java - 图像不断重复，尽管它已经是随机的

Question

我正在开发一个简单的游戏，其中所有图像都是随机的。我注意到尽管我输入了随机代码，但有些图像是重复的。我对 Java 还是个新手。我希望有人能帮助我解决我的问题。下面是我的编码。

import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import java.util.Random;
import javax.swing.*;

public class Task1 extends JFrame implements KeyListener,ActionListener {
    JFrame frame = new JFrame("FYP");
    JTextField textField = new JTextField();
    JButton btnNext = new JButton("NEXT"); 

    int sum=0;
    int Error=0;int total_test = 0;
    static String inputID;
    static int index;
    String[] imgFileHP = {"1.jpg","3.jpg","4.jpg","7.jpg","9.jpg","10.jpg","12.jpg","16.jpg","17.jpg","18.jpg"};
    String[] imgNo = {"5","4","6","3","5","3","4","4","6","6"};
    int randomNo;
    Random rand = new Random();

public Task1(String inputID)
{
    frame.setSize(2200,2500);
    frame.setLocationRelativeTo(null);  
    frame.setVisible(true);
    frame.getContentPane().setLayout(new BorderLayout(0, 0));       

    Task(inputID);
}

public void Task(String inputID)
{
    JPanel panel = new JPanel();
    JLabel labelUsername = new JLabel("");

    frame.getContentPane().add(panel, BorderLayout.CENTER);
    panel.setBackground(Color.WHITE);

    Collections.shuffle(Arrays.asList(imgFileHP));
    Set<Integer> uniqueList = new HashSet<Integer>();//This would create list with the number 0 to 9
    for(int count=0;count<imgFileHP.length;count++){
        uniqueList.add(count);
        labelUsername.setIcon(new ImageIcon(getClass().getResource("/image/" + imgFileHP[count])));
        if(!uniqueList.isEmpty()){
            index =  (int) (Math.random() * (upper - lower)) + lower;

            if(uniqueList.contains(index)){

               uniqueList.remove(index);//particular number is delete from the list so that duplicate images doesnt show up
               System.out.println(imgFileHP[r]);//This printf statement is just for your reference
            }   
        }


    }
    textField.setText("");
    textField.setColumns(10);
    textField.addKeyListener(this);     

    btnNext.addActionListener(this);

    panel.add(labelUsername);
    panel.add(textField);
    panel.add(btnNext);
    frame.setVisible(true);
}

public void actionPerformed(ActionEvent ae)
{

    if(!textField.getText().equals("")){
        total_test += 1;
        if(isNumeric(textField.getText())){
            //********************Correct Integer**********************
            if(Integer.valueOf(imgNo[randomNo])==Integer.valueOf(textField.getText())){
                //********************Correct Answer**********************
                System.out.println("Correct");
                sum+=1;
            }else{
                //********************Incorrect Answer**********************
                System.out.println("Incorrect");
                Error+=1;
            }
            refreshFrame();
        }else{
            //********************Incorrect Integer/Alphabet**********************
            System.out.println("Invalid");
            Error+=1;
            refreshFrame();
        }
    }else{
        System.out.println("Null Input");
    }
    //System.out.println(Integer.valueOf(imgNo[randomNo]));
}
public void refreshFrame(){
    if(total_test>=10){
        // add result page to see how many score
        //Task2(sum, Error);
        System.out.println("Correct: "+sum+" Incorrect: "+Error);
        frame.dispose();
    }else{
        btnNext.removeActionListener(this);
        frame.getContentPane().removeAll();
        getContentPane().removeAll();
        Task(inputID);
    }

}

    public static void main(String args[]) {
        Task1 a = new Task1(inputID);
    }
    @Override
    public void keyPressed(KeyEvent e) {
        // TODO Auto-generated method stub

    }
    @Override
    public void keyReleased(KeyEvent e) {
        // TODO Auto-generated method stub

    }
    @Override
    public void keyTyped(KeyEvent e) {
        // TODO Auto-generated method stub

    }

    public static boolean isNumeric(String str)  
    {  
      try  
      {  
          Integer.valueOf(str);  
      }  
      catch(NumberFormatException nfe)  
      {  
        return false;  
      }  
      return true;  
    }

}

编辑部分(但有些图像仍然重复。)

Collections.shuffle(Arrays.asList(imgFileHP));
    Set<Integer> uniqueList = new HashSet<Integer>();//This would create   list with the number 0 to 9
    for(int count=0;count<imgFileHP.length;count++){
        uniqueList.add(count);
    }

        if(!uniqueList.isEmpty()){
            index =  (int) (Math.random() * (upper - lower)) + lower;
            randomNo = index;
            if(uniqueList.contains(index)){
               labelUsername.setIcon(new ImageIcon(getClass().getResource("/image/" + imgFileHP[index]))); 
               uniqueList.remove(index);//particular number is delete from the list so that duplicate images doesnt show up
               System.out.println(imgFileHP[r]);//This printf statement is just for your reference
            }   
        }

Answer 1

这是随机的工作原理。即使您提到了rand.nextInt(10);，但每次调用它时，java中都没有预定义的规则，它必须生成唯一的数字，而不是与先前生成的数字重复。

例如:你打电话时 -int 索引 = rand.nextInt(10);//索引可以是2索引 = rand.nextInt(10);//现在该值也可以是 2

所以你需要做的是，你必须添加一段额外的代码来检查每次调用 random 时的唯一性。

既然你想生成0到10之间的数字，试试下面的代码，它可能会帮助你理解。

String[] imgFileHP = {"1.jpg","3.jpg","4.jpg","7.jpg","9.jpg","10.jpg","12.jpg","16.jpg","17.jpg","18.jpg"};
        int upper = imgFileHP.length;
        int lower = 0;
        int r=0;
        int index=0;

        Set<Integer> uniqueList = new HashSet<Integer>();//This would create list with the number 0 to 9
        for(int count=0;count<imgFileHP.length;count++){
            uniqueList.add(count);
        }



        if(!uniqueList.isEmpty()){
            index =  (int) (Math.random() * (upper - lower)) + lower;

            if(uniqueList.contains(index)){

                uniqueList.remove(index);//particular number is delete from the list so that duplicate images doesnt show up
                System.out.println(imgFileHP[r]);//This printf statement is just for your reference
            }   
        }

另一种更简单的方法是使用 Collections.Shuffle，如下所示:

Collections.shuffle(Arrays.asList(imgFileHP));

Collection.shuffle() 示例。

假设您有一个数组String[] arr = {"abc","def","xyz","bla"}

当你这样做时 Collections.shuffle(Arrays.asList(arr));

然后从索引 0 到 3 打印数组。数组可能会被打乱，如下所示:{"def","bla","abc","xyz"}

**编辑2:**基于您在主代码中编辑的解决方案:

  for(int count=0;count<imgFileHP.length;count++){//first add the counters into List 
            uniqueList.add(count);
        }


        if(!uniqueList.isEmpty()){
            index =  (int) (Math.random() * (upper - lower)) + lower;

            if(uniqueList.contains(index)){
               labelUsername.setIcon(new ImageIcon(getClass().getResource("/image/" + imgFileHP[index])));
               uniqueList.remove(index);//particular number is delete from the list so that duplicate images doesnt show up
               System.out.println(imgFileHP[r]);//This printf statement is just for your reference
            }   
        }