Java Swing JTextField - 只有数字
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Java Swing JTextField - Only Numbers
提问by Oliver Ni
I am making a small java Swing Applet that converts temperatures: TempConvert.java
我正在制作一个转换温度的小型 java Swing Applet：TempConvert.java
Here is my code:
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);
}
}
}
I want to restrict the JTextFielddegto only integers. Is there any way I can do that?
我想限制JTextFielddeg为只有整数。有什么办法可以做到吗？
Any help would be appreciated!
任何帮助，将不胜感激！
采纳答案by Neelam Sharma
You just need to convert your -
你只需要转换你的 -
JTextField deg;
to
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
This will return a general-purpose number format for the current default locale.
这将返回当前默认语言环境的通用数字格式。
Thanks
谢谢
回答by Paul Samsotha
"I want to restrict the JTextField deg to only integers."
“我想将 JTextField deg 限制为仅整数。”
Try this. Use a Document Filter
尝试这个。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);
}
});
回答by AbhishekJoshi
For a simple program like this, you can try to use Formatted Text Fields: http://docs.oracle.com/javase/tutorial/uiswing/components/formattedtextfield.html
对于这样的简单程序，您可以尝试使用格式化文本字段：http: //docs.oracle.com/javase/tutorial/uiswing/components/formattedtextfield.html
