额外单击即可在Jframe中的页面之间导航

Question

这是我为解码24位tiff文件而编写的代码。

package decoding.tiff;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferInt;
import java.io.RandomAccessFile;
import java.util.ArrayList;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;

public class TiffMultiPage24Bit extends javax.swing.JFrame implements
        ActionListener {

    private static final long serialVersionUID = -4935096415846083312L;

    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JButton jLabel1;
    JScrollPane logScrollPane;

    static ArrayList<BufferedImage> images = new ArrayList<BufferedImage>();
    static int count = 0;
    static int minvalue = -1;
    static int totalimages = 0;

    public TiffMultiPage24Bit() {
        initComponents();

        jButton1.addActionListener(this);
        jButton2.addActionListener(this);

    }

    private void initComponents() {
//Code for frame view
    }

    @SuppressWarnings({ "resource", "unused" })
    public static void main(String args[]) throws Throwable {


        {

        //Code for image decoding

            images.add(buff); // adding the image to array list

        }

        totalimages = images.size();

        TiffMultiPage24Bit mp = new TiffMultiPage24Bit();

        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new TiffMultiPage24Bit().setVisible(true);
            }
        });

    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == jButton1) {
            count--;
            if (count > minvalue) {
                jLabel1.setIcon(new ImageIcon(images.get(count)));
            } else {
                JOptionPane.showMessageDialog(null, "No Previous Image");
            }
        }

        if (e.getSource() == jButton2) {
            count++;
            if (count < totalimages) {
                jLabel1.setIcon(new ImageIcon(images.get(count)));
            } else {
                JOptionPane.showMessageDialog(null, "No Next Image");
            }
        }

    }

}

当我第一次单击“ next”时，它工作正常。

但是一旦转到最后一页，则需要两次单击才能返回到上一页....而转到第一页时，则需要单击两次以转到下一页。...

请帮助...。任何帮助将不胜感激...

Answer 1

当count无效时，您需要将count恢复为最大允许值

这样想吧...

• 您单击下一步
• count增加
• count > = totalimages ，显示错误消息（ count现在等于（至少） totalimages
• 点击上一个
• count递减，现在等于totalimages - 1 ，这是最后一个（和当前的）图像...

每次count无效时，您需要将其重置回有效范围...

if (e.getSource() == jButton1) {
    count--;
    if (count > minvalue) {
        //...
    } else {
        count = minvalue;
        //...
    }
} else if (e.getSource() == jButton2) {
    count++;
    if (count < totalimages) {
        //...
    } else {
        count = totalimages - 1;
        //...
    }
}

举个例子

很棒的是，您现在拥有的方式是，我可以继续单击“下一步”并继续增加count数值...当count达到上限或下限时，甚至可能值得禁用按钮...

Answer 2

或者...我在代码中这样更改它.....

public void actionPerformed(ActionEvent e) {

    if (e.getSource() == jButton1) {
        count--;
        if(count==minvalue || count<minvalue)
        {
            JOptionPane.showMessageDialog(null, "No Previous Image");
            count=minvalue+1;
        }
        if (count > minvalue && count < totalimages) {
            jLabel1.setIcon(new ImageIcon(images.get(count)));
        } 
    }

    if (e.getSource() == jButton2) {
        count++;
        if(count==totalimages || count >totalimages)
        {
            count=totalimages-1;

            JOptionPane.showMessageDialog(null, "No Next Image");
        }
        if (count < totalimages && count > minvalue) {
            jLabel1.setIcon(new ImageIcon(images.get(count)));
        } 
    }
}