在Java中单击按钮时，文本区域不打印输入

Question

Heres my code guys. 这是我的代码人员。 I have reviewed this and not sure why it is not outputting the Celcius temperature in the JTextArea once the JButton is clicked which should receive its input from the JTextField. 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。

Heres the code... 继承人代码......

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);
    }    
}

Thanks guys! 多谢你们！

Answer 1

您尚未调用submit()将侦听器添加到按钮

Answer 2

您永远不会调用使用submit按钮注册ActionListener的方法submit

Answer 3

You need to register the Listener on the button, eg: 您需要在按钮上注册监听器，例如：

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

Answer 4

I have modified your code a little. 我稍微修改了你的代码。 See if this works 看看这是否有效

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

问题描述

4 个解决方案

解决方案1
1 2014-05-02 13:41:36

解决方案2
1 2014-05-02 13:41:50

解决方案3
0 2014-05-02 13:43:00

解决方案4
0 2014-05-02 13:47:46

在Java中单击按钮时，文本区域不打印输入

问题描述

4 个解决方案

解决方案1 1 2014-05-02 13:41:36

解决方案2 1 2014-05-02 13:41:50

解决方案3 0 2014-05-02 13:43:00

解决方案4 0 2014-05-02 13:47:46

解决方案1
1 2014-05-02 13:41:36

解决方案2
1 2014-05-02 13:41:50

解决方案3
0 2014-05-02 13:43:00

解决方案4
0 2014-05-02 13:47:46