如何在我的Applet中阻止我的计数变量不正确递增？

Question

我在我的Applet中使用一个按钮来向LinkedList添加单词。但目前它无法正常工作。似乎每次选择“添加单词”按钮时，它都会保留前一个数字作为计数值，并且以旧值递增，而不是每次都以1为单位递增。这会导致在选择搜索按钮并输出错误的编号时打印错误的值。尽管已选择“添加单词”次数，但如何让count变量保持正确的值。

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.*; 
import java.util.LinkedList; 
import java.util.ListIterator; 

/** 
* Created by joshuaogunnote on 31/10/2015. 
*/ 

public class Applet2 extends JApplet { 

    private String text; 
    private int text1; 
    JTextField value1, value2; 
    LinkedList<String> list = new LinkedList<String>(); 
    public JLabel jLabel; 
    public int count = 0; 
    public int search_count = 0; 

    public void init() { 

     JLabel prompt = new JLabel("Please enter a word"); 
     JLabel prompt1 = new JLabel("Please enter a certain letter"); 

     value1 = new JTextField(10); 
     value2 = new JTextField(10); 

     JPanel textPanel = new JPanel(); 
     textPanel.add(prompt); 
     textPanel.add(value1); 
     add(textPanel, BorderLayout.NORTH); 
     textPanel.add(prompt1); 
     textPanel.add(value2); 


     JPanel centrePanel = new JPanel(); 
     text = ""; 
     jLabel = new JLabel(text); 
     centrePanel.add(jLabel); 
     add(centrePanel, BorderLayout.CENTER); 


     JButton but = new JButton("Add word"); 
     JButton but1 = new JButton("Clear"); 
     JButton but2 = new JButton("Remove first occurrence"); 
     JButton but3 = new JButton("Remove all occurrences"); 
     JButton but4 = new JButton("Display all words begging with certain letter"); 
     JButton but5 = new JButton("Search"); 

     JPanel butPanel = new JPanel(); 

     butPanel.add(but); 
     butPanel.add(but1); 
     butPanel.add(but5); 
     butPanel.add(but2); 
     butPanel.add(but3); 
     butPanel.add(but4); 


     add(butPanel, BorderLayout.SOUTH); 

     but.addActionListener(new AddHandler(this)); 
     but1.addActionListener(new ClearHandler(this)); 
     but5.addActionListener(new SearchHandler(this)); 
     but2.addActionListener(new RemoveFirstHandler(this)); 


    } 

    class AddHandler implements ActionListener { 

     private Applet2 theApplet; 

     public AddHandler(Applet2 app) { 
      theApplet = app; 
     } 

     public void actionPerformed(ActionEvent e) { 

      text = theApplet.value1.getText(); 


      try { 

       text1 = Integer.parseInt(text); 
       jLabel.setText("ERROR - The string " + "'" + text1 + "'" + " is not a valid word"); 

      } catch (NumberFormatException e1) { 

       if (text.length() != 0) { 
        jLabel.setText("Word " + "'" + text + "'" + " has been added to the list"); 
        list.add(text); 

这是变量。

    count = count + 1; 

       } else { 
        jLabel.setText("ERROR - Please enter a word"); 
       } 

      } 

     } 
    } 

    class ClearHandler implements ActionListener { 

     private Applet2 theApplet; 

     public ClearHandler(Applet2 app) { 
      theApplet = app; 
     } 

     public void actionPerformed(ActionEvent e) { 

      list.clear(); 
      jLabel.setText("List has been cleared"); 
      count = 0; 
      search_count = 0; 

     } 
    } 

    class SearchHandler implements ActionListener { 

     private Applet2 theApplet; 

     public SearchHandler(Applet2 app) { 
      theApplet = app; 
     } 

     public void actionPerformed(ActionEvent e) { 

      String text = theApplet.value1.getText(); 

      ListIterator<String> listIterator = list.listIterator(); 

      while (listIterator.hasNext()) { 


       if (text.equals(listIterator.next())) { 

        search_count = search_count + 1; 

       } 
      } 

      jLabel.setText("Word " + "'" + text + "'" + " was found " + search_count + " time(s) in the list"); 

      if (text.length() == 0) { 

       jLabel.setText("Please enter a word - The total number of words in the list are: " + count); 

      } 

     } 
    } 

    class RemoveFirstHandler implements ActionListener { 

     private Applet2 theApplet; 

     public RemoveFirstHandler(Applet2 app) { 
      theApplet = app; 
     } 
     public void actionPerformed(ActionEvent e) { 

      ListIterator<String> listIterator = list.listIterator(); 

      while (listIterator.hasNext()) { 

       if (text.equals(listIterator.next())) { 

        list.remove(text); 
        jLabel.setText("First occurrence of word " + "'" + text + "'" + " has been deleted"); 
        count = 0; 
        search_count = 0; 
        break; 

       } else { 

        jLabel.setText("ERROR - Word " + "'" + text + "'" + " is not in list"); 
       } 


      } 

     } 

    } 
} 

Answer 1

好的，首先，不要向任何人展示此代码。他们不会留下深刻的印象。有很多方法可以确定输入的单词是不是整数，但使用NumberFormatException不是其中之一。

相反，你应该使用类似：

if(!text.trim().matches("[\\d]+")) { 
    //the text entered is not an Integer. Do your magic here. 
} 

如果您希望输入的文本不包含任何数量在所有使用

Pattern and Matchers 
Pattern pattern = Pattern.comile("[\\d]"); 
Matcher matcher = pattern.matcher(text); 
if(!matcher.find()) { 
    //matcher was unable to find any number in the string 
} 

内部正在维护有效的单词列表您可以拨打list，您可以使用list.size()查找您拥有的有效单词的数量。你不必为此使用单独的计数器。