numberfield.java

只能输入数字的JTextField,在java编程里面很有用哦,可以省去验证输入是否为数字额麻烦

import javax.swing.*;
import java.awt.event.*;
class NumberField extends JTextField
{
	public NumberField(int columns)
	{
		super(columns);
		addKeyListener(new KeyAdapter()
		{
			public void keyTyped(KeyEvent e)
			{
				char c = e.getKeyChar();
				if(Character.isDigit(c) || c==KeyEvent.VK_BACK_SPACE || c==KeyEvent.VK_DELETE)
					return;	
				e.consume();
			}
			
			
			public void keyPressed(KeyEvent e)
			{
				if(e.isControlDown()) 
					e.consume();
			}
			

		});

	}
}

class TestNumberField
{
	public static void main(String[] args)
    {
    	JFrame f=new JFrame();
    	f.getContentPane().add(new NumberField(20));
    	f.pack();
    	f.setVisible(true);
    	
    }
}