CODEWITHSUNDEEP
javajavafxtreeview
tw-S
tw-S

Reputation: 1217

BeforeTreeItemSelectionChanged event in JavaFX TreeView?

In JavaFX TreeView, is there an event similar to "BeforeTreeItemSelectionChanged"? I would like to save some settings on the old TreeItem before a new TreeItem is clicked. Thanks.

Upvotes: 1

Views: 120

Answers (1)

DVarga
DVarga

Reputation: 21799

If you just want to have a reference to the previously selected item you can add a ChangeListener to listen to the change of the selectedItemProperty of the selection model of the TreeView as it's changed method passes the previous value for you:

changed(ObservableValue<? extends T> observable, T oldValue, T newValue)

This example prints the value of the previously selected item on selection:

treeView.getSelectionModel().selectedItemProperty().addListener((obs, oldVal, newVal) -> {
    if(oldVal != null)
        System.out.println(oldVal.getValue());
});

And this is the same, but using anonymous class to see the types:

treeView.getSelectionModel().selectedItemProperty().addListener(new ChangeListener<TreeItem<String>>() {
    @Override
    public void changed(ObservableValue<? extends TreeItem<String>> observable, TreeItem<String> oldValue, TreeItem<String> newValue) {
        if(oldValue != null)
            System.out.println(oldValue.getValue());
    }
});

Upvotes: 3

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