JavaFX Treeview返回选定项

Question

注意：我实际上不确定为什么这种情况首先需要监听器，因为我甚至不想经常监听，而是在调用方法时得到结果。

    private CampaignObject getLeadSelect(){
    CampaignObject co = null;

    campTree.getSelectionModel().selectedItemProperty().addListener(
        new ChangeListener<TreeItem <CampaignObject>>() {
            @Override
            public void changed(ObservableValue<? extends TreeItem<CampaignObject>> observableValue, 
                    TreeItem<CampaignObject> oldItem, TreeItem<CampaignObject> newItem) {
                    co = newItem.getValue());
        }
    });

    return co;
}

Answer 1

如果不需要监听器，就不要定义监听器。听起来你只是需要

private CampaignObject getLeadSelect(){
    TreeItem<CampaignObject> selectedItem = campTree.getSelectionModel().getSelectedItem();
    return selectedItem == null ? null : selectedItem.getValue() ;
}

如果启用了多个选择，并且需要选定的模型对象列表，请执行

private List<CampaignObject> getAllSelected() {
    return campTree.getSelectionModel().getSelectedItems()
           .stream()
           .map(TreeItem::getValue)
           .collect(Collectors.toList());
}

如果希望将选定的项作为模型对象进行观察，可以执行如下操作：

ObjectProperty<CampaignObject> selectedCampaign = new SimpleObjectProperty<>();
selectedCampaign.bind(Bindings.createObjectBinding(() -> {
    TreeItem<CampaignObject> selectedItem = campTree.getSelectionModel().getSelectedItem();
    return selectedItem == null ?  null : selectedItem.getValue();
}, campTree.getSelectionModel().selectedItemProperty()));

selectedCampaign.addListener((obs, oldCampaign, newCampaign) -> {
    // ...
});