Question

What is the solution for chapter 15 3e for java programming 8th edition

Create a JFrame that holds fjive buttons with the names of five different fonts. Include a sexth button that the user can click to make a font larger or smaller. Display a demonstration JLabel usig the font and size that th user selects.

Answer 1

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

import java.util.Random;

import java.util.HashSet;

public class JFontFrame extends JFrame implements ActionListener

{

private final String demoText = "The font you selected looks like this.";

private JLabel demonstration = new JLabel("Please select choose a font", JLabel.CENTER);

private JButton[] fontButtons = new JButton[4];

GridLayout mainLayout = new GridLayout(2, 0);

Container buttonArea = new Container();

public JFontFrame()

{

super("JFontFrame");

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setSize(350, 300);

setResizable(false);

setLocationRelativeTo(null);

setLayout(mainLayout);

buttonArea.setLayout(new FlowLayout());

addWindowComponents();

add(demonstration);

add(buttonArea);

}

private void addWindowComponents()

{

String[] fonts = chooseFonts();

for(int i = 0; i < fontButtons.length; i++)

{

fontButtons[i] = new JButton(fonts[i]);

buttonArea.add(fontButtons[i]);

fontButtons[i].addActionListener(this);

}

}

private String[] chooseFonts()

{

Random random = new Random();

GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();

Font[] fonts = ge.getAllFonts();

HashSet<Integer> set = new HashSet<Integer>(); // Thanks to google

int i = 0;

String[] fontList = new String[4];

while(i < 4)

{

int rand = random.nextInt(fonts.length);

if(!(set.contains(rand)))

{

set.add(rand);

fontList[i] = fonts[rand].getFontName();

}

i++;

}

return fontList;

}

public void actionPerformed(ActionEvent e)

{

JButton source = (JButton)e.getSource();

String choice = source.getText();

changeDemonstration(choice);

}

private void changeDemonstration(String f)

{

try

{

demonstration.setText(demoText);

Font newFont = new Font(f, Font.PLAIN, 12);

demonstration.setFont(newFont);

}

catch(Exception e)

{

JOptionPane.showMessageDialog(null, "Error setting font!\n" + e);

System.exit(1);

}

}

public static void main(String[] args)

{

JFontFrame fontWindow = new JFontFrame();

fontWindow.setVisible(true);

}

}