JavaFX：适配器，ObjectProperty和双向绑定

Question

I want to understand how ObjectProperty works but still no luck. I have the following POJO:

public class Article{

    private LocalDateTime dateTime;

    private final PropertyChangeSupport propertyChangeSupport;

    public Article(String title) {
        this.propertyChangeSupport = new PropertyChangeSupport(this);
    }

    public LocalDateTime getDateTime() {
        return dateTime;
    }

    public void setDateTime(LocalDateTime dateTime) {
        LocalDateTime pv = this.dateTime;
        this.dateTime = dateTime;
        propertyChangeSupport.firePropertyChange("dateTime", pv, this.dateTime);
    }

    public void addPropertyChangeListener(PropertyChangeListener listener) {
        propertyChangeSupport.addPropertyChangeListener(listener);
    }

    public void removePropertyChangeListener(PropertyChangeListener listener) {
        propertyChangeSupport.removePropertyChangeListener(listener);
    }
} 

Now, I create objectProperty for dateTime field:

ObjectProperty<LocalDateTime> dateTimeProperty=new JavaBeanObjectPropertyBuilder().bean(article).name("dateTime").build();

And now I want to bind this dateTimeProperty to textField.textProperty(). And I have no idea how to do it: how will the data be formatted for showing dateTime in textField? How the instance of LocalDateTime will be created when I enter new date time in textField? We do have bidirectional binding. Please, explain.

Answer 1

Why not create your bean as a JavaFX Bean

public class Article {
    private ObjectProperty<LocalDateTime> dateTime = new SimpleObjectProperty<>();
    public final ObjectProperty<LocalDateTime> dateTimeProperty() {
         return dateTime;
    }
    public void setDateTime(LocalDateTime ldt) {
         dateTime.set(ldt);
    }
    public LocalDateTime getDateTime() {
         return dateTime.get();
    }
}

Then in your control you bind to the text control with a formatter

myTextField.textProperty().bindBidirectional(article.dateTimeProperty(), new LocalDateTimeStringConverter());

Answer 2

The best option is to use a TextFormatter on the text field:

// choose whatever formats you need here...
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy HH:mm:ss");
DateTimeFormatter parser = DateTimeFormatter.ofPattern("d/M/y H:m:s");

TextFormatter<LocalDateTime> textFormatter = new TextFormatter(new LocalDateTimeStringConverter(formatter, parser));
myTextField.setTextFormatter(textFormatter);

and then

textFormatter.valueProperty().bindBidirectional(dateTimeProperty);

If you want, you can also specify a filter on the TextFormatter , to limit editing to characters that only make sense in this context (though the details of that can get a bit tricky). Refer to the documentation for TextFormatter.Change for details.