getdouble.java

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import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class getDouble extends Applet implements ActionListener
{
	Label prompt;
	TextField input;
	double d =0.0;
	
	public void init()
	{
		prompt = new Label("请输入一个浮点数");
		input = new TextField(10);
		add(prompt);
		add(input);
		input.addActionListener(this);
	}
	public void paint(Graphics g)
	{
		g.drawString("你输入了数据："+d,10,50);
	}
	public void actionPerformed(ActionEvent e)
	{
		d = Double.valueOf(input.getText()).doubleValue();
		repaint();
	}
}