接受JSpinner中的测量单位作为输入

Question

我有一个数字JSpinner，它接受特定度量单位中的值。现在，我想要一种特殊的JSpinner行为：如果用户输入一个数字值并附加一个特定的度量单位字符串（例如“ inch”，“ pica”），则必须将输入的数字值转换为另一个值（取决于在单位字符串上）。当用户离开微调框（失去焦点）或以任何方式发生“ commitEdit”时，都必须进行此转换。

我已经尝试了几种变体：自定义文档过滤器，自定义格式实例和微调器的JFormattedTextField的自定义文本字段文档。但是我没有发现“钩住” JFormattedTextField的“ commitEdit”方法调用的任何可能性。

实现我的要求的最佳方法是什么？有一个简单的方法吗？

Answer 1

还有其他一些事情[使您可以在提交用户输入之前对其进行修改：它是commitEdit方法本身（在JFormattedTextField的DefaultEditor的JSpinner中）。在commitEdit内部，您可以看到stringToValue的JFormattedTextField的方法AbstractFormatter被调用。这意味着，如果将自己的自定义AbstractFormatter赋予文本字段，则可以将任何字符串转换为值，并将值转换为任何字符串。这是发生异常的地方，以指示提交是否失败。

因此，按照您的要求，遵循处理不同单位的自定义AbstractFormatter：

import java.text.ParseException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.swing.JFormattedTextField;
import javax.swing.JFormattedTextField.AbstractFormatter;
import javax.swing.JFormattedTextField.AbstractFormatterFactory;
import javax.swing.JFrame;
import javax.swing.JSpinner;
import javax.swing.JSpinner.DefaultEditor;
import javax.swing.SpinnerNumberModel;

public class MilliMeterMain {

    public static enum Unit {
        MM(1), //Millimeters.
        IN(25.4), //Inches (1 inch == 25.4 mm).
        FT(25.4 * 12), //Feet (1 foot == 12 inches).
        YD(25.4 * 12 * 3); //Yards (1 yard == 3 feet).

        private final double factorToMilliMeters; //How much of this Unit composes a single millimeter.

        private Unit(final double factorToMilliMeters) {
            this.factorToMilliMeters = factorToMilliMeters;
        }

        public double getFactorToMilliMeters() {
            return factorToMilliMeters;
        }

        public double toMilliMeters(final double ammount) {
            return ammount * getFactorToMilliMeters();
        }

        public double fromMilliMeters(final double ammount) {
            return ammount / getFactorToMilliMeters();
        }
    }

    public static class UnitFormatter extends AbstractFormatter {

        private static final Pattern PATTERN;

        static {
            //Building the Pattern is not too tricky. It just needs some attention.

            final String blank = "\\p{Blank}"; //Match any whitespace character.
            final String blankGroupAny = "(" + blank + "*)"; //Match any whitespace character, zero or more times and group them.

            final String digits = "\\d"; //Match any digit.
            final String digitsGroup = "(" + digits + "+)"; //Match any digit, at least once and group them.
            final String digitsSuperGroup = "(\\-?" + digitsGroup + "\\.?" + digitsGroup + "?)"; //Matches for example "-2.4" or "2.4" or "2" or "-2" in the same group!

            //Create the pattern part which matches any of the available units...
            final Unit[] units = Unit.values();
            final StringBuilder unitsBuilder = new StringBuilder(Pattern.quote("")); //Empty unit strings are valid (they default to millimeters).
            for (int i = 0; i < units.length; ++i)
                unitsBuilder.append('|').append(Pattern.quote(units[i].name()));
            final String unitsGroup = "(" + unitsBuilder + ")";

            final String full = "^" + blankGroupAny + digitsSuperGroup + blankGroupAny + unitsGroup + blankGroupAny + "$"; //Compose full pattern.

            PATTERN = Pattern.compile(full);
        }

        private Unit lastUnit = Unit.MM;

        @Override
        public Object stringToValue(final String text) throws ParseException {
            if (text == null || text.trim().isEmpty())
                throw new ParseException("Null or empty text.", 0);
            try {
                final Matcher matcher = PATTERN.matcher(text.toUpperCase());
                if (!matcher.matches())
                    throw new ParseException("Invalid input.", 0);
                final String ammountStr = matcher.group(2),
                             unitStr = matcher.group(6);
                final double ammount = Double.parseDouble(ammountStr);
                lastUnit = unitStr.trim().isEmpty()? null: Unit.valueOf(unitStr);
                return lastUnit == null? ammount: lastUnit.toMilliMeters(ammount);
            }
            catch (final IllegalArgumentException iax) {
                throw new ParseException("Failed to parse input \"" + text + "\".", 0);
            }
        }

        @Override
        public String valueToString(final Object value) throws ParseException {
            final double ammount = lastUnit == null? (Double) value: lastUnit.fromMilliMeters((Double) value);
            return String.format("%.4f", ammount).replace(',', '.') + ((lastUnit == null)? "": (" " + lastUnit.name()));
        }
    }

    public static class UnitFormatterFactory extends AbstractFormatterFactory {
        @Override
        public AbstractFormatter getFormatter(final JFormattedTextField tf) {
            if (!(tf.getFormatter() instanceof UnitFormatter))
                return new UnitFormatter();
            return tf.getFormatter();
        }
    }

    public static void main(final String[] args) {
        final JSpinner spin = new JSpinner(new SpinnerNumberModel(0d, -1000000d, 1000000d, 1d)); //Default numbers in millimeters.

        ((DefaultEditor) spin.getEditor()).getTextField().setFormatterFactory(new UnitFormatterFactory());

        final JFrame frame = new JFrame("JSpinner infinite value");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(spin);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

我使用测量长度（毫米，英寸，英尺和码）的单位。但是您可以根据自己的需要进行调整。
注意，在以上实现中，SpinnerNumberModel仅知道毫米。 AbstractFormatter可以将毫米转换为其他单位，也可以转换成毫米（根据用户的输入）。这意味着当您将单位设置为
YD

（即码）时，模型仍将旋转毫米，但JFormattedTextField将以码的分数旋转。试试看，了解我的意思。这意味着getValue() / JSpinner的SpinnerNumberModel将始终返回毫米的量，而不管文本字段中的单位是什么（AbstractFormatter始终进行转换）。作为第二种情况，如果需要，可以将转换移到AbstractFormatter之外。例如，您可以让用户在微调器中输入一个始终与测量单位无关的值。这样，用户始终会看到值旋转等于1的步长（在此示例中），同时AbstractFormatter将保留用户设置为旋转器的最后一个单位的属性。因此，现在当您从JSpinner / SpinnerNumberModel中获取值时，您将获得一个与单位无关的数字，然后使用设置为AbstractFormatter的最后一个单位来确定用户要使用的单位。这与使用微调器有些不同，可能更方便。

这是第二种情况的代码：

import java.text.ParseException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.swing.JFormattedTextField;
import javax.swing.JFormattedTextField.AbstractFormatter;
import javax.swing.JFormattedTextField.AbstractFormatterFactory;
import javax.swing.JFrame;
import javax.swing.JSpinner;
import javax.swing.JSpinner.DefaultEditor;
import javax.swing.SpinnerNumberModel;

public class StepMain {

    public static enum Unit {
        MM, //Milimeters.
        IN, //Inches (1 inch == 25.4 mm).
        FT, //Feet (1 foot == 12 inches).
        YD; //Yards (1 yard == 3 feet).
    }

    public static class UnitFormatter extends AbstractFormatter {

        private static final Pattern PATTERN;

        static {
            //Building the Pattern is not too tricky. It just needs some attention.

            final String blank = "\\p{Blank}"; //Match any whitespace character.
            final String blankGroupAny = "(" + blank + "*)"; //Match any whitespace character, zero or more times and group them.

            final String digits = "\\d"; //Match any digit.
            final String digitsGroup = "(" + digits + "+)"; //Match any digit, at least once and group them.
            final String digitsSuperGroup = "(\\-?" + digitsGroup + "\\.?" + digitsGroup + "?)"; //Matches for example "-2.4" or "2.4" or "2" or "-2" in the same group!

            //Create the pattern part which matches any of the available units...
            final Unit[] units = Unit.values();
            final StringBuilder unitsBuilder = new StringBuilder(Pattern.quote("")); //Empty unit strings are valid (they default to milimeters).
            for (int i = 0; i < units.length; ++i)
                unitsBuilder.append('|').append(Pattern.quote(units[i].name()));
            final String unitsGroup = "(" + unitsBuilder + ")";

            final String full = "^" + blankGroupAny + digitsSuperGroup + blankGroupAny + unitsGroup + blankGroupAny + "$"; //Compose full pattern.

            PATTERN = Pattern.compile(full);
        }

        private Unit lastUnit = Unit.MM;

        @Override
        public Object stringToValue(final String text) throws ParseException {
            if (text == null || text.trim().isEmpty())
                throw new ParseException("Null or empty text.", 0);
            try {
                final Matcher matcher = PATTERN.matcher(text.toUpperCase());
                if (!matcher.matches())
                    throw new ParseException("Invalid input.", 0);
                final String ammountStr = matcher.group(2),
                             unitStr = matcher.group(6);
                final double ammount = Double.parseDouble(ammountStr);
                lastUnit = Unit.valueOf(unitStr);
                return ammount;
            }
            catch (final IllegalArgumentException iax) {
                throw new ParseException("Failed to parse input \"" + text + "\".", 0);
            }
        }

        @Override
        public String valueToString(final Object value) throws ParseException {
            return String.format("%.3f", value).replace(',', '.') + ' ' + lastUnit.name();
        }
    }

    public static class UnitFormatterFactory extends AbstractFormatterFactory {
        @Override
        public AbstractFormatter getFormatter(final JFormattedTextField tf) {
            if (!(tf.getFormatter() instanceof UnitFormatter))
                return new UnitFormatter();
            return tf.getFormatter();
        }
    }

    public static void main(final String[] args) {
        final JSpinner spin = new JSpinner(new SpinnerNumberModel(0d, -1000000d, 1000000d, 0.001d));

        ((DefaultEditor) spin.getEditor()).getTextField().setFormatterFactory(new UnitFormatterFactory());

        final JFrame frame = new JFrame("JSpinner infinite value");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(spin);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

关于您所说的语言环境，如果我理解正确，您希望逗号和点都在同一微调器中运行吗？如果是这样，您可以检查答案here恰好与此有关。在那种情况下，仍然可以通过使用自定义AbstractFormatter解决问题。