Question

我试图添加一个while循环来计算尝试次数，并将其添加到GUI中的消息中。添加while循环后，程序将冻结，但不会向控制台输出错误。

我已经在没有GUI的情况下对其进行了测试，并且可以使用System.out.print很好地进行打印，但是我什至无法允许第二次输入。我必须停止运行代码才能退出。

任何建议将不胜感激！

import javax.swing.JFrame;
import javax.swing.JLabel;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.util.*;
import javax.swing.SwingConstants;
import java.awt.Font;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class GuessingGame extends JFrame {
private JTextField txtGuess;
private JLabel lblOutput;
private int theNumber;
private int attempt;
public void checkGuess() {
    String guessText = txtGuess.getText();
    String message = "";
    try {

        int guess = Integer.parseInt(guessText);
        while(guess!=theNumber) {
            if (guess < 0 || guess >100) {
                message = "Please enter a number between 0 and 100";
                attempt++;
            }
            else if (guess < theNumber) {
                message = guess + " is too low. Try again.";
                attempt++;
            }
            else if (guess > theNumber) {
                message = guess + " is too high. Try again.";
                attempt++;
            }
            else {
                message = guess + " is correct! It took " + attempt+ " attempts. Starting new game.";
                attempt++;
                newGame();
            }
        }
    } 
        catch(Exception e) {
        message= "Enter a whole number between 0 and 100";
    } 
        finally {
            lblOutput.setText(message);
            txtGuess.requestFocus();
            txtGuess.selectAll();
        }
}
public void newGame() {
    theNumber = (int)(Math.random() * 100 + 1);
    }

public GuessingGame() {
    setTitle("Hi-Lo Guessing Game");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    getContentPane().setLayout(null);

    JLabel lblHiloGuessingGame = new JLabel("Hi-Lo Guessing Game");
    lblHiloGuessingGame.setFont(new Font("Tahoma", Font.BOLD, 15));
    lblHiloGuessingGame.setHorizontalAlignment(SwingConstants.CENTER);
    lblHiloGuessingGame.setBounds(12, 35, 408, 16);
    getContentPane().add(lblHiloGuessingGame);

    JLabel lblGuessANumber = new JLabel("Guess a number between 1 and 100");
    lblGuessANumber.setHorizontalAlignment(SwingConstants.CENTER);
    lblGuessANumber.setBounds(58, 86, 245, 16);
    getContentPane().add(lblGuessANumber);

    txtGuess = new JTextField();
    txtGuess.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            checkGuess();
        }
    });
    txtGuess.setBounds(310, 85, 32, 19);
    getContentPane().add(txtGuess);
    txtGuess.setColumns(10);

    JButton btnGuess = new JButton("Guess!");
    btnGuess.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
        checkGuess();
        }
        });
    btnGuess.setBounds(163, 137, 97, 25);
    getContentPane().add(btnGuess);

    lblOutput = new JLabel("Enter a number and click guess");
    lblOutput.setHorizontalAlignment(SwingConstants.CENTER);
    lblOutput.setFont(new Font("Tahoma", Font.ITALIC, 13));
    lblOutput.setBounds(84, 197, 265, 19);
    getContentPane().add(lblOutput);
}

public static void main(String[] args) {
    GuessingGame theGame = new GuessingGame();
    theGame.newGame();
    theGame.setSize(new Dimension(450,300));
    theGame.setVisible(true);
    }

}

Answer 1

我认为您不需要为文本字段执行由操作执行的处理程序，因为对文本字段执行任何操作都不应算作尝试，对吧？仅按Guess按钮才算是尝试。

因此您可以删除它：

txtGuess.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        checkGuess();
    }
});

现在，只要用户按下按钮，就会调用checkGuess。现在，它将解析文本字段中的数字，并进入while循环以检查该数字。但是，由于guess从未在while循环中被修改，因此while循环永不中断。

即使您在while循环中读取了guess，guess仍然不会改变，因为在while循环运行时，用户无法与进行交互用户界面。

一种更好的方法是简单地删除while循环：

public void checkGuess() {
    String guessText = txtGuess.getText();
    String message = "";
    try {

        int guess = Integer.parseInt(guessText);
        if (guess < 0 || guess >100) {
            message = "Please enter a number between 0 and 100";
            attempt++;
        }
        else if (guess < theNumber) {
            message = guess + " is too low. Try again.";
            attempt++;
        }
        else if (guess > theNumber) {
            message = guess + " is too high. Try again.";
            attempt++;
        }
        else {
            message = guess + " is correct! It took " + attempt+ " attempts. Starting new game.";
            attempt++;
            newGame();
        }
    } 
        catch(Exception e) {
        message= "Enter a whole number between 0 and 100";
    } 
        finally {
            lblOutput.setText(message);
            txtGuess.requestFocus();
            txtGuess.selectAll();
        }
}

尽管似乎您需要在此处进行while循环，但实际上并不需要。这是因为每次您按下Guess按钮时都会调用checkGuess。

与在命令行中不同，您不询问在GUI程序中输入，而是等待。

程序/ GUI在添加while循环后冻结

1 个答案: