问题描述
-
在我的Java表单中有一个
jtextfield
.我不想输入alpha(字符),只允许输入数字.
Have a
jtextfield
in my java form. I want to not allow to type alpha(Characters) and only allow to type numbers.
并且不能键入2个小数点和小数点后两个数字.(以jtextfield
为价格.)
And can't type 2 decimal point and two numbers after the decimal point.(that jtextfield
for price..)
请告诉我如何逐步进行操作.
Please tell me how to do this step by step.
推荐答案
-
将JFormattedTextField与NumberFormatter一起使用
use JFormattedTextField with NumberFormatter
-
限制小数位数
restrict number of decimal places
设置各种取整模式
限制范围,设置最小值和/或最大值
restrict range, set minimal and/or maximal value
另一种方法是将JSpinner与SPinnerNUmberModel一起使用,但必须使用DocumentFilter
another of ways is to use JSpinner with SPinnerNUmberModel, but required to use DocumentFilter
例如
import java.awt.*;
import java.awt.font.TextAttribute;
import java.math.*;
import java.text.*;
import java.util.Map;
import javax.swing.*;
import javax.swing.JFormattedTextField.*;
import javax.swing.event.*;
import javax.swing.text.InternationalFormatter;
public class DocumentListenerAdapter {
public DocumentListenerAdapter() {
JFrame frame = new JFrame("AbstractTextField Test");
final JFormattedTextField textField1 = new JFormattedTextField(new Float(10.01));
textField1.setFormatterFactory(new AbstractFormatterFactory() {
@Override
public AbstractFormatter getFormatter(JFormattedTextField tf) {
NumberFormat format = DecimalFormat.getInstance();
format.setMinimumFractionDigits(2);
format.setMaximumFractionDigits(2);
format.setRoundingMode(RoundingMode.HALF_UP);
InternationalFormatter formatter = new InternationalFormatter(format);
formatter.setAllowsInvalid(false);
//formatter.setMinimum(0.0);
//formatter.setMaximum(1000.00);
return formatter;
}
});
final Map attributes = (new Font("Serif", Font.BOLD, 16)).getAttributes();
attributes.put(TextAttribute.STRIKETHROUGH, TextAttribute.STRIKETHROUGH_ON);
final JFormattedTextField textField2 = new JFormattedTextField(new Float(10.01));
textField2.setFormatterFactory(new AbstractFormatterFactory() {
@Override
public AbstractFormatter getFormatter(JFormattedTextField tf) {
NumberFormat format = DecimalFormat.getInstance();
format.setMinimumFractionDigits(2);
format.setMaximumFractionDigits(2);
format.setRoundingMode(RoundingMode.HALF_UP);
InternationalFormatter formatter = new InternationalFormatter(format);
formatter.setAllowsInvalid(false);
//formatter.setMinimum(0.0);
//formatter.setMaximum(1000.00);
return formatter;
}
});
textField2.getDocument().addDocumentListener(new DocumentListener() {
@Override
public void changedUpdate(DocumentEvent documentEvent) {
printIt(documentEvent);
}
@Override
public void insertUpdate(DocumentEvent documentEvent) {
printIt(documentEvent);
}
@Override
public void removeUpdate(DocumentEvent documentEvent) {
printIt(documentEvent);
}
private void printIt(DocumentEvent documentEvent) {
DocumentEvent.EventType type = documentEvent.getType();
double t1a1 = (((Number) textField2.getValue()).doubleValue());
if (t1a1 > 1000) {
Runnable doRun = new Runnable() {
@Override
public void run() {
textField2.setFont(new Font(attributes));
textField2.setForeground(Color.red);
}
};
SwingUtilities.invokeLater(doRun);
} else {
Runnable doRun = new Runnable() {
@Override
public void run() {
textField2.setFont(new Font("Serif", Font.BOLD, 16));
textField2.setForeground(Color.black);
}
};
SwingUtilities.invokeLater(doRun);
}
}
});
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(textField1, BorderLayout.NORTH);
frame.add(textField2, BorderLayout.SOUTH);
frame.setVisible(true);
frame.pack();
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
DocumentListenerAdapter main = new DocumentListenerAdapter();
}
});
}
}
这篇关于Java中的jtextfield上仅允许数字和一个小数点的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!