labeldemo.java

此文件能系统的介绍Java初级知识

package swing.label;

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

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

import swing.WindowDestroyer;


/**
 Class to demonstrate placing a label on a text field.
*/
public class LabelDemo extends JFrame implements ActionListener
{

	public static final int WIDTH = 300;
    public static final int HEIGHT = 200;

    private JTextField name;

    public LabelDemo( )
    {
        setTitle("Name Tester");
        setSize(WIDTH, HEIGHT);
        addWindowListener(new WindowDestroyer( ));
        Container content = getContentPane( );
        content.setLayout(new GridLayout(2, 1));

        JPanel namePanel = new JPanel( );
        namePanel.setLayout(new BorderLayout( ));
        namePanel.setBackground(Color.LIGHT_GRAY);

        name = new JTextField(20);
        namePanel.add(name, BorderLayout.SOUTH);
        JLabel nameLabel = new JLabel("Enter your name here:");
        namePanel.add(nameLabel, BorderLayout.CENTER);

        content.add(namePanel);

        JPanel buttonPanel = new JPanel( );
        buttonPanel.setLayout(new FlowLayout( ));
        JButton b = new JButton("Test");
        b.addActionListener(this);
        buttonPanel.add(b);
        b = new JButton("Clear");
        b.addActionListener(this);
        buttonPanel.add(b);

        content.add(buttonPanel);
    }

    public void actionPerformed(ActionEvent e)
    {
        if (e.getActionCommand( ).equals("Test"))
            name.setText("A very good name!");
        else if (e.getActionCommand( ).equals("Clear"))
            name.setText("");
        else
            name.setText("Error in window interface.");
    }


    public static void main(String[] args)
    {
        LabelDemo w = new LabelDemo( );
        w.setVisible(true);
    }


}