JavaFX Spinner empty text nullpointerexception

Question

I have an issue where an editable JavaFX 8 Spinner causes an uncaught NullPointerException if one clears the editor text and commits and then click

Answer 1

I would consider this a bug: the IntegerSpinnerValueFactory should properly handle this case.

One workaround is to provide a converter to the spinner value factory that evaluates to a default value if the text value is not valid:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Spinner;
import javafx.scene.control.SpinnerValueFactory.IntegerSpinnerValueFactory;
import javafx.stage.Stage;
import javafx.util.StringConverter;

public class Test extends Application {
    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage aPrimaryStage) throws Exception {
        IntegerSpinnerValueFactory valueFactory = new IntegerSpinnerValueFactory(0, 10);

        valueFactory.setConverter(new StringConverter() {

            @Override
            public String toString(Integer object) {
                return object.toString() ;
            }

            @Override
            public Integer fromString(String string) {
                if (string.matches("-?\\d+")) {
                    return new Integer(string);
                }
                // default to 0:
                return 0 ;
            }

        });

        Spinner spinner = new Spinner<>(valueFactory);
        spinner.setEditable(true);
        aPrimaryStage.setScene(new Scene(spinner));
        aPrimaryStage.show();
    }
}