "gross", "substandard", "yucky", "unacceptable", "smelly", "rancid", "annoying", "disturbing", "creepy", "idiotic", "lame"};
        String[] fourthList = {"", "very ", "really ", "extremely ", "pretty ", "actually ", "quite ", "too ", "totally ", "strikingly ", "immensely ", "so ", "way too ", "kinda "};
        String[] endingList = {".", "!", "..."};
    }

同样，问题是 randomize() 方法没有改变变量的值。 抱歉，如果我提供的代码超出了必要的范围，但我认为这总比不够好...提前致谢！

Answer 1

您的问题是，您在每种方法中都创建了 Generate object，最终它对在主 class 中创建的 Generate object 没有任何影响。 尝试将 main 方法中创建的 Generate object 传递给 Action class 并随机化

Randomize - method

  public static void randomize(Generate g) {
    //reGenerate the random numbers in Generate()


    g.beginning = g.begin.nextInt(2);
    g.first = g.one.nextInt(3);
    g.second = g.two.nextInt(5);
    g.third = g.three.nextInt(23);
    g.fourth = g.four.nextInt(14);
    g.ending = g.end.nextInt(3);

}

Action

    static class Action extends Generate implements ActionListener {
    Generate g = null;
    public Action(Generate g) {
        this.g = g;
    } 
    ….
    …
   }

'从主创建动作'

button.addActionListener(new Action(g));

Answer 2

是的，您正在创建新的 generate 实例，而不是使用相同的 object。 您可以将 g 作为参数传递，但是将声明放在方法之外会给它们更多的 scope 以便可以在方法之外（从您的内部类）访问它们。 我不得不在 Java 201 课程中做这样的项目。

另外请记住 DRY 原则：不要重复自己。 意思是代码片段。 见下文，它仍然需要一些重构/重命名，但它解决了手头的问题，让你朝着更好的方向前进......

侮辱生成器：

import java.awt.Dimension;
import java.awt.event.*;
// you're not using Random here
//import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingConstants;

public class insultGenerator {
   // place the declarations of generate and insult here so that you can access in your inner class...
   static generate g;
   static JLabel insult;

   public static void main(String args[]) {
      // ...and create them here
      g = new generate();
      insult = new JLabel("", SwingConstants.CENTER);

      // put your gui initializations in one spot, and they only get called once instead of after each button fire
      g.frame.setLayout(null);
      g.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      g.frame.setPreferredSize(new Dimension(300, 200));
      g.frame.setLocationRelativeTo(null);
      g.frame.pack();
      g.frame.setVisible(true);

      insult.setBounds(0, 38, 300, 25);
      g.frame.add(insult);

      JButton button = new JButton("Generate New Insult");
      button.setBounds(75, 100, 150, 40);
      button.addActionListener(new Action());
      g.frame.add(button);

      // generate your first words
      button.doClick();
   }

   static class Action extends generate implements ActionListener {
      // here you were just creating a whole new g, NOT the same g that you are working with
      //generate g = new generate();

      public void actionPerformed(ActionEvent e) {
         // what happens when the button is clicked

         g.randomize();
         if(g.beginning == 0) {
            insult.setText(g.beginningList[g.beginning] + g.secondList[g.second] + g.fourthList[g.fourth]
                  + g.thirdList[g.third] + g.endingList[g.ending]);
         }
         else {
            insult.setText(g.beginningList[g.beginning] + g.firstList[g.first] + g.secondList[g.second]
                  + g.fourthList[g.fourth] + g.thirdList[g.third] + g.endingList[g.ending]);
         }
      }
   }
}

产生：

import java.util.Random;

import javax.swing.JFrame;

public class generate {
   // declare and initialize variables
   JFrame frame;
   int beginning = 0, first = 0, second = 0, third = 0, fourth = 0, ending = 0;

   String[] beginningList = { "You ", "Your " };
   String[] firstList = { "parents ", "friends ", "grandparents " };
   String[] secondList = { "are ", "smell ", "look ", "sound ", "act " };
   String[] thirdList = { "bad", "dumb", "ugly", "stupid", "fat", "terrible", "crappy", "poopy", "weird", "horrible",
         "atrocious", "awful", "gross", "substandard", "yucky", "unacceptable", "smelly", "rancid", "annoying",
         "disturbing", "creepy", "idiotic", "lame" };
   String[] fourthList = { "", "very ", "really ", "extremely ", "pretty ", "actually ", "quite ", "too ", "totally ",
         "strikingly ", "immensely ", "so ", "way too ", "kinda " };
   String[] endingList = { ".", "!", "..." };

   // create a constructor, it's good practice
   public generate() {
      frame = new JFrame("Insult Generator");
   }

   // Just call this method to generate new numbers/words.
   // Cleaned up unnecessary extra objects, just use the same instance of Random.
   public void randomize() {
      Random random = new Random();
      // automatically get the size, so when you add new words to the list you don't need to edit here
      beginning = random.nextInt(beginningList.length);
      first = random.nextInt(firstList.length);
      second = random.nextInt(secondList.length);
      third = random.nextInt(thirdList.length);
      fourth = random.nextInt(firstList.length);
      ending = random.nextInt(endingList.length);
   }
}

题外话，但您可能希望调整按钮的宽度，这是我在 Linux 上的显示方式：