What is the recommended way to make a numeric TextField in JavaFX?
Very old thread, but this seems neater and strips out non-numeric characters if pasted.
// force the field to be numeric only
textField.textProperty().addListener(new ChangeListener<String>() {
@Override
public void changed(ObservableValue<? extends String> observable, String oldValue,
String newValue) {
if (!newValue.matches("\\d*")) {
textField.setText(newValue.replaceAll("[^\\d]", ""));
}
}
});
javafx.scene.control.TextFormatter
Updated Apr 2016
This answer was created some years ago and the original answer is largely obsolete now.
Since Java 8u40, Java has a TextFormatter which is usually best for enforcing input of specific formats such as numerics on JavaFX TextFields:
- Numeric TextField for Integers in JavaFX 8 with TextFormatter and/or UnaryOperator
- Java 8 U40 TextFormatter (JavaFX) to restrict user input only for decimal number
- String with numbers and letters to double javafx
See also other answers to this question which specifically mention TextFormatter.
Original Answer
There are some examples of this in this gist, I have duplicated one of the examples below:
// helper text field subclass which restricts text input to a given range of natural int numbers
// and exposes the current numeric int value of the edit box as a value property.
class IntField extends TextField {
final private IntegerProperty value;
final private int minValue;
final private int maxValue;
// expose an integer value property for the text field.
public int getValue() { return value.getValue(); }
public void setValue(int newValue) { value.setValue(newValue); }
public IntegerProperty valueProperty() { return value; }
IntField(int minValue, int maxValue, int initialValue) {
if (minValue > maxValue)
throw new IllegalArgumentException(
"IntField min value " + minValue + " greater than max value " + maxValue
);
if (!((minValue <= initialValue) && (initialValue <= maxValue)))
throw new IllegalArgumentException(
"IntField initialValue " + initialValue + " not between " + minValue + " and " + maxValue
);
// initialize the field values.
this.minValue = minValue;
this.maxValue = maxValue;
value = new SimpleIntegerProperty(initialValue);
setText(initialValue + "");
final IntField intField = this;
// make sure the value property is clamped to the required range
// and update the field's text to be in sync with the value.
value.addListener(new ChangeListener<Number>() {
@Override public void changed(ObservableValue<? extends Number> observableValue, Number oldValue, Number newValue) {
if (newValue == null) {
intField.setText("");
} else {
if (newValue.intValue() < intField.minValue) {
value.setValue(intField.minValue);
return;
}
if (newValue.intValue() > intField.maxValue) {
value.setValue(intField.maxValue);
return;
}
if (newValue.intValue() == 0 && (textProperty().get() == null || "".equals(textProperty().get()))) {
// no action required, text property is already blank, we don't need to set it to 0.
} else {
intField.setText(newValue.toString());
}
}
}
});
// restrict key input to numerals.
this.addEventFilter(KeyEvent.KEY_TYPED, new EventHandler<KeyEvent>() {
@Override public void handle(KeyEvent keyEvent) {
if(intField.minValue<0) {
if (!"-0123456789".contains(keyEvent.getCharacter())) {
keyEvent.consume();
}
}
else {
if (!"0123456789".contains(keyEvent.getCharacter())) {
keyEvent.consume();
}
}
}
});
// ensure any entered values lie inside the required range.
this.textProperty().addListener(new ChangeListener<String>() {
@Override public void changed(ObservableValue<? extends String> observableValue, String oldValue, String newValue) {
if (newValue == null || "".equals(newValue) || (intField.minValue<0 && "-".equals(newValue))) {
value.setValue(0);
return;
}
final int intValue = Integer.parseInt(newValue);
if (intField.minValue > intValue || intValue > intField.maxValue) {
textProperty().setValue(oldValue);
}
value.set(Integer.parseInt(textProperty().get()));
}
});
}
}
I know this is a rather old thread, but for future readers here is another solution I found quite intuitive:
public class NumberTextField extends TextField
{
@Override
public void replaceText(int start, int end, String text)
{
if (validate(text))
{
super.replaceText(start, end, text);
}
}
@Override
public void replaceSelection(String text)
{
if (validate(text))
{
super.replaceSelection(text);
}
}
private boolean validate(String text)
{
return text.matches("[0-9]*");
}
}
Edit: Thanks none_ and SCBoy for your suggested improvements.