的Java：在jscrollpanne

Question

我有一些问题whene我想加载图像

1类加载图像：Draw_Image

import java.awt.*; 
import java.awt.image.BufferedImage; 
import javax.imageio.ImageIO; 
import java.io.*; 

public class Draw_Image extends Canvas{ 
    BufferedImage image= null; 
    //Constructeur, prend une image Buffered 
    public Draw_Image(BufferedImage img){ 
     //copier l'image dans son attribut 
     image= img; 
    } 
    public void paint(Graphics g){ 
     //Peintre le graphique g d e l'image 
     g.drawImage(image,0,0,this); 
    } 
} 

2类：选择一个图像和我尝试加载Jscrollpan（以申报主CLAS）

import java.awt.BorderLayout; 
import java.awt.image.BufferedImage; 
import java.io.File; 
import java.io.IOException; 
import javax.imageio.ImageIO; 
import javax.swing.JFileChooser; 
import javax.swing.JPanel; 

public class LoadImage extends JPanel{ 
    private String path1; 
    private String path2; 
    private String path3; 
    NewJFrame j; 

    private JFileChooser parcourir= new JFileChooser(); 

    BufferedImage img = null; 

    public LoadImage(){ 
     parcourir.showOpenDialog(null); 
     if(parcourir.showOpenDialog(null)== JFileChooser.APPROVE_OPTION){ 
      //récupérer image à partir du choix de l'utilisateur 
      String file2= parcourir.getSelectedFile().getPath(); 
      path2= file2; 

      try { 
       img = ImageIO.read(new File(file2)); 
       Draw_Image d1= new Draw_Image(img);   
       //d1.setSize(j.jScrollPane1.getWidth(),j.jScrollPane1.getHeight()); 

       j.jScrollPane1.removeAll(); 
       j. jScrollPane1.add(d1);  
       add(d1, BorderLayout.CENTER); 
      } 
      catch (IOException ex) { 
       // Logger.getLogger(NewJFrame.class.getName()).log(Level.SEVERE, null, ex); 
       System.out.println("err"); 
      } 
     } 
    } 
} 

主类

public class Main extends javax.swing.JFrame { 

/** 
* Creates new form NewJFrame 
*/ 
public Main() { 
    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() { 

    jScrollPane1 = new javax.swing.JScrollPane(); 
    jButton_Open_Image = new javax.swing.JButton(); 
    jButton2 = new javax.swing.JButton(); 
    jMenuBar1 = new javax.swing.JMenuBar(); 
    jMenu1 = new javax.swing.JMenu(); 
    jMenu2 = new javax.swing.JMenu(); 

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); 

    jButton_Open_Image.setText("Open"); 
    jButton_Open_Image.addActionListener(new java.awt.event.ActionListener() { 
     public void actionPerformed(java.awt.event.ActionEvent evt) { 
      jButton_Open_ImageActionPerformed(evt); 
     } 
    }); 

    jButton2.setText("Gray_Scale"); 

    jMenu1.setText("File"); 
    jMenuBar1.add(jMenu1); 

    jMenu2.setText("Edit"); 
    jMenuBar1.add(jMenu2); 

    setJMenuBar(jMenuBar1); 

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); 
    getContentPane().setLayout(layout); 
    layout.setHorizontalGroup(
     layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
     .addGroup(layout.createSequentialGroup() 
      .addContainerGap() 
      .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
       .addComponent(jButton2) 
       .addComponent(jButton_Open_Image, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)) 
      .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED) 
      .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 283, Short.MAX_VALUE) 
      .addContainerGap()) 
    ); 
    layout.setVerticalGroup(
     layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
     .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup() 
      .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
      .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 264, javax.swing.GroupLayout.PREFERRED_SIZE) 
      .addContainerGap()) 
     .addGroup(layout.createSequentialGroup() 
      .addGap(53, 53, 53) 
      .addComponent(jButton_Open_Image) 
      .addGap(18, 18, 18) 
      .addComponent(jButton2) 
      .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)) 
    ); 

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

private void jButton_Open_ImageActionPerformed(java.awt.event.ActionEvent evt) {             
    new LoadImage(); 
}             

/** 
* @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(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 
    } catch (InstantiationException ex) { 
     java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 
    } catch (IllegalAccessException ex) { 
     java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 
    } catch (javax.swing.UnsupportedLookAndFeelException ex) { 
     java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 
    } 
    //</editor-fold> 
    //</editor-fold> 

    /* Create and display the form */ 
    java.awt.EventQueue.invokeLater(new Runnable() { 
     public void run() { 
      new Main().setVisible(true); 
     } 
    }); 
} 

// Variables declaration - do not modify      
private javax.swing.JButton jButton2; 
private javax.swing.JButton jButton_Open_Image; 
private javax.swing.JMenu jMenu1; 
private javax.swing.JMenu jMenu2; 
private javax.swing.JMenuBar jMenuBar1; 
protected javax.swing.JScrollPane jScrollPane1; 

enter image description here

谢谢。

Answer 1

切勿使用add（...）方法将组件添加到JScrollPane。组件需要添加到滚动面板的JViewport。

JScrollPane scrollPane = new JScrollPane(someComponent); 

，或者您可以使用：

这是当你使用创建一个JScrollPane自动完成

scrollPane.setViewportView(someComponent); 

如果你想显示的图像，也没有必要做的风俗画。只需添加一个ImageIcon到JLabel和标签添加到滚动窗格

JLabel label = new JLabel(new ImageIcon(...)); 
JScrollPane scrollPane = new JScrollPane(label); 

如果你想要做的风俗画的不延伸帆布，这是一个AWT组件。相反，您可以扩展JPanel。当您扩展JPanel时，您需要重写paintComponent(...)并实施getPreferredSize()以使滚动窗格正常工作。

有关更多信息，请参阅Swing教程中关于Custom Painting的部分。保留所有Swing基础知识的教程的链接。

本教程还有一个关于How to Use Icons的部分，您应该阅读。