What is the recommended way to make a numeric Text

Question

I need to restrict input into a TextField to integers. Any advice?

Answer 1

Update 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:

• 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.

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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 (maxValue < minValue) 
      throw new IllegalArgumentException(
        "IntField max value " + minValue + " less than min 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 (!"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)) {
          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()));
      }
    });
  }
}

Answer 2

TextField text = new TextField();

text.textProperty().addListener(new ChangeListener<String>() {
    @Override
    public void changed(ObservableValue<? extends String> observable,
            String oldValue, String newValue) {
        try {
            Integer.parseInt(newValue);
            if (newValue.endsWith("f") || newValue.endsWith("d")) {
                manualPriceInput.setText(newValue.substring(0, newValue.length()-1));
            }
        } catch (ParseException e) {
            text.setText(oldValue);
        }
    }
});

The if clause is important to handle inputs like 0.5d or 0.7f which are correctly parsed by Int.parseInt(), but shouldn't appear in the text field.

Answer 3

This code works fine for me even if you try to copy/paste.

myTextField.textProperty().addListener((observable, oldValue, newValue) -> {
    if (!newValue.matches("\\d*")) {
        myTextField.setText(oldValue);

    }
});

Answer 4

this Code Make your textField Accept only Number

textField.lengthProperty().addListener((observable, oldValue, newValue) -> {
        if(newValue.intValue() > oldValue.intValue()){
            char c = textField.getText().charAt(oldValue.intValue());
            /** Check if the new character is the number or other's */
            if( c > '9' || c < '0'){
                /** if it's not number then just setText to previous one */
                textField.setText(textField.getText().substring(0,textField.getText().length()-1));
            }
        }
    });

Answer 5

In recent updates of JavaFX, you have to set new text in Platform.runLater method just like this:

    private void set_normal_number(TextField textField, String oldValue, String newValue) {
    try {
        int p = textField.getCaretPosition();
        if (!newValue.matches("\\d*")) {
            Platform.runLater(() -> {
                textField.setText(newValue.replaceAll("[^\\d]", ""));
                textField.positionCaret(p);
            });
        }
    } catch (Exception e) {
    }
}

It's a good idea to set caret position too.

Answer 6

I don't like exceptions thus I used the matches function from String-Class

text.textProperty().addListener(new ChangeListener<String>() {
    @Override
    public void changed(ObservableValue<? extends String> observable, String oldValue, 
        String newValue) {
        if (newValue.matches("\\d*")) {
            int value = Integer.parseInt(newValue);
        } else {
            text.setText(oldValue);
        }
    }
});