在Java中动态添加ImageIcon

Question

好吧，我是GUI方面的新手。我正在试验一个简单的程序，你选择一个颜色，宽度，高度，它会生成一个具有指定值的png文件。我的问题是在我的生成函数执行后将图像图标添加到标签。文件已经创建，但是imageIcon没有显示在imagePanel中。这只是我创建的一个测试。

这就是我遇到麻烦的地方:

    private void generateActionPerformed(java.awt.event.ActionEvent evt) {                                    
    int Width=getWidthInput();
    int Height= getHeightInput();
    BufferedImage image= new BufferedImage(Width,Height, BufferedImage.TYPE_INT_ARGB);
    File directory= null;
    BufferedImage generatedPic;
    //drawing portions of image
    for(int i = 0; i < Height; i++){
            for(int j=0; j<Width; j++){
                    int a=255;
                    int r=getRed();
                    int g=getGreen();
                    int b=getBlue();
                    int p= (a<<24)|(r<<16)|(g<<8)|b;
                    image.setRGB(j,i,p);
            }
    }
    try{
            directory= new File("testImg.png");
            ImageIO.write(image,"png",directory);
            System.out.println("Image Has Been Written");
            ImageIcon ii= new ImageIcon(getClass().getResource("testImg.png"));
            imageLabel.setIcon(ii);
            revalidate();
            repaint();
    }
    catch(IOException e){
            System.out.println("Error: "+ e);
    }
    directory.deleteOnExit();   
}

这是整个程序:

public class MainFrame extends javax.swing.JFrame {
    private JButton submitBtn;
    /**
     * Creates new form MainFrame
     */
    public MainFrame() {
        initComponents();
    }
    public int getRed(){
        return Integer.parseInt(red.getText());
    }
    public int getGreen(){
        return Integer.parseInt(green.getText());
    }
    public int getBlue(){
        return Integer.parseInt(blue.getText());
    }
    public int getWidthInput(){
        return Integer.parseInt(width.getText());
    }
    public int getHeightInput(){
        return Integer.parseInt(height.getText());
    }
    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    private void initComponents() {
        mainPanel = new javax.swing.JPanel();
        imagePanel = new javax.swing.JPanel();
        imageLabel= new JLabel();

        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        jLabel4 = new javax.swing.JLabel();
        red = new javax.swing.JTextField();
        green = new javax.swing.JTextField();
        blue = new javax.swing.JTextField();
        width = new javax.swing.JTextField();
        height = new javax.swing.JTextField();
        jMenuBar1 = new javax.swing.JMenuBar();
        jMenu1 = new javax.swing.JMenu();
        jMenu2 = new javax.swing.JMenu();
        jMenu3 = new javax.swing.JMenu();
        submitBtn= new JButton("Generate Image");
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        mainPanel.setForeground(new java.awt.Color(54, 136, 137));
        mainPanel.setAutoscrolls(true);


        jLabel2.setText("color:");
        jLabel3.setText("width:");
        jLabel4.setText("height:");
        submitBtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                generateActionPerformed(evt);
            }
        });
        javax.swing.GroupLayout imagePanelLayout = new javax.swing.GroupLayout(imagePanel);
        imagePanel.setLayout(imagePanelLayout);
        imagePanelLayout.setHorizontalGroup(
            imagePanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(imageLabel, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 446, Short.MAX_VALUE)
        );
        imagePanelLayout.setVerticalGroup(
            imagePanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(imageLabel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        javax.swing.GroupLayout mainPanelLayout = new javax.swing.GroupLayout(mainPanel);
        mainPanel.setLayout(mainPanelLayout);
        mainPanelLayout.setHorizontalGroup(
            mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, mainPanelLayout.createSequentialGroup()
                .addContainerGap()
                .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                        .addComponent(jLabel2)
                        .addComponent(jLabel3))
                    .addComponent(jLabel4))
                .addGap(18, 18, 18)
                .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addGroup(mainPanelLayout.createSequentialGroup()
                        .addComponent(red, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(green, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(blue, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addComponent(width)
                    .addComponent(height)
                    .addComponent(submitBtn))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 43, Short.MAX_VALUE)
                .addComponent(imagePanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        mainPanelLayout.setVerticalGroup(
            mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(imagePanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addGroup(mainPanelLayout.createSequentialGroup()
                .addGap(50, 50, 50)
                .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2)
                    .addComponent(red, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(green, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(blue, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel3)
                    .addComponent(width, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel4)
                    .addComponent(height, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(submitBtn, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(297, Short.MAX_VALUE))
        );
        jMenuBar1.setBackground(new java.awt.Color(54, 136, 137));
        jMenu1.setText("File");
        jMenuBar1.add(jMenu1);
        jMenu2.setText("Edit");
        jMenuBar1.add(jMenu2);
        jMenu3.setText("jMenu3");
        jMenuBar1.add(jMenu3);
        setJMenuBar(jMenuBar1);
        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(mainPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(mainPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        pack();
    }
    private void generateActionPerformed(java.awt.event.ActionEvent evt) {                                    
        int Width=getWidthInput();
        int Height= getHeightInput();
        BufferedImage image= new BufferedImage(Width,Height, BufferedImage.TYPE_INT_ARGB);
        File directory= null;
        BufferedImage generatedPic;
        //drawing portions of image
        for(int i = 0; i < Height; i++){
                for(int j=0; j<Width; j++){
                        int a=255;
                        int r=getRed();
                        int g=getGreen();
                        int b=getBlue();
                        int p= (a<<24)|(r<<16)|(g<<8)|b;
                        image.setRGB(j,i,p);
                }
        }
        try{
                directory= new File("testImg.png");
                ImageIO.write(image,"png",directory);
                System.out.println("Image Has Been Written");
                ImageIcon ii= new ImageIcon(getClass().getResource("testImg.png"));
                imageLabel.setIcon(ii);
                revalidate();
                repaint();
        }
        catch(IOException e){
                System.out.println("Error: "+ e);
        }
        directory.deleteOnExit();


    }     


/*    
    private void redActionPerformed(java.awt.event.ActionEvent evt) {                                    
        // TODO add your handling code here:
    }                                   
*/
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) throws IOException {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(MainFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(MainFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(MainFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(MainFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new MainFrame().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify                     
    private javax.swing.JTextField blue;
    private javax.swing.JTextField green;
    private javax.swing.JTextField height;
    private javax.swing.JLabel imageLabel;
    private javax.swing.JPanel imagePanel;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JMenu jMenu1;
    private javax.swing.JMenu jMenu2;
    private javax.swing.JMenu jMenu3;
    private javax.swing.JMenuBar jMenuBar1;
    private javax.swing.JPanel mainPanel;
    private javax.swing.JTextField red;
    private javax.swing.JTextField width;
    // End of variables declaration                   
}

Answer 1

由于代码已经创建了一个File，因此使用该文件作为ImageIcon的URL的基础是完全有意义的!如

import java.awt.image.BufferedImage;
import java.io.*;
import java.net.MalformedURLException;
import javax.imageio.ImageIO;
import javax.swing.*;
public class SavedImageDisplayer {
    public static void main(String[] args) throws IOException {
        BufferedImage img = new BufferedImage(200, 100, BufferedImage.TYPE_INT_RGB);
        final File file = new File("testImg.png");
        ImageIO.write(img, "png", file);
        Runnable r = new Runnable() {
            @Override
            public void run() {
                ImageIcon imageIcon;
                try {
                    // use the File as basis for the URL!
                    imageIcon = new ImageIcon(file.toURI().toURL());
                    JOptionPane.showMessageDialog(null, imageIcon);
                } catch (MalformedURLException ex) {
                    ex.printStackTrace();
                }
            }
        };
        SwingUtilities.invokeLater(r);
    }
}