Question

我正在制作一个转换温度的小型Swing小程序：TempConvert.java

这是我的代码：

package swing;

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

/** Celcius to Fahrenheit Converter
 * @version 1.0
 * @author Oliver Ni
 */

public class TempConvert extends JApplet{
    JLabel result;
    JRadioButton ctof;
    JRadioButton ftoc;
    JTextField deg;
    JLabel degLab;
    JButton convert;

    public void convert() {
        if (ctof.isSelected() == true) {
            result.setText("<html><br>" + Integer.toString(Integer.parseInt(deg.getText()) * 9 / 5 + 32) + "<sup>o</sup> F</html>");
        } else if (ftoc.isSelected() == true) {
            result.setText("<html><br>" + Integer.toString((Integer.parseInt(deg.getText()) - 32) * 5 / 9) + "<sup>o</sup> C</html>");
        } else {
            result.setText("<html><br>Error.</html>");
        }
    }

    public void makeApplet() {
        setLayout(new FlowLayout());
        ctof = new JRadioButton("Celcius to Fahrenheit");
        ftoc = new JRadioButton("Fahrenheit to Celcius");
        convert = new JButton("Convert");
        result = new JLabel("");
        ButtonGroup group = new ButtonGroup();
        group.add(ctof);
        group.add(ftoc);

        deg = new JTextField(10);
        degLab = new JLabel("<html><sup>o</sup></html>");
        convert.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                convert();
            }
        });
        add(ctof);
        add(ftoc);
        add(deg);
        add(degLab);
        add(convert);
        add(result);
    }

    public void init() {
        try {
            SwingUtilities.invokeAndWait(new Runnable() {
                public void run() {
                    makeApplet();
                }
            });
        } catch(Exception e) {
            System.out.println("Error loading because " + e);
        }
    }
}

我想将JTextField deg限制为仅整数。我有什么方法可以做到吗？

任何帮助将不胜感激！

Answer 1

“我想将JTextField deg限制为只有整数。”

试试这个。使用文档过滤器

((AbstractDocument) deg.getDocument()).setDocumentFilter(new DocumentFilter() {
            Pattern regEx = Pattern.compile("\\d+");

            @Override
            public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException {
                Matcher matcher = regEx.matcher(text);
                if (!matcher.matches()) {
                    return;
                }
                super.replace(fb, offset, length, text, attrs);
            }
        });

Answer 2

您只需要转换 -

JTextField deg;

到

NumberFormat numberFormat = NumberFormat.getNumberInstance(Locale.getDefault());
DecimalFormat decimalFormat = (DecimalFormat) numberFormat;
decimalFormat.setGroupingUsed(false);
deg = new JFormattedTextField(decimalFormat);
deg.setColumns(15); //whatever size you wish to set

这将返回当前默认语言环境的通用数字格式。

由于

Answer 3

对于像这样的简单程序，您可以尝试使用格式化文本字段：http://docs.oracle.com/javase/tutorial/uiswing/components/formattedtextfield.html

Java Swing JTextField - 仅限数字

3 个答案: