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How would one go about scrollable table? about ftxui HOT 2 CLOSED

bqle commented on June 8, 2024

How would one go about scrollable table?

from ftxui.

Comments (2)

ArthurSonzogni commented on June 8, 2024

Hi @bqle!

I spotted several issues with the current code, and then provided an example based on yours.

Error 1

    bool OnEvent(Event event) final {
      return true;
    }

Don't handle every events (e.g. returning true)!. This prevents the parent component: Container::Vertical() to handle the up/down keys.

Error 2

    Element Render() final {
      return hbox({
          text("Hello!")
      });
    }

You should use the active and select element to decorate the currently Active() or Focused() component. This is what will cause the frame element to position the active element in the center of the scrolled area.

Error 3

    bool Focusable() const final { return true; }

This should be used to indicate the parent element not to skip it when pressing up/down.

Fixed code:

#include <memory>  // for allocator, __shared_ptr_access, shared_ptr
#include <string>  // for to_string, operator+

#include "ftxui/component/captured_mouse.hpp"  // for ftxui
#include "ftxui/component/component.hpp"       // for Button, Renderer, Vertical
#include "ftxui/component/component_base.hpp"  // for ComponentBase
#include "ftxui/component/component_options.hpp"   // for ButtonOption
#include "ftxui/component/screen_interactive.hpp"  // for ScreenInteractive
#include "ftxui/dom/elements.hpp"  // for operator|, text, Element, hbox, separator, size, vbox, border, frame, vscroll_indicator, HEIGHT, LESS_THAN
#include "ftxui/dom/table.hpp"     // for Table
#include "ftxui/screen/color.hpp"  // for Color, Color::Default, Color::GrayDark, Color::White

using namespace ftxui;

Component MakeOne() {
  class Impl : public ComponentBase {
    Element Render() final {
      const bool active = Active();
      const bool focused = Focused();
      auto focus_management = focused  ? ftxui::focus
                              : active ? ftxui::select
                                       : ftxui::nothing;
      auto style = focused ? bold : nothing;
      return text("Hello") | style | focus_management;
    }

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

  return Make<Impl>();
}

int main() {
  auto container = Container::Vertical({});
  for (int i = 0; i < 30; i++) {
    container->Add(MakeOne());
  }

  auto screen = ScreenInteractive::FitComponent();

  auto renderer = Renderer(container, [&] {
    return vbox({
               container->Render() | vscroll_indicator | frame |
                   size(HEIGHT, LESS_THAN, 20),
           }) |
           border;
  });

  auto component = CatchEvent(renderer, [&](Event event) {
    if (event == Event::Character('q')) {
      screen.ExitLoopClosure()();
      return true;
    }
    return false;
  });

  screen.Loop(renderer);

  return 0;
}