public void paint（Graphics g）不是为double绘制，而是为string绘制，我想将string转换为double。
所以我试图做一个堆栈计算器，我使用链表来做它与双打的一部分，油漆是不做我想要的。我想要的是，我有按钮举行的加法和除法等。我试图在一个数字，它会画它马上在我的窗口，它没有这样做。我使用Eclipse。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import NumberTree.Ornament;
import java.util.Iterator;
import java.util.LinkedList;

public class StackCalc extends JFrame implements ActionListener {
    private   LinkedList<Double> values;
    double value1 , value2 ;

    JTextField theTextField;
    JButton boxButton;

    public static void main ( String[] args) {
         new StackCalc();
    }

    public StackCalc() {
        setDefaultCloseOperation( EXIT_ON_CLOSE );

        setLayout( new FlowLayout());
        setTitle("StackCalc");
        setSize(new Dimension(600,600));

        boxButton = new JButton("add");
        add(boxButton);
        boxButton.addActionListener( this );
        boxButton = new JButton("multi");
        add(boxButton);
        boxButton.addActionListener( this );
        boxButton = new JButton("divide");
        add(boxButton);
        boxButton.addActionListener( this );
        boxButton = new JButton("subt");
        add(boxButton);
        boxButton.addActionListener( this );

        theTextField = new JTextField("Write Something ");
        add(theTextField);
        theTextField.addActionListener( this );

        values = new LinkedList<Double>(); // make the stack
        setVisible(true);
  }

public void actionPerformed(ActionEvent e) {
    if  ( e.getSource()==theTextField )  {
        value1 = Double.parseDouble(theTextField.getText());
        values.push(value1);
      }
}

public void add() {//return nothing
    value1=values.pop();
    value2=values.pop();
    values.push (value1 + value2);
}

public void multi() { //return nothing
    value1=values.pop();
    value2=values.pop();
    values.push (value1 * value2);
}

public void divide() {//return nothing
    value1=values.pop();
    value2=values.pop();
    values.push (value1 / value2);
}

public void subt() {//return nothing
    value1=values.pop();
    value2=values.pop();
    values.push (value1 - value2);
}

public void paint( Graphics g ) {
    Iterator it = values.iterator();
    while (it.hasNext()) {
        double d = (Double)(it.next()); 
        Double d1 = (Double)(it.next()); 
        System.out.println("d="+d + d1 );

        super.paint(g);
        //((LinkedList) values).paint(g);
        //values = LinkedList.paint(g);

        g.create(29, 40, 100, 200); // at the bottom of the screen
        //g.drawString( value2, 50,420 ); 
       //g.drawString( values, 50,480 );    
    }
}