ActionListener中的java调用

Question

我正在尝试将我的代码插入到我的GUI中，现在我找不到一种方法来调用ActionListener中的文本，而不中断我的代码。我知道findAndReplace（）中有一些东西我需要处理才能使它在我的GUI中工作。。。但现在我只是想解释一下ActionListener

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;

import javax.swing.*;



public class HangmanPanel extends JPanel {
    static Boolean FOUND;
    private static final long serialVersionUID = -5793357804828609325L;

    public static String answerKey() {
        //get random array element
        String array[] = new String[10];
        array[0] = "hamlet";
        array[1] = "mysts of avalon";
        array[2] = "the iliad";
        array[3] = "tales from edger allan poe";
        array[4] = "the children of hurin";
        array[5] = "the red badge of courage";
        array[6] = "of mice and men";
        array[7] =  "utopia"; 
        array[8] =  "chariots of the gods";
        array[9] =  "a brief history of time";

        ArrayList<String> list = new ArrayList<String>(Arrays.asList(array));
        Collections.shuffle(list);
        String s = list.get(0);
        return s;
    }

    public StringBuilder dashReplace(String s) {
        //replace non-white space char with dashes and creates StringBuilder Object
        String tW = s.replaceAll("\\S", "-"); 
        System.out.print(tW + "\n");  
        StringBuilder AnswerKey = new StringBuilder(tW);
        return AnswerKey;
    }





    public HangmanPanel(){
        this.setLayout(null);

        JLabel heading = new JLabel("Welcome to the Hangman App");
        JButton Button = new JButton("Ok");
        //get input
        Button.addActionListener(new input()); 

        JLabel tfLable = new JLabel("Please Enter a Letter:");


        JLabel AnswerKey = new JLabel(dashReplace(answerKey()).toString());

        JTextField text = new JTextField(10);


        heading.setSize(200, 50);
        tfLable.setSize(150, 50);
        text.setSize(50, 30);
        Button.setSize(60, 20);
        AnswerKey.setSize(200, 100);

        heading.setLocation(300, 10);
        tfLable.setLocation(50, 40);
        text.setLocation(50, 80);
        Button.setLocation(100, 85);
        AnswerKey.setLocation(100,85);

        this.add(heading);
        this.add(tfLable);
        this.add(text);
        this.add(Button);
        this.add(AnswerKey);
    }
    public class input implements ActionListener{

        @Override
        public void actionPerformed(ActionEvent e) {
            // can't access text
            sc = text.getText();
            char ch = sc.charAt(0);
            findAndReplace(s, AnswerKey, input, ch);
        }


    } 
    public static int findAndReplace(String s, StringBuilder AnswerKey, String sc,
            char ch) {
        //find position of user input and replace
        int pos = -1;
        FOUND = false;
        while(true){
        pos = s.indexOf(sc, pos+1);
        if(pos < 0){

            break;
        }else{
            FOUND = true;
            AnswerKey.setCharAt(pos, ch);
        }

        }
        System.out.println(AnswerKey);
        return pos;
    }

}

Answer 1

首先不要使用小写的类名和大写的变量名，你的代码真的很难读

您可以使用匿名内部类添加事件侦听器，如下所示：

Button.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        // can't access text
        sc = text.getText();
        char ch = sc.charAt(0);
        findAndReplace(s, AnswerKey, input, ch);
    }
});

将text变量标记为final，以便在匿名类中访问它：

final JTextField text = new JTextField(10);

Answer 2

文本JTextField变量在构造函数中声明，并且对类的其他方法不可见，因为它没有类“作用域”。您需要通过在类中声明该变量，而不是在构造函数中声明该变量，使其成为类字段，以便使其在整个类中可见

例如：

public class HangmanPanel extends JPanel {
   private static final long serialVersionUID = -5793357804828609325L;
   private Boolean found; // this should not be static nor capitalized
   private JTextField text; // declare your class field

   // .... etc...

   public HangmanPanel() {
      this.setLayout(null);  // *** don't do this. Use layout managers.

      // ... etc

      // JTextField text = new JTextField(10);
      text = new JTextField(10);