防止制表符切换

Question

我用Vaadin23。

是否有合法的方法来防止标签切换？据我所知，文档方法

public Registration addSelectedChangeListener(
            ComponentEventListener<SelectedChangeEvent> listener) {
        return addListener(SelectedChangeEvent.class, listener);
    }

注册监听器，它是在选项卡更改事件之后触发的。

有什么选择吗？

谢谢!

Answer 1

如果选项卡内容是导航目标(路由)，则可以在窗体视图中使用BeforeLeaveObserver接口：

public class SignupForm extends Div
        implements BeforeLeaveObserver {
    @Override
    public void beforeLeave(BeforeLeaveEvent event) {
        if (hasChanges()) {
            ContinueNavigationAction action =
                    event.postpone();
            ConfirmDialog confirmDialog = new ConfirmDialog();
                 confirmDialog.setText("Your form has changes! Are you sure you want to leave?");
                 confirmDialog.setCancelable(true);
                 confirmDialog.addConfirmListener(__ -> action.proceed());
                 confirmDialog.open();
        }
    }

    private boolean hasChanges() {
        // TODO: implement your logic to check if there are unsaved changes
    }
}