HOWTO · Java
How to Format Text Field Number Format in JavaFX
This tutorial demonstrates how to create a number format text field in JavaFX.
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The TextFormatter class is used to create fields with certain formats. It can also be used to create a numeric text field in JavaFX.
This tutorial demonstrates how to create a numeric text field in JavaFX.
JavaFX Text Field Number Format
JavaFX.scene.control.TextFormatter<V> is used to create fields with certain formats. The Formatter describes a format TextInputControl text with two different structures.
One is a filter getFilter() to modify the user input, and the other is a value converter getValueConverter() used to provide a special format that represents a value of type V. The TextFormatter can be created with just the filter and value converter.
The syntax for TextFormatter is:
TextFormatter<Integer> Text_Formatter = new TextFormatter<Integer>(String_Converter, 0, Integer_Filter);
Numeric_Field.setTextFormatter(Text_Formatter);
The TextFormatter can be an integer or any other type, and the setTextFormatter method is used to apply the TextFormatter to the field.
Let’s try an example to create a numeric text field:
package delftstack;
import java.util.function.UnaryOperator;
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.control.TextFormatter;
import javafx.scene.control.TextFormatter.Change;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.StringConverter;
import javafx.util.converter.IntegerStringConverter;
public class Numeric_TextField extends Application {
@Override
public void start(Stage Demo_Stage) {
TextField Numeric_Field = new TextField();
UnaryOperator<Change> Integer_Filter = change -> {
String Demo_Text = change.getControlNewText();
if (Demo_Text.matches("-?([1-9][0-9]*)?")) {
return change;
} else if ("-".equals(change.getText())) {
if (change.getControlText().startsWith("-")) {
change.setText("");
change.setRange(0, 1);
change.setCaretPosition(change.getCaretPosition() - 2);
change.setAnchor(change.getAnchor() - 2);
return change;
} else {
change.setRange(0, 0);
return change;
}
}
return null;
};
StringConverter<Integer> String_Converter = new IntegerStringConverter() {
@Override
public Integer fromString(String s) {
if (s.isEmpty())
return 0;
return super.fromString(s);
}
};
TextFormatter<Integer> Text_Formatter =
new TextFormatter<Integer>(String_Converter, 0, Integer_Filter);
Numeric_Field.setTextFormatter(Text_Formatter);
// demo listener:
Text_Formatter.valueProperty().addListener(
(obs, oldValue, newValue) -> System.out.println(newValue));
VBox VBox_Root = new VBox(5, Numeric_Field, new Button("Click Here"));
VBox_Root.setAlignment(Pos.CENTER);
Scene scene = new Scene(VBox_Root, 300, 120);
Demo_Stage.setScene(scene);
Demo_Stage.show();
}
public static void main(String[] args) {
launch(args);
}
}
The code above uses a UnaryOperator for the filter and StringConverter as a value. The code uses TextFormatter to create a text field that will only take the integer values.
See output:
