Java程序 报错。高手 看下 哪里有问题。

import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JPanel; 
import javax.swing.JLabel;
import javax.swing.JButton;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Color;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent; 

/**
简易计算器 包括 加法 减法
*/
public class calculator extends JFrame implements ActionListener
{
	public static final int WIDTH=400;
	public static final int HEIGHT=200;
	public static final int NUMBER_OF_DIGITS=30;
	
	private JTextField ioField;
	private double result=0.0 ;

	public static void main (String[] args)
	{
		calculator aCalculator=new calculator();
		aCalculator.setVisible(true);
	}
	
	public calculator()
	{
		setTitle("Simplified Calculator");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );
		setSize(WIDTH,HEIGHT);
		setLayout(new BorderLayout());
		
		JPanel textPanel=new JPanel();
		textPanel.setLayout(new FlowLayout());
		ioField=new JTextField("Enter numbers here.",NUMBER_OF_DIGITS);
		ioField.setBackground(Color.WHITE);
		textPanel.add(ioField);
		add(textPanel,BorderLayout.NORTH );
		
		JPanel buttonPanel=new JPanel();
		buttonPanel.setBackground(Color.BLUE );
		buttonPanel.setLayout(new FlowLayout());
		
		JButton addButton=new JButton("+");
		addButton.addActionListener(this);
		buttonPanel.add(addButton);
		JButton subtractButton=new JButton("-");
		subtractButton.addActionListener(this);
		buttonPanel.add(subtractButton);
		JButton resultButton=new JButton("=");
		resultButton.addActionListener(this);
		buttonPanel.add(resultButton);
		JButton resetButton=new JButton("Reset");
		resetButton.addActionListener(this);
		buttonPanel.add(resetButton);
		
		add(buttonPanel,BorderLayout.CENTER );
	}
	
	public void actionPerformed(ActionEvent e)
	{
		try
		{
			assumingCorrectNumberFormates(e);
		}
		catch (NumberFormatException e2)
		{
			ioField.setText("Error:Reenter Number.");
		}
	}

	public void assumingCorrectNumberFormates(ActionEvent e)
	{
		String actionCommand=e.getActionCommand();
		
		if (actionCommand.equals("+"))
		{
			result=result+stringToDouble(ioField.getText());
			ioField.setText(Double.toString(result));
		}
		else if(actionCommand.equals("-"))
		{
			result=result-stringToDouble(ioField.getText());
			ioField.setText(Double.toString(result));
		}
		else if(actionCommand.equals("="))
		{
			ioField.setText(Double.toHexString(result));
		}
		else if(actionCommand.equals("Reset"))
		{
			result=0.0;
			ioField.setText("0.0");
		}
		else
			ioField.setText("Unexpected error.");
	}
	
	private static double stringToDouble(String stringObject)
	{
		return Double.parseDouble(stringObject.trim());
	}
}

答案：看一下Test_DataManager.java的53行。是不是有Integer.parseInt(); 这里括号里的值现在是空字符串， 你让他变成有值就可以了。 很明显了，test.

其他：请问，控制台报错的信息在哪呢？ import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JPanel; 
import javax.swing.JLabel;
import javax.swing.JButton;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Color;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent; 

/**
简易计算器 包括 加法 减法
*/
public class calculator extends JFrame implements ActionListener
{
	/**
	 * 
	 */
	private static final long serialVersionUID = 2681191641845989494L;
	public static final int WIDTH=400;
	public static final int HEIGHT=200;
	public static final int NUMBER_OF_DIGITS=30;
	
	private JTextField ioField;
	private double result=0.0 ;

	public static void main (String[] args)
	{
		calculator aCalculator=new calculator();
		aCalculator.setVisible(true);
	}
	
	public calculator()
	{
		setTitle("Simplified Calculator");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );
		setSize(WIDTH,HEIGHT);
		setLayout(new BorderLayout());
		
		JPanel textPanel=new JPanel();
		textPanel.setLayout(new FlowLayout());
		ioField=new JTextField("Enter numbers here.",NUMBER_OF_DIGITS);
		ioField.setBackground(Color.WHITE);
		textPanel.add(ioField);
		add(textPanel,BorderLayout.NORTH );
		
		JPanel buttonPanel=new JPanel();
		buttonPanel.setBackground(Color.BLUE );
		buttonPanel.setLayout(new FlowLayout());
		
		JButton addButton=new JButton("+");
		addButton.addActionListener(this);
		buttonPanel.add(addButton);
		JButton subtractButton=new JButton("-");
		subtractButton.addActionListener(this);
		buttonPanel.add(subtractButton);
		JButton resultButton=new JButton("=");
		resultButton.addActionListener(this);
		buttonPanel.add(resultButton);
		JButton resetButton=new JButton("Reset");
		resetButton.addActionListener(this);
		buttonPanel.add(resetButton);
		
		add(buttonPanel,BorderLayout.CENTER );
	}
	
	public void actionPerformed(ActionEvent e)
	{
		try
		{
			assumingCorrectNumberFormates(e);
		}
		catch (NumberFormatException e2)
		{
			ioField.setText("Error:Reenter Number.");
		}
	}

	public void assumingCorrectNumberFormates(ActionEvent e)
	{
		String actionCommand=e.getActionCommand();
		
		if (actionCommand.equals("+"))
		{
			result=result+stringToDouble(ioField.getText());
			ioField.setText(Double.toString(result));
		}
		else if(actionCommand.equals("-"))
		{
			result=result-stringToDouble(ioField.getText());
			ioField.setText(Double.toString(result));
		}
		else if(actionCommand.equals("="))
		{
			ioField.setText(Double.toHexString(result));
		}
		else if(actionCommand.equals("Reset"))
		{
			result=0.0;
			ioField.setText("0.0");
		}
		else
			ioField.setText("Unexpected error.");
	}
	
	private static double stringToDouble(String stringObject)
	{
		return Double.parseDouble(stringObject.trim());
	}
} 

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