Introductie tot JButton in Java
De klasse JButton in Java wordt gebruikt om drukknoppen te maken die kunnen worden gebruikt om elke ActionEvent uit te voeren wanneer erop wordt geklikt. Om gebeurtenisactie te bereiken, moet de ActionListener-interface worden geïmplementeerd. Het onderdeel Knoppen in Swing is vergelijkbaar met dat van het onderdeel AWT-knop, behalve dat het tekst, afbeelding of beide kan bevatten. De JButton-klasse breidt de JComponent-klasse uit en kan in een container worden gebruikt.
JButton Class-verklaring
De klasse Declaratie van javax.swing.JButton staat hieronder:
public class JButton extends AbstractButton implements Accessible
Soorten constructeurs gebruikt in JButton Class
Er zijn vijf soorten constructors die voornamelijk worden gebruikt in JButton Class:
1. JButton ()
Deze constructor maakt een knop in het onderdeel zonder pictogram of tekst.
Voorbeeld
import java.awt.*;
import javax.swing.*;
public class JButtonExample (
public static void main(String() args) (
JFrame frame=new JFrame("Button Example");
JButton b=new JButton();
b.setPreferredSize(new Dimension(100, 30));
frame.add(b);
frame.setSize(500, 500);
frame.setLayout(new FlowLayout());
frame.setVisible(true);
)
)
Output:
2. JButton (String-tekst)
Deze constructor maakt een knop in de component met de opgegeven tekst in de parameters.
Voorbeeld
import java.awt.*;
import javax.swing.*;
public class JButtonExample (
public static void main(String() args) (
JFrame frame=new JFrame("Button Example");
JButton b=new JButton("Click Here");
b.setPreferredSize(new Dimension(100, 30));
frame.add(b);
frame.setSize(500, 500);
frame.setLayout(new FlowLayout());
frame.setVisible(true);
)
)
Output:
3. JButton (pictogram afbeelding)
Deze constructor maakt een knop in de component met de afbeelding img in de parameters.
Voorbeeld
import java.awt.*;
import javax.swing.*;
public class JButtonExample (
public static void main(String() args) (
JFrame frame=new JFrame("Button Example");
JButton b=new JButton(new ImageIcon("C:\\custom.png.webp"));
frame.add(b);
frame.setSize(500, 500);
frame.setLayout(new FlowLayout());
frame.setVisible(true);
)
)
Output:
4. JButton (actie a)
Deze constructor maakt een knop in de component met de eigenschappen die worden geleverd door de actie an in de parameter.
Voorbeeld
importawt.*;
import java.awt.event.ActionEvent;
import javax.swing.*;
public class JButtonExample extends JFrame(
private JButton reg;
private Action action = new buttonAction();
public JButtonExample() (
super("JButton Demo example");
setLayout(new FlowLayout());
reg = new JButton(action);
reg.setPreferredSize(new Dimension(100, 30));
add(reg);
)
public class buttonAction extends AbstractAction(
public void actionPerformed(ActionEvent e)
(
JOptionPane.showMessageDialog(null, "Button click");
)
)
public static void main(String() args) (
JButtonExample jb = new JButtonExample();
jb.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jb.setSize(300, 300);
jb.setVisible(true);
)
)
Output:
5. JButton (String-tekst, Icon img)
Deze constructor maakt een knop in de component met de tekst en de opgegeven afbeelding in de parameters.
Voorbeeld
import java.awt.*;
import javax.swing.*;
public class JButtonExample (
public static void main(String() args) (
JFrame frame=new JFrame("Button Example");
JButton b=new JButton("Click here", new ImageIcon("C:\\custom.png.webp"));
frame.add(b);
frame.setSize(500, 500);
frame.setLayout(new FlowLayout());
frame.setVisible(true);
)
)
Output:
Methoden van JButton Class
Hieronder staan de meest gebruikte methoden in JButton Class:
- Void setText (string-tekst): deze methode wordt in principe gebruikt om specifieke tekst op de knop in de component in te stellen.
- String getText (): deze methode wordt gebruikt om de tekst van de knop in het opgegeven onderdeel te retourneren.
- Void setEnabled (boolean b): deze methode wordt gebruikt om een knop in of uit te schakelen door de juiste waarde in de parameter door te geven.
- Void setIcon (pictogram i): deze methode wordt gebruikt om het opgegeven pictogram "I" op de knop in te stellen.
- Pictogram getIcon (): deze methode wordt gebruikt om het pictogram van de opgegeven knop terug te geven.
- Void setHorizontalTextPosition (int hpos): deze methode wordt gebruikt om de horizontale positie van het knopbericht ten opzichte van het pictogram in te stellen.
- Void stVerticalTextPosition (int vpos): deze methode wordt gebruikt om de verticale positie van het knopbericht ten opzichte van het pictogram in te stellen.
Voorbeeld van JButton Class
Hieronder is het voorbeeld van de JButton-klasse:
CRUD-bewerking op JTable
package jbuttonapplication;
import javax.swing.table.DefaultTableModel;
public class NewJFrame extends javax.swing.JFrame (
public NewJFrame() (
initComponents();
)
private void initComponents() (
jPanel1 = new javax.swing.JPanel();
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
rno = new javax.swing.JTextField();
fname = new javax.swing.JTextField();
lname = new javax.swing.JTextField();
add = new javax.swing.JTextField();
jScrollPane1 = new javax.swing.JScrollPane();
jbtable = new javax.swing.JTable();
jbnew = new javax.swing.JButton();
jbadd = new javax.swing.JButton();
jbupdate = new javax.swing.JButton();
jbdelete = new javax.swing.JButton();
label = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel1.setText("Roll No");
jLabel2.setText("First Name");
jLabel3.setText("Last Name");
jLabel4.setText("Address");
jbtable.setModel(new javax.swing.table.DefaultTableModel(
new Object ()() (
),
new String () (
"Roll No", "First Name", "Last Name", "Address"
)
) (
Class() types = new Class () (
java.lang.Integer.class, java.lang.String.class, java.lang.String.class, java.lang.String.class
);
public Class getColumnClass(int columnIndex) (
return types (columnIndex);
)
));
jbtable.addMouseListener(new java.awt.event.MouseAdapter() (
public void mouseClicked(java.awt.event.MouseEvent evt) (
jbtableMouseClicked(evt);
)
));
jScrollPane1.setViewportView(jbtable);
jbnew.setText("New");
jbnew.addActionListener(new java.awt.event.ActionListener() (
public void actionPerformed(java.awt.event.ActionEvent evt) (
jbnewActionPerformed(evt);
)
));
jbadd.setText("Add");
jbadd.addActionListener(new java.awt.event.ActionListener() (
public void actionPerformed(java.awt.event.ActionEvent evt) (
jbaddActionPerformed(evt);
)
));
jbupdate.setText("Update");
jbupdate.addActionListener(new java.awt.event.ActionListener() (
public void actionPerformed(java.awt.event.ActionEvent evt) (
jbupdateActionPerformed(evt);
)
));
jbdelete.setText("Delete");
jbdelete.addActionListener(new java.awt.event.ActionListener() (
public void actionPerformed(java.awt.event.ActionEvent evt) (
jbdeleteActionPerformed(evt);
)
));
label.setForeground(new java.awt.Color(204, 0, 0));
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(136, 136, 136)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel1)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jLabel2)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel4)
.addComponent(jLabel3)
.addComponent(jbnew))))
.addGap(37, 37, 37)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(rno, javax.swing.GroupLayout.DEFAULT_SIZE, 200, Short.MAX_VALUE)
.addComponent(fname)
.addComponent(lname)
.addComponent(add))
.addGap(32, 32, 32)
.addComponent(label, javax.swing.GroupLayout.PREFERRED_SIZE, 375, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(jPanel1Layout.createSequentialGroup()
.addComponent(jbadd)
.addGap(46, 46, 46)
.addComponent(jbupdate)
.addGap(74, 74, 74)
.addComponent(jbdelete))))
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(2, 2, 2)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addContainerGap(177, Short.MAX_VALUE))
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(117, 117, 117)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(rno, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(label))
.addComponent(jLabel1))
.addGap(18, 18, 18)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(fname, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel2))
.addGap(18, 18, 18)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel3)
.addComponent(lname, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel4)
.addComponent(add, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(46, 46, 46)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jbnew)
.addComponent(jbadd)
.addComponent(jbupdate)
.addComponent(jbdelete))
.addGap(52, 52, 52)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 130, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(328, Short.MAX_VALUE))
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
pack();
)
private void jbnewActionPerformed(java.awt.event.ActionEvent evt) (
rno.setText("");
fname.setText("");
lname.setText("");
add.setText("");
)
private void jbaddActionPerformed(java.awt.event.ActionEvent evt) (
label.setText("");
DefaultTableModel model = (DefaultTableModel)jbtable.getModel();
if(!rno.getText().isEmpty()&&!fname.getText().isEmpty()
&&!lname.getText().isEmpty()&&!add.getText().isEmpty())
(
model.addRow(new Object()(rno.getText().trim(), fname.getText().trim(),
lname.getText().trim(), add.getText().trim()));
)
else
(
label.setText("All the fields should be filled");
)
)
private void jbtableMouseClicked(java.awt.event.MouseEvent evt) (
DefaultTableModel model = (DefaultTableModel)jbtable.getModel();
rno.setText(model.getValueAt(jbtable.getSelectedRow(), 0).toString());
fname.setText(model.getValueAt(jbtable.getSelectedRow(), 1).toString());
lname.setText(model.getValueAt(jbtable.getSelectedRow(), 2).toString());
add.setText(model.getValueAt(jbtable.getSelectedRow(), 3).toString());
)
private void jbupdateActionPerformed(java.awt.event.ActionEvent evt) (
label.setText("");
DefaultTableModel model = (DefaultTableModel)jbtable.getModel();
if(jbtable.getSelectedRow()==-1)
(
if(jbtable.getRowCount()==0)
(
label.setText("Table is Empty");
)
else
(
label.setText("No Row Selected to Update");
)
)
else
(
model.setValueAt(rno.getText(), jbtable.getSelectedRow(), 0);
model.setValueAt(fname.getText(), jbtable.getSelectedRow(), 1);
model.setValueAt(lname.getText(), jbtable.getSelectedRow(), 2);
model.setValueAt(add.getText(), jbtable.getSelectedRow(), 3);
)
)
private void jbdeleteActionPerformed(java.awt.event.ActionEvent evt) (
label.setText("");
DefaultTableModel model = (DefaultTableModel)jbtable.getModel();
if(jbtable.getSelectedRow()==-1)
(
if(jbtable.getRowCount()==0)
(
label.setText("Table is Empty");
)
else
(
label.setText("No Row Selected to Update");
)
)
else
(
model.removeRow(jbtable.getSelectedRow());
)
)
public static void main(String args()) (
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(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
) catch (InstantiationException ex) (
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
) catch (IllegalAccessException ex) (
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
) catch (javax.swing.UnsupportedLookAndFeelException ex) (
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
)
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() (
public void run() (
new NewJFrame().setVisible(true);
)
));
)
// Variables declaration - do not modify
private javax.swing.JTextField add;
private javax.swing.JTextField fname;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JPanel jPanel1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JButton jbadd;
private javax.swing.JButton jbdelete;
private javax.swing.JButton jbnew;
private javax.swing.JTable jbtable;
private javax.swing.JButton jbupdate;
private javax.swing.JLabel label;
private javax.swing.JTextField lname;
private javax.swing.JTextField rno;
// End of variables declaration
)
Output:
Conclusies - JButton in Java
De klasse JButton kan worden gebruikt om een knopcomponent te maken om de wijzigingen in de component op een dynamische manier uit te voeren, zoals in het bovenstaande voorbeeld.
Aanbevolen artikelen
Dit is een handleiding voor JButton in Java. Hier bespreken we de soorten constructors die in JButton Class worden gebruikt, samen met methoden en voorbeelden. U kunt ook onze andere voorgestelde artikelen doornemen voor meer informatie -
- JTextField in Java
- JDialog in Java
- BorderLayout in Java
- CardLayout in Java
- JPanel in Java (Constructors)
- GroupLayout in Java
- Voorbeelden van JFrame in Java
- JLabel in Java
- Volledige gids voor Flowlayout in Java
- Methoden en programma JTable in Java