JPanel에 아무것도 표시되지 않습니다.

Question

JPanel 내부에 JComponent가 표시되지 않는데 문제가 있습니다.

Netbeans의 Java GUI 빌더를 사용하여 부분적으로 GUI를 빌드하고 있습니다. GUI 작성기를 사용하여 메뉴 항목을 관리하는 MainFrame 클래스가 있습니다. 메뉴 바 아래 MainFrame 클래스 안에있는 MainPanel 클래스가 있습니다.

그리고 나서 수동으로 다른 JPanel을 MainPanel에 추가하여 Netbeans GUI가 나를 괴롭히지 않고 GUI를 완전히 제어 할 수있게했습니다.

그러나 JButton을 JPanel에 추가하면 아무 것도 나타나지 않습니다.

(넷빈즈 코드 포함) MainFrame.java (넷빈즈 코드 포함)

package gui; 

import javax.swing.JFrame; 

/** 
* 
* @author Frank 
*/ 
public class MainFrame extends javax.swing.JFrame { 

    /** 
    * Creates new form MainFrame 
    */ 
    public MainFrame() { 
     initComponents(); 
     customInit(); 
    } 

    private void customInit() { 
     this.setTitle("Trading Card Game"); 
     this.setExtendedState(JFrame.MAXIMIZED_BOTH); 
    } 

    /** 
    * 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">//GEN-BEGIN:initComponents 
    private void initComponents() { 

     mainPanel1 = new gui.MainPanel(); 
     jMenuBar1 = new javax.swing.JMenuBar(); 
     menuFile = new javax.swing.JMenu(); 
     menuFileQuit = new javax.swing.JMenuItem(); 
     menuPreview = new javax.swing.JMenu(); 
     menuPreviewStart = new javax.swing.JMenuItem(); 

     setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); 

     javax.swing.GroupLayout mainPanel1Layout = new javax.swing.GroupLayout(mainPanel1); 
     mainPanel1.setLayout(mainPanel1Layout); 
     mainPanel1Layout.setHorizontalGroup(
      mainPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addGap(0, 400, Short.MAX_VALUE) 
     ); 
     mainPanel1Layout.setVerticalGroup(
      mainPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addGap(0, 279, Short.MAX_VALUE) 
     ); 

     menuFile.setText("File"); 

     menuFileQuit.setText("Quit"); 
     menuFileQuit.addActionListener(new java.awt.event.ActionListener() { 
      public void actionPerformed(java.awt.event.ActionEvent evt) { 
       menuFileQuitActionPerformed(evt); 
      } 
     }); 
     menuFile.add(menuFileQuit); 

     jMenuBar1.add(menuFile); 

     menuPreview.setText("Preview"); 

     menuPreviewStart.setText("Start"); 
     menuPreview.add(menuPreviewStart); 

     jMenuBar1.add(menuPreview); 

     setJMenuBar(jMenuBar1); 

     javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); 
     getContentPane().setLayout(layout); 
     layout.setHorizontalGroup(
      layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addComponent(mainPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
     ); 
     layout.setVerticalGroup(
      layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addComponent(mainPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
     ); 

     pack(); 
    }// </editor-fold>//GEN-END:initComponents 

    private void menuFileQuitActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_menuFileQuitActionPerformed 
     System.exit(0); 
    }//GEN-LAST:event_menuFileQuitActionPerformed 

    /** 
    * @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(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() { 
      @Override 
      public void run() { 
       new MainFrame().setVisible(true); 
      } 
     }); 
    } 
    // Variables declaration - do not modify//GEN-BEGIN:variables 
    private javax.swing.JMenuBar jMenuBar1; 
    private gui.MainPanel mainPanel1; 
    private javax.swing.JMenu menuFile; 
    private javax.swing.JMenuItem menuFileQuit; 
    private javax.swing.JMenu menuPreview; 
    private javax.swing.JMenuItem menuPreviewStart; 
    // End of variables declaration//GEN-END:variables 
} 

MainPanel.java :

package gui; 

import java.awt.BorderLayout; 
import java.awt.Color; 
import javax.swing.BorderFactory; 
import javax.swing.JButton; 
import model.Game; 

/** 
* 
* @author Frank 
*/ 
public class MainPanel extends javax.swing.JPanel { 

    /** 
    * Creates new form MainPanel 
    */ 
    public MainPanel() { 
     initComponents(); 
     initPanel(); 
    } 

    private void initPanel() { 
     this.setBorder(BorderFactory.createLineBorder(Color.yellow)); 
     this.add(new JButton("Test"), BorderLayout.CENTER); 
     revalidate(); 
    } 

    /** 
    * 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">//GEN-BEGIN:initComponents 
    private void initComponents() { 

     setLayout(new java.awt.BorderLayout()); 
    }// </editor-fold>//GEN-END:initComponents 
    // Variables declaration - do not modify//GEN-BEGIN:variables 
    // End of variables declaration//GEN-END:variables 
} 

황색 테두리 비록 JPanel의 주위에 도시되어있다.

"테스트"가있는 JButton이 표시되지 않는 이유는 무엇입니까? 상황 설명

이미지 (아무 버튼을 보지를!) : no button http://img4.imageshack.us/img4/1466/so1l.jpg

감사합니다.

Answer 1

mainPanel1의 레이아웃을 덮어 쓰고 있기 때문입니다.

이 줄들은 MainFrame.java에 주석 처리되었으며 테스트 단추는 예상대로 나타났습니다.

//  javax.swing.GroupLayout mainPanel1Layout = new javax.swing.GroupLayout(mainPanel1); 
//  mainPanel1.setLayout(mainPanel1Layout); 
//  mainPanel1Layout.setHorizontalGroup(
//   mainPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
//   .addGap(0, 400, Short.MAX_VALUE) 
//  ); 
//  mainPanel1Layout.setVerticalGroup(
//   mainPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
//   .addGap(0, 279, Short.MAX_VALUE) 
//  );