Question

我正在编写一个GUI程序，它通过使用在单独的Sequence类中定义的迭代或递归方法来计算数字序列中的第n个元素。我想拥有它，以便当用户关闭窗口时，序列的前十个元素将被写入文本文件，以及两种方法的效率，每行都用逗号分隔。

出于某种原因，当我关闭窗口时，文件没有被写入。我已经确定文件已关闭，所以我不确定为什么没有写入文件

GUI

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.*;
import java.util.*;

   public class recursiveGUI extends JPanel 
   { 
   int counterEfficiency;
   private JFrame frame;//The frame
   private JPanel panel;//The panel
   private JRadioButton iterative;
   private JRadioButton recursive;
   private JLabel enter;
   private JTextField enter2;
   private JButton compute;
   private JLabel result;
   private JTextField result2;
   private JLabel efficiency;
   private JTextField efficiency2;
   private ButtonGroup radioButtons;
   public recursiveGUI()
   {

       frame=new JFrame("Project 3");
       panel=new JPanel();
       iterative=new JRadioButton("Iterative");
       recursive=new JRadioButton("Recursive");
       enter=new JLabel("Enter n");
       enter2=new JTextField("");
       compute=new JButton("Compute");
       result=new JLabel("Results");
       result2=new JTextField("");
       efficiency=new JLabel("Efficiency");
       efficiency2=new JTextField("");
       radioButtons=new ButtonGroup();

       frame.addWindowListener(new WindowAdapter(){
           public void windowClosed(WindowEvent e){
            try
            {
                 PrintWriter outFile= new PrintWriter("efResults.txt");
                 for(int n=0;n<=10;n++)
                 {
                     String str=n+",";
                     Sequence.computeIterative(n);
                     str+=Sequence.getEfficiency();
                     Sequence.computeIterative(n);
                     str+=","+Sequence.getEfficiency();
                     outFile.println(str);
                 }
                 outFile.close();

            } 
            catch (FileNotFoundException e1)
            {
                e1.printStackTrace();
            }


           }

       });

       compute.addActionListener(new ActionListener(){
           public void actionPerformed(ActionEvent e){
               int n;

               if(iterative.isSelected())
               {
                   String input=enter2.getText();
                   n=Integer.parseInt(input);
                   result2.setText(Integer.toString(Sequence.computeIterative(n)));
                   efficiency2.setText(Integer.toString(Sequence.getEfficiency()));

               }

               else if(recursive.isSelected())
               {
                   String input=enter2.getText();
                   n=Integer.parseInt(input);
                   result2.setText(Integer.toString(Sequence.computeRecursive(n)));
                   efficiency2.setText(Integer.toString(Sequence.getEfficiency()));
               }

           }
       });


       //Adding the parts together
       panel.setLayout(new GridLayout(6,2));
       radioButtons.add(iterative);
       radioButtons.add(recursive);
       panel.add(new JLabel());panel.add(iterative);
       panel.add(new JLabel());panel.add(recursive);

       panel.add(enter);panel.add(enter2);
       panel.add(new JLabel());panel.add(compute);
       panel.add(result);panel.add(result2);
       panel.add(efficiency);panel.add(efficiency2);
       frame.add(panel);
       frame.pack();
       frame.setLocationRelativeTo(null);
       frame.setSize(600,300);
       frame.setBackground(Color.red);
       frame.setVisible(true);

   }           






   //Main method
   public static void main(String[] args)
   {
       recursiveGUI myGUI=new recursiveGUI();
   }
}

序列类

public class Sequence
{
static int efficiency;
public static int computeIterative(int n)
{
    int result = 0;
    if(n==0)
    {
        result=0;
    }
    else if(n==1)
    {
        result=1;
    }
    else
    {
        int first=1;
        int second=0;
        for(int i=2;i<=n;i++)
        {
            efficiency++;
            result=2*second+first;
            second=first;
            first=result;

        }
    }
    return result;


}

public static int computeRecursive(int n)
{
    int result=0;
    efficiency++;
    if(n==0)
    {
        result=0;
    }
    else if(n==1)
    {
        result=1;
    }
    else
    {
        result=2*computeRecursive(n-1)+computeRecursive(n-2);
    }
    return result;
}

public static int getEfficiency()
{
    int result=efficiency;
    efficiency=0;
    return result;
}

public static void main(String[] args)
{
    computeIterative(5);
}

}

Answer 1

添加 frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); 在收听 windowClosed Event 之前，代码变为：

frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);//////add
frame.addWindowListener(new WindowAdapter(){
    public void windowClosed(WindowEvent e){
       ...
    }

因为setDefaultCloseOperation的默认值是HIDE_ON_CLOSE。有了这个，窗口没有关闭，只是隐藏了。

文件未写入，已关闭文件

1 个答案: