java - 难以通过 JButton 激活 BufferedReader

Question

我正在寻找解决此问题的方法:这是我的代码:

import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
import javax.swing.JTextField;

public class Directory{
    public static void main(String args[]) throws IOException{

    JFrame frame = new JFrame("Directory");
    frame.setPreferredSize(new Dimension(300,300));
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    final JProgressBar searchprogress = new JProgressBar();
    JPanel panel = new JPanel();
    final JButton searchbutton = new JButton("Search");
    final JTextField searchfield = new JTextField();
    searchfield.setPreferredSize(new Dimension(100,30));
    searchprogress.setPreferredSize(new Dimension(200, 30));
    searchbutton.setLocation(100, 100);


    /*                  Start Buffered Reader                       */
    BufferedReader br = new BufferedReader(new FileReader("test1.txt"));
    String housetype = br.readLine();
    String housenumber = br.readLine();
    String housestreet = br.readLine();
    String housepostal = br.readLine();
    String houseplace = br.readLine();
    String seperation = br.readLine();
    /*                  Finish Buffered Reader                      */



    /*                      Start Content Code                      */
    JButton done = new JButton("Done");
    done.setVisible(false);
    JLabel housetype_label = new JLabel();
    JLabel housenumber_label = new JLabel();
    JLabel housestreet_label = new JLabel();
    JLabel housepostal_label = new JLabel();
    JLabel houseplace_label = new JLabel();


    /*                      Finish Content Code                     */

    /*                      Start Button Code                       */

    searchbutton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent ae)
        {
            String searchquery = searchfield.getText();
            searchprogress.setValue(100);
            searchfield.setEnabled(false);
            if(searchquery.equals(housetype)){
                System.out.println("We Have Found  A Record!!");
            }}
        });


    /*                      Finish Button Code                      */
    /*                          Test Field                          */


    /*                      End Test Field                          */

    panel.add(searchfield);
    panel.add(done);
    panel.add(searchbutton);
    panel.add(searchprogress);
    frame.add(panel);
    frame.pack();
    frame.setVisible(true);


}
}

基本上，在我写完这段代码后，Eclipse告诉我必须将housetype的修饰符更改为final。这确实不行，因为如果要经历不同的记录，我需要成为一个变化的值。请帮我! D:

Answer 1

这里有多种选择:

• 最快的方法是按照 Eclipse 告诉你的去做，实际上是 Java 告诉你的。为了能够在方法内部的内部类中使用方法局部变量，变量必须是final的。
• 另一种选择是在类定义之后立即将 housetype 变量声明为实例变量。但是，在静态 main 方法中使用它意味着该变量也需要是静态的，这使其成为类变量。

• 另一种方法是保留代码，但声明一个额外的变量，如下所示，然后在内部类中使用 house 变量而不是 housetype。请参阅下面的完整代码:

  public class Directory {
    public static void main(String args[]) throws IOException {
  
      JFrame frame = new JFrame("Directory");
      frame.setPreferredSize(new Dimension(300, 300));
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  
      final JProgressBar searchprogress = new JProgressBar();
      JPanel panel = new JPanel();
      final JButton searchbutton = new JButton("Search");
      final JTextField searchfield = new JTextField();
      searchfield.setPreferredSize(new Dimension(100, 30));
      searchprogress.setPreferredSize(new Dimension(200, 30));
      searchbutton.setLocation(100, 100);
  
      /* Start Buffered Reader */
      final List<String> housetypes = new ArrayList<String>();
      String line = "";
      BufferedReader br = new BufferedReader(new FileReader("test1.txt"));
      while (line != null) {
          line = br.readLine();
          housetypes.add(line);
          String housenumber = br.readLine();
          String housestreet = br.readLine();
          String housepostal = br.readLine();
          String houseplace = br.readLine();
          String seperation = br.readLine();
      }
      /* Finish Buffered Reader */
  
      /* Start Content Code */
      JButton done = new JButton("Done");
      done.setVisible(false);
      JLabel housetype_label = new JLabel();
      JLabel housenumber_label = new JLabel();
      JLabel housestreet_label = new JLabel();
      JLabel housepostal_label = new JLabel();
      JLabel houseplace_label = new JLabel();
  
      /* Finish Content Code */
  
      /* Start Button Code */
      searchbutton.addActionListener(new ActionListener() {
          public void actionPerformed(ActionEvent ae) {
              String searchquery = searchfield.getText();
              searchprogress.setValue(100);
              searchfield.setEnabled(false);
              for (String housetype : housetypes) {
                  if (searchquery.equals(housetype)) {
                      System.out.println("We Have Found  A Record!!");
                  }
              }
          }
      });
  
      /* Finish Button Code */
      /* Test Field */
  
      /* End Test Field */
  
      panel.add(searchfield);
      panel.add(done);
      panel.add(searchbutton);
      panel.add(searchprogress);
      frame.add(panel);
      frame.pack();
      frame.setVisible(true);
    }
  }
  

• 还有更多选项，但这些是最快的。