问题
EDIT - added at then end of the post the answer we were able to achieve
This is my first post in SO, so i hope i can ask everything right!
I searched and didn't quite find a answer to my question despite similar questions being posted, so i hope this isn't a repost.
This is what a i got, a small application that uses JTextField to receive user's input and on top of that i have a DocumentFilter so the user can only input integers and a period in order to receive values that represent weight.
My problem is, with my DocumentFilter I'm not being able to filter "copy pasted" text and i can't filter a selected text removal.
Here is the code for the Filter
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;
/**
* The Class IntAndDotFilter.
*/
public class IntAndDotFilter extends DocumentFilter {
/** The period counter. */
private int periodCounter = 0;
/** The number counter. */
private int numberCounter = 0;
private boolean canRemove = true;
public void setCanRemove(boolean canRemove) {
this.canRemove = canRemove;
}
@Override
public void replace(FilterBypass fb, int offset, int length, String text,
AttributeSet attrs) throws BadLocationException {
if (periodCounter == 0) { // If there is no . on the text
if (text.matches("\\.")) { // Checks if the input is a dot
super.replace(fb, offset, length,
text.replaceAll("[^0-9.]", ""), attrs);
periodCounter++; // If it is, inserts it and saves that info
} else {
super.replace(fb, offset, length,
text.replaceAll("[^0-9]", ""), attrs);
// If not, checks if the input is a digit
// and inserts if it is
}
} else { // If there is already a .
if (text.matches("\\.")) { // Checks if the input is another .
super.replace(fb, offset, length,
text.replaceAll("[^0-9]", ""), attrs);
// If it is, filters so that cannot be more than one .
} else {
if (text.matches("[0-9]")) { // Checks if it's a digit
if (numberCounter != 2) {
super.replace(fb, offset, length,
text.replaceAll("[^0-9]", ""), attrs);
numberCounter++;
// If yes, and if that is only the second one (0.00)
// inserts and
// saves the info that there are digits after the 1st .
// for removal purposes
} else {
super.replace(fb, offset, length,
text.replaceAll(".", ""), attrs);
// if it is the third+ digit after . , doesn't allow the
// input
}
} else {
super.replace(fb, offset, length, text.replaceAll(".", ""),
attrs);
// Not being a digit, doesn't allow the
// insertion of the given input
}
}
}
}
@Override
public void remove(FilterBypass fb, int offset, int length)
throws BadLocationException {
if (canRemove) {
if (periodCounter == 1) { // If there is a . in the text
if (numberCounter != 0) { // and If there are digits after the .
numberCounter--; // It means you'r removing a digit, so it
// saves
// that info
super.remove(fb, offset, length); // And removes it
} else { // If there are no digits it means you'r removing a .
periodCounter--; // It saves that info allowing a new . to
// be
// inserted
super.remove(fb, offset, length); // and removes it
}
} else { // If there is no . in the text there are no problems
super.remove(fb, offset, length); // so it just removes whatever
// there is (digit)
}
} else {
}
}
}
the insertString method does the same has the replace method so i left it out, but in the application it's implemented.
Thanks in advance for your time!
EDIT - Plus it now has a filter to restrain the height input too
public class IntAndDotFilter extends DocumentFilter {
/** The Constant _maxCharacters. */
private static final int _maxCharacters = 10;
/** The _is weight. */
private Boolean _isWeight = null;
public IntAndDotFilter(Boolean isWeight) {
super();
_isWeight = isWeight;
}
public void replace(FilterBypass fb, int offset, int length, String string,
AttributeSet attr) throws BadLocationException {
String text = fb.getDocument().getText(0, fb.getDocument().getLength());
text += string;
if (_isWeight) {
if ((fb.getDocument().getLength() + string.length() - length) <= _maxCharacters
&& text.matches("^[1]?[0-9]{1,2}([.][0-9]{0,2})?$")) {
super.replace(fb, offset, length, string, attr);
} else {
Toolkit.getDefaultToolkit().beep();
}
} else {
if ((fb.getDocument().getLength() + string.length() - length) <= _maxCharacters
&& text.matches("^([1]([.][0-9]{0,2})?)|([2]([.][0-5]?)?)$")) {
super.replace(fb, offset, length, string, attr);
} else {
Toolkit.getDefaultToolkit().beep();
}
}
}
@Override
public void remove(FilterBypass fb, int offset, int length)
throws BadLocationException {
String text = fb.getDocument().getText(0, fb.getDocument().getLength());
if (_isWeight) {
if (text.matches("^[1]?[0-9]{1,2}([.][0-9]{0,2})?$")) {
super.remove(fb, offset, length);
} else {
Toolkit.getDefaultToolkit().beep();
}
} else {
if (text.matches("^([1]([.][0-9]{0,2})?)|([2]([.][0-5]?)?)$")) {
super.remove(fb, offset, length);
} else {
Toolkit.getDefaultToolkit().beep();
}
}
}
回答1:
You're making the filtering more complicated than it has to be. For inserting (if the code is same is replace), you are not able to enter probably because of the \\. check. You will only be able to paste a period, as that's what you are checking for. As for the remove, the suggestion below will apply.
To simplify things, you should just get the entire text of the document, then use regex to check if the entire document string matches the regex. It's much simpler than what you are trying to do. You can get a good explanation of the filtering process here.
Here's an example, using just insertString and replace. For the remove, it's no different, just get the text, and check if it matches a regex. I took part of the example from the answer in the link above. The scenario was that the OP wanted max charcters, along with only one decimal place allowed. That's what the regex matches. But could also match anything as you're typing or inserting such as 00 00. 00.0
import java.awt.GridBagLayout;
import java.awt.Toolkit;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;
public class FilterDemo {
public FilterDemo() {
JFrame frame = new JFrame();
frame.setLayout(new GridBagLayout());
frame.setSize(300, 300);
frame.add(createFilteredField());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public JTextField createFilteredField() {
JTextField field = new JTextField();
AbstractDocument document = (AbstractDocument) field.getDocument();
final int maxCharacters = 10;
document.setDocumentFilter(new DocumentFilter() {
public void replace(FilterBypass fb, int offs, int length,
String str, AttributeSet a) throws BadLocationException {
String text = fb.getDocument().getText(0,
fb.getDocument().getLength());
text += str;
if ((fb.getDocument().getLength() + str.length() - length) <= maxCharacters
&& text.matches("^[0-9]+[.]?[0-9]{0,1}$")) {
super.replace(fb, offs, length, str, a);
} else {
Toolkit.getDefaultToolkit().beep();
}
}
public void insertString(FilterBypass fb, int offs, String str,
AttributeSet a) throws BadLocationException {
String text = fb.getDocument().getText(0,
fb.getDocument().getLength());
text += str;
if ((fb.getDocument().getLength() + str.length()) <= maxCharacters
&& text.matches("^[0-9]+[.]?[0-9]{0,1}$")) {
super.insertString(fb, offs, str, a);
} else {
Toolkit.getDefaultToolkit().beep();
}
}
});
return field;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new FilterDemo();
}
});
}
}
来源：https://stackoverflow.com/questions/24844559/jtextfield-using-document-filter-to-filter-integers-and-periods