JTextField从用户获取整数输入，以便在单击JButton时添加

Question

我要构建一个简单的swing UI应用程序，从单独的JTextField中获取用户输入，然后最后单击Button以执行添加以显示在JButton下面的JTextField上。

输入字段(JTextField)接收整数值。

package com.APPOne_G5;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class AppOne_G5 {
private JPanel calculatorFrame;
private JTextField inputField1;
private JTextField inputField2;
private JButton calculateButton;
private JTextField outputField;
private JLabel inputFieldLabel1;
private JLabel inputFieldLabel2;
private JLabel outputFieldLabel;
private int number1, number2;
private int calc = number1 + number2;
public AppOne_G5() {
inputField1.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
number1 = Integer.parseInt(inputField1.getText());
}
});
inputField2.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
number2 = Integer.parseInt(inputField2.getText());
}
});
calculateButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
calc = number1 + number2;
outputField.setText(String.valueOf(number1+number2));
}
});
outputField.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
outputField.setEditable(false);
outputField.setText(String.valueOf(calc));
}
});
}

public static void main(String[] args) {
JFrame app = new JFrame("Group 5 AppOne");
app.setDefaultCloseOperation(app.EXIT_ON_CLOSE);
app.setContentPane(new AppOne_G5().calculatorFrame);
app.setLocationRelativeTo(null);
app.setVisible(true);
app.pack();
}
}

输入要添加的值后得到0。

这是应用程序

的GUI形式

Answer 1

进一步说明，您只需要一个在单击按钮时激活的操作侦听器。下面是一个完整的工作示例，说明它是如何工作的:

public class AppOne_G5 {
private JFrame app = new JFrame("Group 5 AppOne");
private JPanel calculatorFrame = new JPanel();
private JTextField inputField1 = new JTextField("2");
private JTextField inputField2 = new JTextField("5");
private JButton calculateButton = new JButton("Calculate");
private JTextField outputField = new JTextField("   ");
private JLabel inputFieldLabel1 = new JLabel("Enter Integer");
private JLabel inputFieldLabel2 = new JLabel("Enter Integer");;
private JLabel outputFieldLabel = new JLabel("Result");
private int number1, number2;
private int calc;
public AppOne_G5() {
//Add components in order
app.add(calculatorFrame);
app.setDefaultCloseOperation(app.EXIT_ON_CLOSE);
calculatorFrame.add(inputFieldLabel1);
calculatorFrame.add(inputField1);
calculatorFrame.add(inputFieldLabel2);
calculatorFrame.add(inputField2);
calculatorFrame.add(calculateButton);
calculatorFrame.add(outputFieldLabel);
calculatorFrame.add(outputField);
//Create action listener
calculateButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
//Get the inputs
number1 = Integer.parseInt(inputField1.getText());
number2 = Integer.parseInt(inputField2.getText());
System.out.println("number 1: " + number1 + ", number2: " + number2);
//Calculate the output
calc = number1 + number2;
System.out.println("number 1: " + number1 + ", number2: " + number2 + ", calc: "+calc);
//Show the output
outputField.setText(String.valueOf(calc));
}
});
//Show JFrame
app.setVisible(true);
app.pack();
}

public static void main(String[] args) {
new AppOne_G5();
}
}

要调试为什么没有得到预期的输出，可以使用System.out.println("...");。例如，如果您要使用以下代码，那么您可以查看问题是由于calc错误，还是由于number1或number2已经为零:

calc = number1 + number2;
System.out.println("number 1: " + number1 + ", number2: " + number2 + ", calc: "+calc);

一旦你知道问题在哪里，你就可以进一步回到代码中，找出为什么这个值是零。

Answer 2

正如Scorfield所提到的，所有你需要的只是calculateButton上的一个ActionListener。这就是你应该获取用户输入的文本的地方。