JRadioButtons in Java Swing

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In AWT, radio buttons are check boxes that belongs to the same CheckboxGroup, which ensures that only one check box is selected at a time.

Radio buttons are implemented in Swing through the JRadioButton class. The constructor methods are the same as those for the JCheckBox class.

Example:

The following example creates two radio buttons one with a text and the other with a text and an icon displayed on it.

JRadioButon rd,imgIcon; ImageIcon imgIcon=new ImageIcon("Img0001.gif"); rd=new JRadioButton("Radio One"); imgIcon=new JRadioButton("Radio Two",imgIcon);

The following table describes some of the methods provided by the JRadioButton class

Methods	Description
String getLabel() void setLabel(String)	Sets or gets a label for a radio box
boolean getState() void setState(Boolean)	Set or gets the status of the radio box

Example:

The following example creates four radio buttons, of which one pair will have an icon. The others will have the traditional radio button shown. By default the first and the last radio butons are checked, while the others are not checked. The example uses a method called 'setSelectedIcon()' which is used to replace the previous gif with the gif passed as a parameter to the method. This is done to show that the radio button is selected.

For example in the following code, radio button rbIconLeft displays an icon 'Back_up.gif'. This icon represents a back arrow. When this radio button is selected, the method setSelectedIcon() is used which sets 'Back_up.gif' to 'Back_sel.gif' to specify that the radio button is selected.

/* =========================================================== File Name : JRadioButtonsDemo.java WebSite : http://javaproglang.blogspot.in/ Facebook : https://www.facebook.com/AdvanceJavaProgramming Twitter ID : https://twitter.com/AdvanceJava Created By : Bintu Chaudhary =========================================================== */ import javax.swing.*; import java.awt.event.*; public class JRadioButtonsDemo extends JPanel { JRadioButton rbtLeft, rbtRight, rbtIconLeft, rbtIconRight; ButtonGroup btngrpUp, btngrpDown; Icon imgIconBkUp, imgIconBkSel; Icon imgIconFdUp, imgIconFdSel; public JRadioButtonsDemo() { imgIconBkUp = new ImageIcon("Images/Back_up.gif"); imgIconBkSel = new ImageIcon("Images/Back_sel.gif"); imgIconFdUp = new ImageIcon("Images/Forw_up.gif"); imgIconFdSel = new ImageIcon("Images/Forw_sel.gif"); btngrpUp = new ButtonGroup(); btngrpDown = new ButtonGroup(); rbtLeft = new JRadioButton("Radio Left", true); rbtRight = new JRadioButton("Radio Right", false); rbtIconLeft = new JRadioButton("Radio Left", imgIconBkUp, false); /* setSelectedIcon() method specifies the image displayed, when the object is selected */ rbtIconLeft.setSelectedIcon(imgIconBkSel); rbtIconRight = new JRadioButton("Radio Right", imgIconFdUp, true); /* setSelectedIcon() method specifies the image displayed, when the object is selected */ rbtIconRight.setSelectedIcon(imgIconFdSel); btngrpUp.add(rbtLeft); btngrpUp.add(rbtRight); btngrpDown.add(rbtIconLeft); btngrpDown.add(rbtIconRight); // Add Radio Button to the Panel. add(rbtLeft); add(rbtRight); add(rbtIconLeft); add(rbtIconRight); } public static void main(String[] args) { JRadioButtonsDemo myRd = new JRadioButtonsDemo(); // Calls the MyCheckBox constructor. JFrame frm = new JFrame("Radio Button Demo"); // Set the text on the frame frm.setContentPane(myRd); frm.setSize(250,200); // setSize() method is used to specify the width and height of the frame frm.setVisible(true); // To display the Frame WindowListener listener = new WindowAdapter() { public void windowClosing(WindowEvent winEvt) { System.exit(0); } }; // End of WindowAdaptor() method frm.addWindowListener(listener); // Window listener activates the windowClosing() method } }

C:\>jdk1.4\bin>javac JRadioButtonsDemo.java
C:\>jdk1.4\bin>java JRadioButtonsDemo

"Output of JRadioButtonsDemo.class"

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Java Swing-1

JFrame	JPanel	JApplet
JButtons	JLabels	JTextFields
JPasswordField	JTextAreas	JCheckBoxes
JRadioButtons	JList	JComboBox