How to give focus to nested component inside modal?

[wynme]

I am trying to have a modal component that contains an Input component.

However, I can't use the Input component when the modal component is triggered. I think this is because the Input component isn't focused on (but I could be wrong).

Here my code:

#include <ftxui/component/component.hpp>
#include <ftxui/component/component_options.hpp>
#include <ftxui/component/mouse.hpp>
#include <ftxui/component/screen_interactive.hpp>
#include <ftxui/dom/elements.hpp>

using namespace ftxui;


Component ModalComponent() {
    class Impl : public ComponentBase {
        Component input;
    public:
        explicit Impl(void) {
            input = Input("ABC");
        }

        Element OnRender(void) override {
            SetActiveChild(input); // Doesn't work
            return input->Render();
        }

        bool Focusable(void) const final {
            return true;
        }
    };

    return Make<Impl>();
}

int main(void) {
    auto screen = ScreenInteractive::TerminalOutput();

    bool show_modal = false;

    auto main_component = Checkbox("show modal?", &show_modal);
    auto modal_component = ModalComponent();
    modal_component |= CatchEvent([&](Event e) {
        if (e == Event::Character("q")) {
            show_modal = false;
            return true;
        }
        return false;
    });
    main_component |= Modal(modal_component, &show_modal);

    screen.Loop(main_component);
    return 0;
}

The Checkbox is the main component which can be used to trigger the modal component. The modal component is drawn, but the Input inside the modal component doesn't seem to function. The CatchEvent for the modal component works as expected.

Is there any way to make the Input inside the modal component work?

Thanks in advance!

[739C1AE2]

The issue is that your ModalComponent doesn't add the Input child component to the component tree. Add Add(input) in the constructor to fix it.

explicit Impl() {
    input = Input("ABC");
    Add(input);
}

[wynme]

It seems like I missed something while looking at examples. Thank you!