JScrollPanes.java Source code

Introduction

Here is the source code for JScrollPanes.java

Source

// : c14:JScrollPanes.java
// Controlling the scrollbars in a JScrollPane.
// <applet code=JScrollPanes width=300 height=725></applet>
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.

import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BorderFactory;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.border.Border;

public class JScrollPanes extends JApplet {
    private JButton b1 = new JButton("Text Area 1"), b2 = new JButton("Text Area 2"),
            b3 = new JButton("Replace Text"), b4 = new JButton("Insert Text");

    private JTextArea t1 = new JTextArea("t1", 1, 20), t2 = new JTextArea("t2", 4, 20),
            t3 = new JTextArea("t3", 1, 20), t4 = new JTextArea("t4", 10, 10), t5 = new JTextArea("t5", 4, 20),
            t6 = new JTextArea("t6", 10, 10);

    private JScrollPane sp3 = new JScrollPane(t3, JScrollPane.VERTICAL_SCROLLBAR_NEVER,
            JScrollPane.HORIZONTAL_SCROLLBAR_NEVER),
            sp4 = new JScrollPane(t4, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                    JScrollPane.HORIZONTAL_SCROLLBAR_NEVER),
            sp5 = new JScrollPane(t5, JScrollPane.VERTICAL_SCROLLBAR_NEVER,
                    JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS),
            sp6 = new JScrollPane(t6, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                    JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);

    class B1L implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            t5.append(t1.getText() + "\n");
        }
    }

    class B2L implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            t2.setText("Inserted by Button 2");
            t2.append(": " + t1.getText());
            t5.append(t2.getText() + "\n");
        }
    }

    class B3L implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            String s = " Replacement ";
            t2.replaceRange(s, 3, 3 + s.length());
        }
    }

    class B4L implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            t2.insert(" Inserted ", 10);
        }
    }

    public void init() {
        Container cp = getContentPane();
        cp.setLayout(new FlowLayout());
        // Create Borders for components:
        Border brd = BorderFactory.createMatteBorder(1, 1, 1, 1, Color.BLACK);
        t1.setBorder(brd);
        t2.setBorder(brd);
        sp3.setBorder(brd);
        sp4.setBorder(brd);
        sp5.setBorder(brd);
        sp6.setBorder(brd);
        // Initialize listeners and add components:
        b1.addActionListener(new B1L());
        cp.add(b1);
        cp.add(t1);
        b2.addActionListener(new B2L());
        cp.add(b2);
        cp.add(t2);
        b3.addActionListener(new B3L());
        cp.add(b3);
        b4.addActionListener(new B4L());
        cp.add(b4);
        cp.add(sp3);
        cp.add(sp4);
        cp.add(sp5);
        cp.add(sp6);
    }

    public static void main(String[] args) {
        run(new JScrollPanes(), 300, 725);
    }

    public static void run(JApplet applet, int width, int height) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(applet);
        frame.setSize(width, height);
        applet.init();
        applet.start();
        frame.setVisible(true);
    }
} ///:~