如何在 JavaFX 中触发 Textfield 侦听器？

Question

In Java, I'm trying to fire a Textfield listener.

The only solution I've found is to use setText with a space:

txt.setText(" "); 

What is the correct way to do it?

Details:

TextField txt = new TextField();
        txt.setPromptText("Search");
        txt.textProperty().addListener(new ChangeListener() {
            public void changed(ObservableValue observable, Object oldVal,Object newVal) {
               //...to do
            }
        };
txt.setText(" "); //Firing the listener

Answer 1

Invoking a stored listener reference

You could record a reference to the listener and invoke that whenever you want, for example:

TextField txt = new TextField();
txt.setPromptText("Search");

ChangeListener<String> txtListener =
        (observable, oldValue, newValue) ->
                System.out.println(
                        "Search text updated to: " + newValue
                );

txt.textProperty().addListener(
        txtListener
);

txtListener.changed(
        txt.textProperty(),
        null,
        "frobozz"
);

This will output " Search text updated to: frobozz ". What I don't much like about this is that it doesn't carry a lot of semantic meaning and the text hasn't really changed.

Alternate approach

An alternate approach is to have a function which is named related to your application and invoke that whenever you want either inside or outside the listener. I prefer this alternate approach.

txt.textProperty().addListener(
        (observable, oldValue, newValue) -> search(newValue)
);
search(null);

. . .

private void search(String searchText) {
    System.out.println(
            "Search result for: " + searchText
    );
}

This will output: " Search result for: null ".

Note: this answer used Java 8 code .