How to pass number to TextField JavaFX?

Question

I am working on simple calculator, where users input two numbers in TextField and the result is displayed in result TextField. I used Double.pars

Answer 1

setText expects a String as parameter. You need to convert the result to a String, e.g. by using Double.toString.

However in this case I recommend adding a TextFormatter to the TextField which allows you to assign/input values of a type different to String using a TextField:

TextField summand1 = new TextField();
TextField summand2 = new TextField();
TextField result = new TextField();

StringConverter converter = new DoubleStringConverter();

TextFormatter tf1 = new TextFormatter<>(converter, 0d);
TextFormatter tf2 = new TextFormatter<>(converter, 0d);
TextFormatter tfRes = new TextFormatter<>(converter, 0d);

summand1.setTextFormatter(tf1);
summand2.setTextFormatter(tf2);
result.setTextFormatter(tfRes);

tfRes.valueProperty().bind(
        Bindings.createObjectBinding(() -> tf1.getValue() + tf2.getValue(),
                tf1.valueProperty(),
                tf2.valueProperty()));

result.setEditable(false);

This allows you to assign the value using the TextFormatter, e.g.

double someValue = 3d;
tf1.setValue(someValue);