java将JPanel添加到JFrame
我正试图将这个JPanel添加到JFrame中,但我看不到他。 当我创建新的java类并自己制作这个框架时,一切都很好
来自JFrame表单的代码
public class MainFrame extends javax.swing.JFrame
{
/**
* Creates new form MainFrame
*/
public MainFrame()
{
this.getContentPane().add(firstPanel);
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()
{
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 400, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 300, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
/**
* @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()
{
public void run()
{
new MainFrame().setVisible(true);
}
});
}
// Variables declaration - do not modify
// End of variables declaration
FirstPanel firstPanel = new FirstPanel();
}
来自JPanel的代码:
public class FirstPanel extends javax.swing.JPanel
{
/**
* Creates new form FirstPanel
*/
public FirstPanel()
{
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();
setBackground(new java.awt.Color(0, 0, 0));
jButton1.setText("jButton1");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
this.setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(164, Short.MAX_VALUE)
.addComponent(jButton1)
.addGap(155, 155, 155))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(129, 129, 129)
.addComponent(jButton1)
.addContainerGap(145, Short.MAX_VALUE))
);
}// </editor-fold>
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
// End of variables declaration
}
来自Java类的代码
public class mainn extends JFrame
{
public mainn()
{ this.setSize(700,600);
this.getContentPane().add(firstPanel);
}
FirstPanel firstPanel = new FirstPanel();
public static void main(String args[])
{
java.awt.EventQueue.invokeLater(new Runnable()
{
@Override
public void run()
{
new mainn().setVisible(true);
}
});
}
}
我想不出有什么区别。谁能帮帮我吗
# 1 楼答案
您还必须在JPanel上调用setVisible(true)