FocusZoneViewManager.cpp

// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.

#include "pch.h"

#include "FocusZoneViewManager.h"

#include "ViewControl.h"

#include "DynamicAutomationProperties.h"

#include <Modules/NativeUIManager.h>
#include <Utils/AccessibilityUtils.h>
#include <Utils/PropertyUtils.h>

#include <INativeUIManager.h>
#include <IReactInstance.h>

#include <winrt/Windows.System.h>
#include <winrt/Windows.UI.Core.h>
#include <winrt/Windows.UI.Xaml.Input.h>
#include <winrt/Windows.UI.Xaml.Controls.Primitives.h>

namespace winrt {
using namespace Windows::Foundation;
using namespace Windows::UI;
using namespace Windows::UI::Xaml;
using namespace Windows::UI::Xaml::Controls;
using namespace Windows::UI::Xaml::Controls::Primitives;
using namespace Windows::UI::Xaml::Media;
} // namespace winrt

namespace react {
namespace uwp {

FocusZoneViewManager::FocusZoneViewManager(const std::shared_ptr<IReactInstance> &reactInstance) : Super(reactInstance) {}

const char *FocusZoneViewManager::GetName() const {
  return "FocusZoneView";
}

XamlView FocusZoneViewManager::CreateViewCore(int64_t /*tag*/) {
  auto panel = winrt::make<winrt::react::uwp::implementation::ViewPanel>();
  panel.VerticalAlignment(winrt::VerticalAlignment::Stretch);
  panel.HorizontalAlignment(winrt::HorizontalAlignment::Stretch);

  m_panelKeyDownRevoker = panel.KeyDown(winrt::auto_revoke, [=](const winrt::IInspectable &sender, const winrt::KeyRoutedEventArgs &e) {
    OnKeyDown(sender, e);
  });
  return panel.as<XamlView>();
}

void FocusZoneViewManager::OnKeyDown(const winrt::IInspectable &sender, const winrt::KeyRoutedEventArgs &e) {
  winrt::XamlRoot xamlRoot = nullptr;
  auto wkinstance = GetReactInstance();
  if (auto instance = wkinstance.lock()) {
    xamlRoot = static_cast<NativeUIManager *>(instance->NativeUIManager())->tryGetXamlRoot();
  }
  if (!xamlRoot) {
    return;
  }

  auto senderFrameworkElement = sender.try_as<winrt::FrameworkElement>();
  auto focusedElement = winrt::FocusManager::GetFocusedElement(xamlRoot).try_as<winrt::DependencyObject>();
  winrt::FindNextElementOptions findNextElementOptions = winrt::FindNextElementOptions();
  findNextElementOptions.SearchRoot(xamlRoot.Content());

  if (e.Key() == winrt::Windows::System::VirtualKey::Up) {
    auto firstFocusableElement =
        winrt::FocusManager::FindFirstFocusableElement(senderFrameworkElement).try_as<winrt::DependencyObject>();
    auto isFirstElementFocused = firstFocusableElement == focusedElement;
    if (!isFirstElementFocused)
    {
      winrt::FocusManager::TryMoveFocus(winrt::FocusNavigationDirection::Previous, findNextElementOptions);
      e.Handled(true);
    }
  } else if (e.Key() == winrt::Windows::System::VirtualKey::Down) {
    auto lastFocusableElement = winrt::FocusManager::FindLastFocusableElement(senderFrameworkElement).try_as<winrt::DependencyObject>();
    auto isLastElementFocused = lastFocusableElement == focusedElement;
    if (!isLastElementFocused)
    {
      winrt::FocusManager::TryMoveFocus(winrt::FocusNavigationDirection::Next, findNextElementOptions);
      e.Handled(true);
    }
  } else if (e.Key() == winrt::Windows::System::VirtualKey::Tab) {
    auto const &coreWindow = winrt::CoreWindow::GetForCurrentThread();
    auto isShiftDown = KeyboardHelper::IsModifiedKeyPressed(coreWindow, winrt::Windows::System::VirtualKey::Shift);
    auto exclusionRect = winrt::Rect(ViewPanel::GetLeft(senderFrameworkElement), ViewPanel::GetTop(senderFrameworkElement), senderFrameworkElement.Width(), senderFrameworkElement.Height());
    // auto exclusionRect = winrt::LayoutInformation::GetLayoutSlot(sender.try_as<winrt::FrameworkElement>());
    findNextElementOptions.ExclusionRect(exclusionRect);

    auto nextElement = winrt::FocusManager::FindNextElement(isShiftDown ? winrt::FocusNavigationDirection::Up : winrt::FocusNavigationDirection::Down, findNextElementOptions);
    winrt::FocusManager::TryFocusAsync(nextElement, winrt::FocusState::Programmatic);
    e.Handled(true);
  }
}

} // namespace uwp
} // namespace react