Java/JavaFX slider 小数点

Question

I'm a new JavaFX programmer and my question is I'm getting multiple decimal points in the slider and I only want one. I'm getting like 99.99999999999 for each value within but I would love to get only one like 99.9

The thing is printf is not applicable here I guess and I only know that way >.<

private void createView() {

        final GridPane radioGridPane = new GridPane();
        final Label frequencyLabel = new Label("something");
        final Slider sliderFrequency = new Slider(87.9, 107.9, 90);

        frequencyLabel.textProperty().bind(sliderFrequency.valueProperty().asString());
        radioGridPane.add(frequencyLabel, 2, 1);
        radioGridPane.add(sliderFrequency, 3, 1);

        this.setCenter(radioGridPane);
        radioGridPane.setGridLinesVisible(true);
    }

Answer 1

You were actually quite close. You can use asString method with the following signature: javafx.beans.binding.NumberExpressionBase#asString(java.lang.String) that accepts a format parameter.

Example usage:

public class FormatBindingSSCCE extends Application {

    @Override
    public void start(Stage stage) {
        final Label frequencyLabel = new Label();
        final Slider sliderFrequency = new Slider(87.9, 107.9, 90);
        frequencyLabel.textProperty().bind(sliderFrequency.valueProperty().asString("%.1f"));
        
        final GridPane radioGridPane = new GridPane();
        radioGridPane.add(frequencyLabel, 2, 1);
        radioGridPane.add(sliderFrequency, 3, 1);

        final Scene scene = new Scene(radioGridPane);
        stage.setScene(scene);
        stage.show();
    }

}

Answer 2

You can multiply the decimal value by 10, truncate/floor it to an integer and then divide it by 10 again. That will give you the value with a single decimal after the point. Code:

float val = 0.999f;
float valOneDecimal = ((int) (val * 10f)) / 10f;