JTextComponent 3

JTextComponent 3

• ドキュメントの変更を感知
• キャレットの状態を感知

import java.awt.BorderLayout;
import java.awt.Rectangle;
 
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
 
/**
 * @see http://java.sun.com/docs/books/tutorial/uiswing/components/generaltext.html
 */
public class JTextTest3 {
    private JFrame frame;
    private JTextArea txtArea;
    private JLabel changeStats;
    private CaretListenerLabel caretStats;
    
    private void createUI() {
        frame = new JFrame("TextTest3");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        caretStats  = new CaretListenerLabel("caret:");
        changeStats = new JLabel("change:");
        JPanel statusPanel = new JPanel(new BorderLayout());
        statusPanel.add(changeStats, BorderLayout.CENTER);
        statusPanel.add(caretStats, BorderLayout.SOUTH);
        
        txtArea = new JTextArea(10, 30);
 
        JPanel basePanel = new JPanel(new BorderLayout());
        basePanel.add(new JScrollPane(txtArea), BorderLayout.CENTER);
        basePanel.add(statusPanel, BorderLayout.SOUTH);
        
        txtArea.getDocument().addDocumentListener(
                new MyDocumentListener());
        txtArea.addCaretListener(caretStats);
        
        frame.getContentPane().add(basePanel);
        frame.pack();
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(
                new Runnable(){
                    public void run() {
                        JTextTest3 jft = new JTextTest3();
                        jft.createUI();
                    }
                }
        );
    }
    /**
     * ドキュメントの変更を感知
     */
    class MyDocumentListener implements DocumentListener {
        public void changedUpdate(DocumentEvent e) {
            changeStats.setText("chage:chage");
        }
        public void insertUpdate(DocumentEvent e) {
            changeStats.setText("change:insert");   
        }
        public void removeUpdate(DocumentEvent e) {
            changeStats.setText("change:remove");
        }
    }
    /**
     * キャレットの状態を感知
     */
    @SuppressWarnings("serial")
    class CaretListenerLabel extends JLabel
                                implements CaretListener {
        public CaretListenerLabel(String label) {
            super(label);
        }
        public void caretUpdate(CaretEvent e) {
            try {
                int dot = e.getDot();
                // モデル内の指定された位置を、ビュー座標系内の場所に変換
                Rectangle rect = txtArea.modelToView(dot);
                caretStats.setText("caret: text pos=" + dot 
                              + " view location [" + rect.x + "," + rect.y + "]");
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }
    }
}