我对GUI构建比较陌生。
我想用一个按钮（我已经拥有）创建一个GUI，用户可以按下并选择一个图像，然后动态地将该图像加载到面板的GUI中。 我希望每次用户浏览图像时动态更改图像。
到目前为止，我的代码是......但我无法将按钮连接到JPanel或其他东西。
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.swing.*;
public class WebAppImg extends javax.swing.JFrame {
private int image_height;
private int image_aspect_ratio;
private Graphics2D engine;
private JLabel photoComponent;
/**
* Creates new form WebAppImg
*/
public WebAppImg() {
initComponents();
}
/**
* 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")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jButton1 = new javax.swing.JButton();
jTextField1 = new javax.swing.JTextField();
jLabel1 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setPreferredSize(new java.awt.Dimension(600, 480));
jButton1.setText("Attach");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jTextField1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jTextField1ActionPerformed(evt);
}
});
jLabel1.setText("label2");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(21, 21, 21)
.addComponent(jButton1)
.addGap(154, 154, 154)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 239, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(133, Short.MAX_VALUE))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 199, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(120, 120, 120))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addGap(57, 57, 57)
.addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 163, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 141, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(35, 35, 35))
);
pack();
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
JFileChooser chooser = new JFileChooser();
JLabel label2 = new JLabel();
JInternalFrame jInternalFrame1 = new JInternalFrame();
chooser.showOpenDialog(null);
File f = chooser.getSelectedFile();
String filename = f.getAbsolutePath();
jTextField1.setText(filename);
jInternalFrame1.getDesktopIcon();
}
private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* 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(WebAppImg.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(WebAppImg.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(WebAppImg.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(WebAppImg.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 WebAppImg().setVisible(true);
}
});
//Create a file chooser
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
private javax.swing.JTextField jTextField1;
// End of variables declaration
}
答案 0 :(得分：3)
我认为你想要的是要显示的所选图像，如果这样改变了你的jButton1ActionPerformed方法：
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
JFileChooser chooser = new JFileChooser();
chooser.showOpenDialog(null);
File f = chooser.getSelectedFile();
String filename = f.getAbsolutePath();
jTextField1.setText(filename);
try {
ImageIcon ii=new ImageIcon(scaleImage(120, 120, ImageIO.read(new File(f.getAbsolutePath()))));//get the image from file chooser and scale it to match JLabel size
jLabel1.setIcon(ii);
} catch (Exception ex) {
ex.printStackTrace();
}
}
public static BufferedImage scaleImage(int w, int h, BufferedImage img) throws Exception {
BufferedImage bi;
bi = new BufferedImage(w, h, BufferedImage.TRANSLUCENT);
Graphics2D g2d = (Graphics2D) bi.createGraphics();
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY));
g2d.drawImage(img, 0, 0, w, h, null);
g2d.dispose();
return bi;
}
更好的解决方案是看到您使用SwingWorker加载图片，以便UI不会无响应（如果图片很大）：
private ImageIcon ii;
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
JFileChooser chooser = new JFileChooser();
chooser.showOpenDialog(null);
final File f = chooser.getSelectedFile();
String filename = f.getAbsolutePath();
if (f == null) {
return;
}
jTextField1.setText(filename);
SwingWorker sw = new SwingWorker() {
@Override
protected Object doInBackground() throws Exception {
Thread.sleep(5000);//simulate large image takes long to load
ii = new ImageIcon(scaleImage(120, 120, ImageIO.read(new File(f.getAbsolutePath()))));
return null;
}
@Override
protected void done() {
super.done();
jLabel1.setIcon(ii);
}
};
sw.execute();
}