GUI Components: Part 1 - Java: How to Program Early Objects - page 502

1 // Fig. 12.19: RadioButtonFrame.java

2 // Creating radio buttons using ButtonGroup and JRadioButton.

3 import java.awt.FlowLayout;

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import java.awt.Font;

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import java.awt.event.ItemListener;

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import java.awt.event.ItemEvent;

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import javax.swing.JFrame;

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import javax.swing.JTextField;

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import javax.swing.JRadioButton;

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import javax.swing.ButtonGroup;

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public class RadioButtonFrame extends JFrame

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{

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private final JTextField textField; // used to display font changes

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private final Font plainFont; // font for plain text

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private final Font boldFont; // font for bold text

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private final Font italicFont; // font for italic text

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private final Font boldItalicFont; // font for bold and italic text

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private final JRadioButton plainJRadioButton; // selects plain text
private final JRadioButton boldJRadioButton; // selects bold text
private final JRadioButton italicJRadioButton; // selects italic text
private final JRadioButton boldItalicJRadioButton; // bold and italic
private final ButtonGroup radioGroup; // holds radio buttons

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// RadioButtonFrame constructor adds JRadioButtons to JFrame

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public RadioButtonFrame()

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{

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super ( "RadioButton Test" );

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setLayout( new FlowLayout());

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textField = new JTextField( "Watch the font style change" , 25 );

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add(textField); // add textField to JFrame

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// create radio buttons

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plainJRadioButton = new JRadioButton( "Plain" , true );
boldJRadioButton = new JRadioButton( "Bold" , false );
italicJRadioButton = new JRadioButton( "Italic" , false );
boldItalicJRadioButton = new JRadioButton( "Bold/Italic" , false );

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add(plainJRadioButton); // add plain button to JFrame

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add(boldJRadioButton); // add bold button to JFrame

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add(italicJRadioButton); // add italic button to JFrame

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add(boldItalicJRadioButton); // add bold and italic button

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44 // create logical relationship between JRadioButtons

radioGroup = new ButtonGroup(); // create ButtonGroup
radioGroup.add(plainJRadioButton); // add plain to group
radioGroup.add(boldJRadioButton); // add bold to group
radioGroup.add(italicJRadioButton); // add italic to group
radioGroup.add(boldItalicJRadioButton); // add bold and italic

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51 // create font objects

52 plainFont = new Font( "Serif" , Font.PLAIN , 14 );

53 boldFont = new Font( "Serif" , Font.BOLD , 14 );

Fig. 12.19 | Creating radio buttons using ButtonGroup and JRadioButton . (Part 1 of 2.)