Java Swing: JDialog, JPanel & JToggleButton

Java JDialog

The JDialog control represents a top level window with a border and a title used to take some form of input from the user. It inherits the Dialog class.

Unlike JFrame, it doesn't have maximize and minimize buttons.

JDialog class declaration

Let's see the declaration for javax.swing.JDialog class.

1. public class JDialog extends Dialog implements WindowConstants, Accessible, RootPaneContainer  

Commonly used Constructors:

Constructor	Description
JDialog()	It is used to create a modeless dialog without a title and without a specified Frame owner.
JDialog(Frame owner)	It is used to create a modeless dialog with specified Frame as its owner and an empty title.
JDialog(Frame owner, String title, boolean modal)	It is used to create a dialog with the specified title, owner Frame and modality.

Java JDialog Example

1. import javax.swing.*;  
2. import java.awt.*;  
3. import java.awt.event.*;  
4. public class DialogExample {  
5.     private static JDialog d;  
6.     DialogExample() {  
7.         JFrame f= new JFrame();  
8.         d = new JDialog(f , "Dialog Example", true);  
9.         d.setLayout( new FlowLayout() );  
10.         JButton b = new JButton ("OK");  
11.         b.addActionListener ( new ActionListener()  
12.         {  
13.             public void actionPerformed( ActionEvent e )  
14.             {  
15.                 DialogExample.d.setVisible(false);  
16.             }  
17.         });  
18.         d.add( new JLabel ("Click button to continue."));  
19.         d.add(b);   
20.         d.setSize(300,300);    
21.         d.setVisible(true);  
22.     }  
23.     public static void main(String args[])  
24.     {  
25.         new DialogExample();  
26.     }  
27. }  

Output:

Java JPanel

The JPanel is a simplest container class. It provides space in which an application can attach any other component. It inherits the JComponents class.

It doesn't have title bar.

JPanel class declaration

1. public class JPanel extends JComponent implements Accessible  

Commonly used Constructors:

Constructor	Description
JPanel()	It is used to create a new JPanel with a double buffer and a flow layout.
JPanel(boolean isDoubleBuffered)	It is used to create a new JPanel with FlowLayout and the specified buffering strategy.
JPanel(LayoutManager layout)	It is used to create a new JPanel with the specified layout manager.

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Java JPanel Example

1. import java.awt.*;  
2. import javax.swing.*;  
3. public class PanelExample {  
4.      PanelExample()  
5.         {  
6.         JFrame f= new JFrame("Panel Example");    
7.         JPanel panel=new JPanel();  
8.         panel.setBounds(40,80,200,200);    
9.         panel.setBackground(Color.gray);  
10.         JButton b1=new JButton("Button 1");     
11.         b1.setBounds(50,100,80,30);    
12.         b1.setBackground(Color.yellow);   
13.         JButton b2=new JButton("Button 2");   
14.         b2.setBounds(100,100,80,30);    
15.         b2.setBackground(Color.green);   
16.         panel.add(b1); panel.add(b2);  
17.         f.add(panel);  
18.                 f.setSize(400,400);    
19.                 f.setLayout(null);    
20.                 f.setVisible(true);    
21.         }  
22.         public static void main(String args[])  
23.         {  
24.         new PanelExample();  
25.         }  
26.     }  

Output:

Java JFileChooser

The object of JFileChooser class represents a dialog window from which the user can select file. It inherits JComponent class.

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JFileChooser class declaration

Let's see the declaration for javax.swing.JFileChooser class.

1. public class JFileChooser extends JComponent implements Accessible  

Commonly used Constructors:

Constructor	Description
JFileChooser()	Constructs a JFileChooser pointing to the user's default directory.
JFileChooser(File currentDirectory)	Constructs a JFileChooser using the given File as the path.
JFileChooser(String currentDirectoryPath)	Constructs a JFileChooser using the given path.

Java JFileChooser Example

1. import javax.swing.*;    
2. import java.awt.event.*;    
3. import java.io.*;    
4. public class FileChooserExample extends JFrame implements ActionListener{    
5. JMenuBar mb;    
6. JMenu file;    
7. JMenuItem open;    
8. JTextArea ta;    
9. FileChooserExample(){    
10. open=new JMenuItem("Open File");    
11. open.addActionListener(this);            
12. file=new JMenu("File");    
13. file.add(open);             
14. mb=new JMenuBar();    
15. mb.setBounds(0,0,800,20);    
16. mb.add(file);              
17. ta=new JTextArea(800,800);    
18. ta.setBounds(0,20,800,800);              
19. add(mb);    
20. add(ta);              
21. }    
22. public void actionPerformed(ActionEvent e) {    
23. if(e.getSource()==open){    
24.     JFileChooser fc=new JFileChooser();    
25.     int i=fc.showOpenDialog(this);    
26.     if(i==JFileChooser.APPROVE_OPTION){    
27.         File f=fc.getSelectedFile();    
28.         String filepath=f.getPath();    
29.         try{  
30.         BufferedReader br=new BufferedReader(new FileReader(filepath));    
31.         String s1="",s2="";                         
32.         while((s1=br.readLine())!=null){    
33.         s2+=s1+"\n";    
34.         }    
35.         ta.setText(s2);    
36.         br.close();    
37.         }catch (Exception ex) {ex.printStackTrace();  }                 
38.     }    
39. }    
40. }          
41. public static void main(String[] args) {    
42.     FileChooserExample om=new FileChooserExample();    
43.              om.setSize(500,500);    
44.              om.setLayout(null);    
45.              om.setVisible(true);    
46.              om.setDefaultCloseOperation(EXIT_ON_CLOSE);    
47. }    
48. }  

Output:

  

Java JToggleButton

JToggleButton is used to create toggle button, it is two-states button to switch on or off.

Nested Classes

Modifier and Type	Class	Description
protected class	JToggleButton.AccessibleJToggleButton	This class implements accessibility support for the JToggleButton class.
static class	JToggleButton.ToggleButtonModel	The ToggleButton model

Constructors

Constructor	Description
JToggleButton()	It creates an initially unselected toggle button without setting the text or image.
JToggleButton(Action a)	It creates a toggle button where properties are taken from the Action supplied.
JToggleButton(Icon icon)	It creates an initially unselected toggle button with the specified image but no text.
JToggleButton(Icon icon, boolean selected)	It creates a toggle button with the specified image and selection state, but no text.
JToggleButton(String text)	It creates an unselected toggle button with the specified text.
JToggleButton(String text, boolean selected)	It creates a toggle button with the specified text and selection state.
JToggleButton(String text, Icon icon)	It creates a toggle button that has the specified text and image, and that is initially unselected.
JToggleButton(String text, Icon icon, boolean selected)	It creates a toggle button with the specified text, image, and selection state.

Methods

Modifier and Type	Method	Description
AccessibleContext	getAccessibleContext()	It gets the AccessibleContext associated with this JToggleButton.
String	getUIClassID()	It returns a string that specifies the name of the l&f class that renders this component.
protected String	paramString()	It returns a string representation of this JToggleButton.
void	updateUI()	It resets the UI property to a value from the current look and feel.

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JToggleButton Example

1. import java.awt.FlowLayout;  
2. import java.awt.event.ItemEvent;  
3. import java.awt.event.ItemListener;  
4. import javax.swing.JFrame;  
5. import javax.swing.JToggleButton;  
6.   
7. public class JToggleButtonExample extends JFrame implements ItemListener {  
8.     public static void main(String[] args) {  
9.         new JToggleButtonExample();  
10.     }  
11.     private JToggleButton button;  
12.     JToggleButtonExample() {  
13.         setTitle("JToggleButton with ItemListener Example");  
14.         setLayout(new FlowLayout());  
15.         setJToggleButton();  
16.         setAction();  
17.         setSize(200, 200);  
18.         setVisible(true);  
19.         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
20.     }  
21.     private void setJToggleButton() {  
22.         button = new JToggleButton("ON");  
23.         add(button);  
24.     }  
25.     private void setAction() {  
26.         button.addItemListener(this);  
27.     }  
28.     public void itemStateChanged(ItemEvent eve) {  
29.         if (button.isSelected())  
30.             button.setText("OFF");  
31.         else  
32.             button.setText("ON");  
33.     }  
34. }  

Output

Anurag Rana Educator CSE/IT