将TextField绑定到ReadOnlyDoubleProperty

问题描述

我可以将TextField的text属性绑定到DoubleProperty，如下所示:

I can bind a TextField's text property to a DoubleProperty, like this:

textField.textProperty().bindBidirectional(someDoubleProperty, new NumberStringConverter());

但是如果我的someDoubleProperty是ReadOnlyDoubleProperty的实例而不是DoubleProperty怎么办?

But what if my someDoubleProperty is an instance of ReadOnlyDoubleProperty instead of DoubleProperty?

我对双向绑定完全不感兴趣.我之所以使用这种方法，是因为没有这样的东西

I am acutally not interested in a bidirectional binding. I use this method only because there is no such thing as

textField.textProperty().bind(someDoubleProperty, new NumberStringConverter());

我是否需要使用侦听器，或者是否有绑定解决方案"?

Do I need to use listeners instead or is there a "binding-solution" for that as well?

有东西吗

textField.textProperty().bind(someDoubleProperty, new NumberStringConverter());

在那里?

推荐答案

对于单向绑定，您可以执行以下操作:

For a unidirectional binding, you can do:

textField.textProperty().bind(Bindings.createStringBinding(
    () -> Double.toString(someDoubleProperty.get()),
    someDoubleProperty));

第一个参数是生成所需字符串的函数.如果需要，您可以在此处使用自己选择的格式化程序.

The first argument is a function generating the string you want. You could use a formatter of your choosing there if you wanted.

第二个(和任何后续的)参数是要绑定的属性；也就是说，如果这些属性中的任何一个发生了更改，则绑定将无效(即需要重新计算).

The second (and any subsequent) argument(s) are properties to which to bind; i.e. if any of those properties change, the binding will be invalidated (i.e. needs to be recomputed).

等效地，您可以

textField.textProperty().bind(new StringBinding() {
    {
        bind(someDoubleProperty);
    }

    @Override
    protected String computeValue() {
        return Double.toString(someDoubleProperty.get());
    }
});

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