bookmarkcontroller.java~

书籍"Java_面向事件编程"的附带光盘代码

import objectdraw.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

// allows the user to type urls into a text field.  Matching urls are displayed
// below.
public class BookmarkController extends JFrame implements ActionListener{
    
    // Dimensions of the window
    private static final int WINDOW_WIDTH = 500;
    private static final int WINDOW_HEIGHT = 200;
    
    // size of TextField
    private static final int COLS = 30;

    private JTextField descField;     // link description
    private JTextField addrField;     // target address
    private JButton enter;            // enter a new bookmark
    private JButton save;             // save the list of bookmarks
    private JButton load;             // load a list of bookmarks

    private BookmarkList theList;     // the list of bookmarks

    public void begin() {
        Container contentPane = getContentPane();
        
        // prepare description field & label
        JPanel descPanel = new JPanel();
        JLabel descLabel = new JLabel("Description:");
        descField = new JTextField(COLS);
        
        descPanel.add(descLabel);
        descPanel.add(descField);
        contentPane.add(descPanel, BorderLayout.NORTH);

        // prepare address field & label
        JPanel addrPanel = new JPanel();
        JLabel addrLabel = new JLabel("Address:");
        addrField = new JTextField(COLS);
        
        addrPanel.add(addrLabel);
        addrPanel.add(addrField);
        contentPane.add(addrPanel, BorderLayout.CENTER);
    
        // prepare the buttons
        JPanel buttonPanel = new JPanel();
        enter = new JButton("Enter");
        enter.addActionListener(this);
        save = new JButton("Save List");
        save.addActionListener(this);
        load = new JButton("Load List");
        load.addActionListener(this);

        buttonPanel.add(enter);
        buttonPanel.add(save);
        buttonPanel.add(load);
        contentPane.add(buttonPanel, BorderLayout.SOUTH);

        validate();
        
        theList = new BookmarkList();
    }
    
    // add a bookmark, save the list, or load a new one according to
    // the button pressed
    public void actionPerformed(ActionEvent evt) {
        if ( evt.getSource() == enter ){
            theList.add( new Bookmark(descField.getText(), addrField.getText()) );
        }
        else if (evt.getSource() == save) {
            theList.saveBookmarksFile();
        }
        else {
            theList.retrieveBookmarksFile();
        }
        descField.setText("");
        addrField.setText("");
    }
    
    public static void main( String[] args ) {
        BookmarkController self = new BookmarkController();

        self.setSize( WINDOW_WIDTH, WINDOW_HEIGHT );
        self.setTitle("Bookmark Controller");
        
        self.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        self.setVisible(true);

        self.begin();
    }
    
}