在 ActionListener 中调用

Question

目前我正在尝试将我的代码插入我的 GUI让它在我的 GUI 中工作......但目前我只是想考虑 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

文本 JTextField 变量在构造函数内部声明，并且对类的其他方法不可见，因为它没有类“范围”。您需要通过在类中声明此变量而不是构造函数来使该变量成为类字段，以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);

Answer 2

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。

你可以像这样使用匿名内部类来添加事件监听器：

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);