javafx Bindings.createStringBinding 但绑定(bind)实际上不起作用

Question

我正在尝试借助 Bindings 将 Label 的 textProperty 绑定(bind)到对象的 SimpleIntegerProperty但是当我实时更改对象的 SimpleIntegerProperty 时，它不会更改文本。对于如何更改 textProperty 的任何帮助，我们将不胜感激。

package sample;

import javafx.beans.binding.Bindings;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;
import javafx.scene.control.Slider;

import java.net.URL;
import java.util.ResourceBundle;

public class Controller implements Initializable
{

    @FXML
    private Slider slider;

    @FXML
    private Label label;

    @Override
    public void initialize(URL location, ResourceBundle resources) {

        MyObject object = new MyObject(0);

        label.textProperty().bind(Bindings.createStringBinding(() -> " hello " + object.numberProperty().get() * (10 + 12)/2));

        object.numberProperty().bind(slider.valueProperty());

    }
}


class MyObject {

    private SimpleIntegerProperty number;

    public Object(int number){
        this.number = new SimpleIntegerProperty(number);
    }

    public SimpleIntegerProperty numberProperty(){return this.number;}
}    

Answer 1

您需要“告诉”Bindings，哪些Observable要观察变化。此可变参数是 createStringBinding 方法的第二个参数。在这种情况下，您只需传递一个 Observable:object.numberProperty()

label.textProperty().bind(
   Bindings.createStringBinding(
      () -> " hello " + object.numberProperty().get() * (10 + 12)/2,
      object.numberProperty()));