JFormattedTextField 格式化百分比数字？
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【中文标题】JFormattedTextField 格式化百分比数字？【英文标题】：JFormattedTextField to format percent numbers? 【发布时间】：2011-09-27 13:26:52 【问题描述】：我想使用 JFormattedTextField 将浮点数格式化为百分比值，该字段允许输入从 0% 到 100%（转换为 0.0f-1.0f），始终显示百分号并禁止任何无效字符。
现在我对 NumberFormat.getPercentInstance() 和 NumberFormatter 属性进行了一些试验，但没有成功。
有没有办法使用标准类创建一个遵守这些规则的 JFormattedTextField？还是我必须实现自己的 NumberFormatter？
这就是我目前所拥有的（无法输入 100%，输入 0 会完全破坏它）：
public class MaskFormatterTest
public static void main(String[] args) throws Exception
JFrame frame = new JFrame("Test");
frame.setLayout(new BorderLayout());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
NumberFormat format = NumberFormat.getPercentInstance();
NumberFormatter formatter = new NumberFormatter(format);
formatter.setMaximum(1.0f);
formatter.setMinimum(0.0f);
formatter.setAllowsInvalid(false);
formatter.setOverwriteMode(true);
JFormattedTextField tf = new JFormattedTextField(formatter);
tf.setColumns(20);
tf.setValue(0.56f);
frame.add(tf);
frame.pack();
frame.setVisible(true);
【问题讨论】：
您的默认语言环境是什么，您是否根据该语言环境输入文本？ 附带说明：您可以使用带有 SpinnerNumberModel 的 JSpinner - 这也会更加用户友好。 我的默认语言环境是 DE_DE，但我想知道这应该如何改变我输入文本的方式，因为文本字段将只显示整数值而不分组字符。 JSpinner 是个好主意——我一定会试试的。 【参考方案1】：好的，我成功了。解决方案远非简单，但至少它完全符合我的要求。除了返回双精度数而不是浮点数。一个主要限制是它不允许小数位数，但现在我可以接受。
import java.awt.BorderLayout;
import java.text.NumberFormat;
import java.text.ParseException;
import javax.swing.JComponent;
import javax.swing.JFormattedTextField;
import javax.swing.JSpinner;
import javax.swing.SpinnerNumberModel;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultFormatterFactory;
import javax.swing.text.DocumentFilter;
import javax.swing.text.NavigationFilter;
import javax.swing.text.NumberFormatter;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.Position.Bias;
public class JPercentField extends JComponent
private static final double MIN_VALUE = 0.0d;
private static final double MAX_VALUE = 1.0d;
private static final double STEP_SIZE = 0.01d;
private static final long serialVersionUID = -779235114254706347L;
private JSpinner spinner;
public JPercentField()
initComponents();
initLayout();
spinner.setValue(MIN_VALUE);
private void initComponents()
SpinnerNumberModel model = new SpinnerNumberModel(MIN_VALUE, MIN_VALUE, MAX_VALUE, STEP_SIZE);
spinner = new JSpinner(model);
initSpinnerTextField();
private void initSpinnerTextField()
DocumentFilter digitOnlyFilter = new PercentDocumentFilter(getMaximumDigits());
NavigationFilter navigationFilter = new BlockLastCharacterNavigationFilter(getTextField());
getTextField().setFormatterFactory(
new DefaultFormatterFactory(new PercentNumberFormatter(createPercentFormat(), navigationFilter,
digitOnlyFilter)));
getTextField().setColumns(6);
private int getMaximumDigits()
return Integer.toString((int) MAX_VALUE * 100).length();
private JFormattedTextField getTextField()
JSpinner.NumberEditor jsEditor = (JSpinner.NumberEditor) spinner.getEditor();
JFormattedTextField textField = jsEditor.getTextField();
return textField;
private NumberFormat createPercentFormat()
NumberFormat format = NumberFormat.getPercentInstance();
format.setGroupingUsed(false);
format.setMaximumIntegerDigits(getMaximumDigits());
format.setMaximumFractionDigits(0);
return format;
private void initLayout()
setLayout(new BorderLayout());
add(spinner, BorderLayout.CENTER);
public double getPercent()
return (Double) spinner.getValue();
public void setPercent(double percent)
spinner.setValue(percent);
private static class PercentNumberFormatter extends NumberFormatter
private static final long serialVersionUID = -1172071312046039349L;
private final NavigationFilter navigationFilter;
private final DocumentFilter digitOnlyFilter;
private PercentNumberFormatter(NumberFormat format, NavigationFilter navigationFilter,
DocumentFilter digitOnlyFilter)
super(format);
this.navigationFilter = navigationFilter;
this.digitOnlyFilter = digitOnlyFilter;
@Override
protected NavigationFilter getNavigationFilter()
return navigationFilter;
@Override
protected DocumentFilter getDocumentFilter()
return digitOnlyFilter;
@Override
public Class<?> getValueClass()
return Double.class;
@Override
public Object stringToValue(String text) throws ParseException
Double value = (Double) super.stringToValue(text);
return Math.max(MIN_VALUE, Math.min(MAX_VALUE, value));
/**
* NavigationFilter that avoids navigating beyond the percent sign.
*/
private static class BlockLastCharacterNavigationFilter extends NavigationFilter
private JFormattedTextField textField;
private BlockLastCharacterNavigationFilter(JFormattedTextField textField)
this.textField = textField;
@Override
public void setDot(FilterBypass fb, int dot, Bias bias)
super.setDot(fb, correctDot(fb, dot), bias);
@Override
public void moveDot(FilterBypass fb, int dot, Bias bias)
super.moveDot(fb, correctDot(fb, dot), bias);
private int correctDot(FilterBypass fb, int dot)
// Avoid selecting the percent sign
int lastDot = Math.max(0, textField.getText().length() - 1);
return dot > lastDot ? lastDot : dot;
private static class PercentDocumentFilter extends DocumentFilter
private int maxiumDigits;
public PercentDocumentFilter(int maxiumDigits)
super();
this.maxiumDigits = maxiumDigits;
@Override
public void insertString(FilterBypass fb, int offset, String text, AttributeSet attrs)
throws BadLocationException
// Mapping an insert as a replace without removing
replace(fb, offset, 0, text, attrs);
@Override
public void remove(FilterBypass fb, int offset, int length) throws BadLocationException
// Mapping a remove as a replace without inserting
replace(fb, offset, length, "", SimpleAttributeSet.EMPTY);
@Override
public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs)
throws BadLocationException
int replaceLength = correctReplaceLength(fb, offset, length);
String cleanInput = truncateInputString(fb, filterDigits(text), replaceLength);
super.replace(fb, offset, replaceLength, cleanInput, attrs);
/**
* Removes all non-digit characters
*/
private String filterDigits(String text) throws BadLocationException
StringBuilder sb = new StringBuilder(text);
for (int i = 0, n = sb.length(); i < n; i++)
if (!Character.isDigit(text.charAt(i)))
sb.deleteCharAt(i);
return sb.toString();
/**
* Removes all characters with which the resulting text would exceed the maximum number of digits
*/
private String truncateInputString(FilterBypass fb, String filterDigits, int replaceLength)
StringBuilder sb = new StringBuilder(filterDigits);
int currentTextLength = fb.getDocument().getLength() - replaceLength - 1;
for (int i = 0; i < sb.length() && currentTextLength + sb.length() > maxiumDigits; i++)
sb.deleteCharAt(i);
return sb.toString();
private int correctReplaceLength(FilterBypass fb, int offset, int length)
if (offset + length >= fb.getDocument().getLength())
// Don't delete the percent sign
return offset + length - fb.getDocument().getLength();
return length;
【讨论】：
【参考方案2】：1) 考虑使用JSpinner 而不是JFormattedTextField，因为您可以将SpinnerNumberModel 设置为初始值
来自 API
Integer value = new Integer(50);
Integer min = new Integer(0);
Integer max = new Integer(100);
Integer step = new Integer(1);
对于JSpinner（带有SpinnerNumberModel）的简单破解，它不允许另一个输入为数字，否则是否有可能输入Chars中的任何一个
2) 对于JFormattedTextField，您必须实施
对于JFormattedTextField 的这两种情况，如果值小于或大于所需范围，您必须为 catch 编写解决方法...
编辑：
.
.
完全不正确，:-) 你离......简单的错误:-)，你的结果有小错误，请看这段代码
import java.awt.BorderLayout;
import java.text.NumberFormat;
import javax.swing.*;
import javax.swing.text.*;
public class TestDigitsOnlySpinner
public static void main(String... args)
SwingUtilities.invokeLater(new Runnable()
public void run()
JFrame frame = new JFrame("enter digit");
JSpinner jspinner = makeDigitsOnlySpinnerUsingDocumentFilter();
frame.getContentPane().add(jspinner, BorderLayout.CENTER);
frame.getContentPane().add(new JButton("just another widget"), BorderLayout.SOUTH);
frame.pack();
frame.setVisible(true);
private JSpinner makeDigitsOnlySpinnerUsingDocumentFilter()
JSpinner spinner = new JSpinner(new SpinnerNumberModel());
JSpinner.NumberEditor jsEditor = (JSpinner.NumberEditor) spinner.getEditor();
JFormattedTextField textField = jsEditor.getTextField();
final DocumentFilter digitOnlyFilter = new DocumentFilter()
@Override
public void insertString(FilterBypass fb, int offset, String string, AttributeSet attr) throws BadLocationException
if (stringContainsOnlyDigits(string))
super.insertString(fb, offset, string, attr);
@Override
public void remove(FilterBypass fb, int offset, int length) throws BadLocationException
super.remove(fb, offset, length);
@Override
public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException
if (stringContainsOnlyDigits(text))
super.replace(fb, offset, length, text, attrs);
private boolean stringContainsOnlyDigits(String text)
for (int i = 0; i < text.length(); i++)
if (!Character.isDigit(text.charAt(i)))
return false;
return true;
;
/*NumberFormat format = NumberFormat.getIntegerInstance();
format.setGroupingUsed(false);// or add the group chars to the filter
NumberFormat format = NumberFormat.getInstance();*/
NumberFormat format = NumberFormat.getPercentInstance();
format.setGroupingUsed(false);
format.setGroupingUsed(true);// or add the group chars to the filter
format.setMaximumIntegerDigits(10);
format.setMaximumFractionDigits(2);
format.setMinimumFractionDigits(5);
textField.setFormatterFactory(new DefaultFormatterFactory(new InternationalFormatter(format)
private static final long serialVersionUID = 1L;
@Override
protected DocumentFilter getDocumentFilter()
return digitOnlyFilter;
));
return spinner;
);
【讨论】：
显然不可能获得一个行为与我在问题中描述的一样的组件。至少不是标准的 Swing 组件或一些简单的技巧。我现在使用的 JSpinner 范围为 0 - 100（如您所建议的），手动将值转换为浮点数并忽略不存在百分号。在嵌入式 JFormattedTextField 的 NumberFormatter 中将 allowInvalid 设置为 false 并将 overwriteMode 设置为 true ，行为就可以满足我的需要。 谢谢。但是，此代码仍然存在一些问题。当百分比或小数分隔符被删除时，没有办法让它们回来。两者都可以在 DocumentFilter 中通过更多的 if 来修复。对于这样一个简单的任务，付出了相当多的努力。 ;) @Roland 不知道...，请在此处发布（编辑您的帖子或作为新的答案，whatewer）显示您的问题的可运行代码，也许您犯了一些错误，或者也许我错过了什么...... 看看我的回答。谢谢你的帮助。 +1【参考方案3】：恕我直言https://docs.oracle.com/javase/tutorial/uiswing/components/formattedtextfield.html 给出了一个很好的例子（请参阅“指定格式化程序和使用格式化程序工厂”部分）。
关键是使用百分比格式来显示值和自定义 NumberFormatter 来编辑值。这种方法还允许使用小数位数。
// create a format for displaying percentages (with %-sign)
NumberFormat percentDisplayFormat = NumberFormat.getPercentInstance();
// create a format for editing percentages (without %-sign)
NumberFormat percentEditFormat = NumberFormat.getNumberInstance();
// create a formatter for editing percentages - input will be transformed to percentages (eg. 50 -> 0.5)
NumberFormatter percentEditFormatter = new NumberFormatter(percentEditFormat)
private static final long serialVersionUID = 1L;
@Override
public String valueToString(Object o) throws ParseException
Number number = (Number) o;
if (number != null)
double d = number.doubleValue() * 100.0;
number = new Double(d);
return super.valueToString(number);
@Override
public Object stringToValue(String s) throws ParseException
Number number = (Number) super.stringToValue(s);
if (number != null)
double d = number.doubleValue() / 100.0;
number = new Double(d);
return number;
;
// set allowed range
percentEditFormatter.setMinimum(0D);
percentEditFormatter.setMaximum(100D);
// create JFormattedTextField
JFormattedTextField field = new JFormattedTextField(
new DefaultFormatterFactory(
new NumberFormatter(percentDisplayFormat),
new NumberFormatter(percentDisplayFormat),
percentEditFormatter));
【讨论】：
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