java - 如何在 Java GUI 中更新图像

Question

我有一个带有多个按钮的 GUI，我正在使用 NetBeans GUI Builder 来执行此操作。单击其中一个时，我希望它打开另一个包含图片的框架。

因此，我将一个监听器 (actionPerformed) 与按钮关联起来，当单击它时，它实际上会打开并发布新帧。

在新框架中，我给 JLabel 打蜡，然后关联标签的图像。我看到 NetBeans 会生成以下代码:

label.setIcon(new javax.swing.ImageIcon(getClass().getResource("/img/tree.png")));

我的问题是在程序执行过程中图片被覆盖多次，但框架中尚未更改。也就是说，在新帧中始终显示旧版本的图像。

如何才能使图像始终保持最新？非常感谢

<小时/>

代码:

package View;

import Controller.Util;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JLabel;

public class AlberoIpotesi extends javax.swing.JFrame {

   /** Creates new form AlberoIpotesi */
   public AlberoIpotesi() {
      initComponents();

      remove(label);
      revalidate(); 
      repaint();
      Decifra.sessioneDec.toString(".../src/img/tree");
      revalidate(); 
      repaint();
   }

   /** 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() {

      jLabel1 = new javax.swing.JLabel();
      scroll = new javax.swing.JScrollPane();
      label = new javax.swing.JLabel();

      setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
      setTitle("Albero delle ipotesi");

      jLabel1.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
      jLabel1.setText("Albero delle ipotesi");

      label.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
      label.setIcon(new javax.swing.ImageIcon(getClass().getResource("/Img/tree.png"))); // NOI18N
      label.setVerticalAlignment(javax.swing.SwingConstants.TOP);
      scroll.setViewportView(label);

      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(29, 29, 29)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
               .addComponent(scroll, javax.swing.GroupLayout.PREFERRED_SIZE, 342, javax.swing.GroupLayout.PREFERRED_SIZE)
               .addComponent(jLabel1))
            .addContainerGap(29, Short.MAX_VALUE))
      );
      layout.setVerticalGroup(
         layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
         .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jLabel1)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
            .addComponent(scroll, javax.swing.GroupLayout.PREFERRED_SIZE, 374, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(25, Short.MAX_VALUE))
      );

      pack();
   }// </editor-fold>                        

   /**
    * @param args the command line arguments
    */
   public static void start() {
      /* 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(AlberoIpotesi.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
      } catch (InstantiationException ex) {
         java.util.logging.Logger.getLogger(AlberoIpotesi.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
      } catch (IllegalAccessException ex) {
         java.util.logging.Logger.getLogger(AlberoIpotesi.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
      } catch (javax.swing.UnsupportedLookAndFeelException ex) {
         java.util.logging.Logger.getLogger(AlberoIpotesi.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 AlberoIpotesi().setVisible(true);
         }
      });
   }

   // Variables declaration - do not modify                     
   private javax.swing.JLabel jLabel1;
   public static javax.swing.JLabel label;
   public static javax.swing.JScrollPane scroll;
   // End of variables declaration                   
}

Answer 1

我将 JLabel 上的图标和 setIcon 的创建分开，如下所示:

ImageIcon icon = new ImageIcon("path/to/picture.png");
label.setIcon(icon);

这样您就可以稍后更改图标的图像并更新标签

icon = new ImageIcon("path/to/new_picture.png"); // Changes the icon
label.setIcon(icon); // Updates the label's icon