Question

继承我的代码人员。我已经回顾过这个并且不确定为什么在点击JButton后它不会在JTextArea中输出Celcius温度，它应该从JTextField接收它的输入。

继承代码......

import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class C_to_F extends JFrame {

    JPanel layout = new JPanel();
    JLabel title = new JLabel("<html>Welcome to Farenheit to Celcius!</html>");
    JLabel inputtxt = new JLabel("<html>Input Farenheit:</html>");
    static JTextField input = new JTextField (null);
    static JTextArea answer = new JTextArea();
    static JButton submit = new JButton("Submit");

    public static void main(String[] args) {
        JFrame frame = new C_to_F();
        frame.show();   
    }       

    public static void submit() {
        submit.addActionListener(new ActionListener() { 
            public void actionPerformed(ActionEvent e) { 
                input();
            } 
        });
    }

    public static void input() {
        String TextBox = input.getText();
        float farenheit = Float.parseFloat(TextBox);
        for(int i=0;i<=0;i++) {
            double celcius = (farenheit - 32) * 5/9;
            String celciustxt = ("Celcius = " + celcius);
            answer.setText(String.valueOf(celciustxt));             
        }
    }

    public C_to_F() {
        setTitle("Farenheit to Celcius");
        setSize(300,300);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setResizable(true);
        layout.setBorder(BorderFactory.createEmptyBorder(10,10,10,10)); 
        layout.setLayout(new GridLayout(8,1));          

        inputtxt.setHorizontalTextPosition(SwingConstants.CENTER);
        title.setHorizontalTextPosition(SwingConstants.CENTER);

        add(layout);

        layout.add(title);
        layout.add(inputtxt);
        layout.add(input);
        layout.add(submit);
        layout.add(answer);

        setVisible(true);
    }    
}

谢谢你们！

Answer 1

您尚未调用submit()将听众添加到按钮

Answer 2

您永远不会调用submit方法ActionListener和submit按钮

Answer 3

您需要在按钮上注册监听器，例如：

submit.addActionListener(...);
layout.add(submit);

Answer 4

我稍微修改了你的代码。看看是否有效

public class C_to_F extends JFrame{
JPanel layout = new JPanel();
JLabel title = new JLabel("<html>Welcome to Farenheit to Celcius!</html>");
JLabel inputtxt = new JLabel("<html>Input Farenheit:</html>");
static JTextField input = new JTextField (null);
static JTextArea answer = new JTextArea();
static JButton submit = new JButton("Submit");



public static void main(String[] args) {
    JFrame frame = new C_to_F();
    frame.pack();
    frame.setVisible(true);
}


public static void input() {
    String TextBox = input.getText();
    float farenheit = Float.parseFloat(TextBox);
    for(int i=0;i<=0;i++) {
        double celcius = (farenheit - 32) * 5/9;
        String celciustxt = ("Celcius = " + celcius);
        answer.setText(String.valueOf(celciustxt));


    }
}

public C_to_F() {
    setTitle("Farenheit to Celcius");
    setSize(300,300);
    setLocationRelativeTo(null);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setResizable(true);
    layout.setBorder(BorderFactory.createEmptyBorder(10,10,10,10)); 
    layout.setLayout(new GridLayout(8,1));


    inputtxt.setHorizontalTextPosition(SwingConstants.CENTER);
    title.setHorizontalTextPosition(SwingConstants.CENTER);

    submit.addActionListener(new ActionListener() { 
        public void actionPerformed(ActionEvent e) { 
            input();
            SwingUtilities.updateComponentTreeUI(layout);
        } 
    });

    add(layout);

    layout.add(title);
    layout.add(inputtxt);
    layout.add(input);
    layout.add(submit);
    layout.add(answer);

    setVisible(true);


}
}

在Java中单击按钮时，文本区域不打印输入

4 个答案: