Java 将内部具有FloatProperty的ObjectProperty绑定到其他属性

我有一篇

文章

类，里面有一些

属性

public class Article {
    private IntegerProperty id;
    private StringProperty name;
    private StringProperty description;
    private FloatProperty price;

    public Article(int id, String name, String description, float price) {
        this.id = new SimpleIntegerProperty(id);
        this.name = new SimpleStringProperty(name);
        this.description = new SimpleStringProperty(description);
        this.price = new SimpleFloatProperty(price);
    }

    ...
}

我有一个

Sale

类，它引用了一篇文章

public class Sale {
    private IntegerProperty id;
    private ObjectProperty<Article> article;
    private FloatProperty discount;
    private IntegerProperty quantity;
    private FloatProperty total;

    public Sale(int id, Article article, float discount, int quantity) {
        this.id = new SimpleIntegerProperty(id);
        this.article = new SimpleObjectProperty<>(article);
        this.discount = new SimpleFloatProperty(discount);
        this.quantity = new SimpleIntegerProperty(quantity);
        this.checked = new SimpleBooleanProperty(false);

        this.total = new SimpleFloatProperty();
        this.total.bind(Bindings.multiply(Bindings.subtract(this.article.get().priceProperty(), Bindings.multiply(this.article.get().priceProperty(), this.discount)), this.quantity));
    }

    public void setArticle(Article article) {
        this.article.set(article);
    }
    ...
}

我想我应该引用articleProperty而不是值，但我不知道如何引用。

您可以：

public Sale(int id, Article article, float discount, int quantity) {
    this.id = new SimpleIntegerProperty(id);
    this.article = new SimpleObjectProperty<>(article);
    this.discount = new SimpleFloatProperty(discount);
    this.quantity = new SimpleIntegerProperty(quantity);
    this.checked = new SimpleBooleanProperty(false);

    this.total = new SimpleFloatProperty();

    FloatProperty articlePriceProperty = new SimpleFloatProperty();
    if (this.article != null) {
        articlePriceProperty.bind(article.priceProperty());
    }
    this.article.addListener((obs, oldArticle, newArticle) -> {
        articlePriceProperty.unbind();
        if (newArticle == null) {
            articlePriceProperty.set(0);
        } else {
            articlePriceProperty.bind(newArticle.priceProperty());
        }
    });
    this.total.bind(Bindings.multiply(Bindings.subtract(articlePriceProperty, Bindings.multiply(articlePriceProperty(), this.discount)), this.quantity));
}

公开销售（整数id、物品、浮动折扣、整数数量）{
this.id=新的SimpleIntegerProperty（id）；
this.article=新的SimpleObject属性（article）；
this.discount=新的SimpleFloatProperty（折扣）；
this.quantity=新的SimpleIntegerProperty（数量）；
this.checked=新的SimpleBoleAnProperty（false）；
this.total=新的SimpleFloatProperty（）；
FloatProperty articlePriceProperty=新的SimpleFloatProperty（）；
if（this.article！=null）{
articlePriceProperty.bind（article.priceProperty（））；
}
this.article.addListener（（obs、oldArticle、newArticle）->{
articlePriceProperty.unbind（）；
if（newArticle==null）{
articlePriceProperty.set（0）；
}否则{
articlePriceProperty.bind（newArticle.priceProperty（））；
}
});
this.total.bind（Bindings.multiply（Bindings.subtract（articlePriceProperty，Bindings.multiply（articlePriceProperty（），this.discount）），this.quantity））；
}

您可以使用：

---

在减法中1d的含义是什么？您的总公式：

（价格-（价格*折扣））*数量

挖掘一个等价公式，避免在两个位置使用价格（使用分配规则）：

价格*数量*（1-折扣）

工作完美！谢谢：D（我只是讨厌

绑定。选择（…）

）

public Sale(int id, Article article, float discount, int quantity) {
    this.id = new SimpleIntegerProperty(id);
    this.article = new SimpleObjectProperty<>(article);
    this.discount = new SimpleFloatProperty(discount);
    this.quantity = new SimpleIntegerProperty(quantity);
    this.checked = new SimpleBooleanProperty(false);

    this.total = new SimpleFloatProperty();

    FloatProperty articlePriceProperty = new SimpleFloatProperty();
    if (this.article != null) {
        articlePriceProperty.bind(article.priceProperty());
    }
    this.article.addListener((obs, oldArticle, newArticle) -> {
        articlePriceProperty.unbind();
        if (newArticle == null) {
            articlePriceProperty.set(0);
        } else {
            articlePriceProperty.bind(newArticle.priceProperty());
        }
    });
    this.total.bind(Bindings.multiply(Bindings.subtract(articlePriceProperty, Bindings.multiply(articlePriceProperty(), this.discount)), this.quantity));
}

this.total.bind(Bindings.multiply(Bindings.selectFloat(this.article, "price")
                                          .multiply(this.quantity),
                                  Bindings.subtract(1d, this.discount)));