Java：讀取目錄數組以顯示目錄中包含的圖像，以便能夠在數組中前后移動

Question

您好，感謝您的提前協助。

我的目標是加載一個名為resource的目錄以創建一個數組。 這樣做之后，程序應使用“下一個”和“上一個”按鈕通過使用計數器在數組中前后循環。 遍歷數組應該顯示適當的圖片（不知道圖片是什么，只是圖片在數組中的順序）。

到目前為止，我的代碼：

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JLabel;
import javax.swing.JButton;
import javax.swing.BoxLayout;
import javax.swing.JTextField;
import java.io.IOException;
import javax.swing.ImageIcon;    
import java.io.*;
import java.util.*;
import java.nio.file.Files;
import java.nio.file.Paths;        
import java.awt.*;
import java.awt.event.*;

public class viewer extends JFrame implements ActionListener
{
    int counter = 0; //Initial counter value
    int maxItems = 0; // Set it equal to the length of the array
    int minItems = 0; //Minimum items for previous button

    JPanel botPanel = null;
    JPanel midPanel = null;
    JLabel midLabel = null;

    ImageIcon image;

    String[] picture = new String [1000];

    public viewer()
    {
        setTitle ("Roberts Viewer");
        setSize (1000, 1000);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Allow the X button to close the program and not just the frame
        JPanel midPanel = new JPanel ();
        JPanel botPanel = new JPanel ();

        midLabel = new JLabel();


        JButton prv = new JButton("Previous"); botPanel.add(prv); prv.addActionListener(this);
        JButton nxt = new JButton("Next"); botPanel.add(nxt); nxt.addActionListener(this);
        JButton quitButton = new JButton ("Quit Program"); botPanel.add(quitButton); quitButton.addActionListener(this);

        add(midPanel, BorderLayout.CENTER);
        add(botPanel, BorderLayout.SOUTH);

        File dir = new File ("resource");
        File[] picture = dir.listFiles();

        for (int maxItems = 0;maxItems < picture.length; maxItems++);

        midPanel.add(midLabel);

        setVisible(true);
    }   

    public static void main(String[] args)
    {
        viewer v = new viewer();
    }

    public void actionPerformed (ActionEvent e) 
    {
        String action = e.getActionCommand();

        if (action.equals("Quit Program"))
        {
            System.exit(0);
        }

        if(action.equals("Next"))
        {
            if (counter < 0){counter = 0;}
            if (counter> maxItems) {counter = 0;}

            String pictureString = String.format("resource/%s", picture[counter]);
            System.out.printf("Retrieving[%s]\n",pictureString);

            try
            {
                image = new ImageIcon(getClass().getClassLoader().getResource(pictureString));
            }
            catch (Exception xu)
            {
                System.out.println("Woops");
            }

            midLabel.setIcon(image);
            counter++;
        }

        if(action.equals("Previous"))
        {
            if (counter < 0) {counter = maxItems;}
            if (counter < minItems) {counter = maxItems;}

            String pictureString = String.format("resource/%s",picture[counter]);
            System.out.printf("Retrieving[%s]\n", pictureString);

            try
            {
                image = new ImageIcon(getClass().getClassLoader().getResource(pictureString));
            }
            catch (Exception xu)
            {
                System.out.println("Woops");
            }

            midLabel.setIcon(image);
            counter--;
        }
    }
}

Answer 1

問題解決了。 我有一些錯誤，但這是固定的代碼。 導入javax.swing.JFrame; 導入javax.swing.JPanel; 導入javax.swing.JLabel; 導入javax.swing.JButton; 導入javax.swing.BoxLayout; 導入javax.swing.JTextField;

    import java.io.IOException;

    import javax.swing.ImageIcon;

    import java.io.*;
    import java.util.*;
    import java.nio.file.Files;
    import java.nio.file.Paths;

    import java.awt.*;
    import java.awt.event.*;


    public class viewer extends JFrame implements ActionListener
    {
        int counter = 0; //Initial counter value
        int maxItems = 0; // Set it equal to the length of the array
        int minItems = 0; //Minimum items for previous button

        JPanel botPanel = null;
        JPanel midPanel = null;
        JLabel midLabel = null;


        ImageIcon image;

        File[] picture;


        public viewer()
        {
            setTitle ("Roberts Viewer");
            setSize (500, 500);
            setLocationRelativeTo(null);
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            JPanel midPanel = new JPanel ();
            JPanel botPanel = new JPanel ();

            midLabel = new JLabel();


            JButton prv = new JButton("Previous"); botPanel.add(prv); prv.addActionListener(this);
            JButton nxt = new JButton("Next"); botPanel.add(nxt); nxt.addActionListener(this);
            JButton quitButton = new JButton ("Quit Program"); botPanel.add(quitButton); quitButton.addActionListener(this);

            add(midPanel, BorderLayout.CENTER);
            add(botPanel, BorderLayout.SOUTH);


            File dir = new File ("resource");
            picture = dir.listFiles();
            midPanel.add(midLabel);
            image = new ImageIcon("resource/"+picture [0].getName());
            midLabel.setIcon(image);
            setVisible(true);
        }   
            public static void main(String[] args)
        {
            viewer v = new viewer();
        }

        public void actionPerformed (ActionEvent e) 
        {
            String action = e.getActionCommand();
            if (action.equals("Quit Program"))
            {
                System.exit(0);
            }
            if(action.equals("Next"))
            {
                counter++;
                if (counter>= picture.length) {counter = 0;}

                try
                {
                    image = new ImageIcon("resource/"+picture[counter].getName());
                    midLabel.setIcon(image);

                }
                catch (Exception xu)
                {
                    System.out.println("Woops");
                }


                System.out.printf("Exit next: " + counter + "\n");
            }
            if(action.equals("Previous"))
            {
                counter--;
                if (counter < 0) {counter = picture.length-1;}
            String.format("resource/%s",picture[counter].getName());

                try
                {
                    image = new ImageIcon("resource/"+picture[counter].getName());
                    midLabel.setIcon(image);

                }
                catch (Exception xu)
                {
                    System.out.println("Woops");
                }


                System.out.printf("Exit prev: " + counter + "\n");
            }
        }
    }