/// <summary>
/// Navigates to next (down) item or directional focus object if possible on key input
/// </summary>
/// <param name="e">EventArgs describing key input</param>
private void NavigateDown(KeyEventArgs e)
{
ApplicationNavigationAction action = GetApplicationNavigationActionForKeyEvent(e);
if (action != ApplicationNavigationAction.None)
{
switch (action)
{
case ApplicationNavigationAction.NavigateFromSection:
GoToNextSection();
e.Handled = true;
break;
case ApplicationNavigationAction.NavigateFromStory:
// Execute NextPage command for StoryViewer, which is configured to go to next story if next page cannot execute
StoryViewer storyViewer = Keyboard.FocusedElement as StoryViewer;
if (storyViewer != null)
{
if (System.Windows.Input.NavigationCommands.NextPage.CanExecute(null, storyViewer))
{
System.Windows.Input.NavigationCommands.NextPage.Execute(null, storyViewer);
}
e.Handled = true;
}
break;
default:
break;
}
}
}
/// <summary>
/// Navigates to next (right) item or directional focus object if possible on key input
/// </summary>
/// <param name="e">EventArgs describing key input</param>
private void NavigateRight(KeyEventArgs e)
{
ApplicationNavigationAction action = GetApplicationNavigationActionForKeyEvent(e);
if (action != ApplicationNavigationAction.None)
{
switch (action)
{
case ApplicationNavigationAction.NavigateFromSection:
case ApplicationNavigationAction.NavigateFromStory:
GoToNextStory();
e.Handled = true;
break;
default:
break;
}
}
}
/// <summary>
/// Gets the appropriate navigation action for key input
/// </summary>
/// <returns>Navigation action to perform for the key input</returns>
private ApplicationNavigationAction GetApplicationNavigationActionForKeyEvent(KeyEventArgs e)
{
ApplicationNavigationAction action = ApplicationNavigationAction.None;
switch (e.Key)
{
case Key.Left:
case Key.Right:
case Key.Up:
case Key.Down:
case Key.I:
case Key.J:
case Key.K:
case Key.M:
case Key.Space:
case Key.PageDown:
case Key.PageUp:
if (ServiceProvider.ViewManager.CurrentNavigator is SectionNavigator)
{
if (ServiceProvider.ViewManager.CurrentNavigator is ReadingListNavigator ||
ServiceProvider.ViewManager.CurrentNavigator is SearchNavigator)
{
// For reading list and search UI, the main content visual is not focusable, and won't have the focus
// Since this UI is application-based (unlike SectionFrontControl) the application can choose to handle
// navigation keys regardless of what the event source is. For these sections, the application does not
// handle up or down keys, since they are not connected to other sections and up and down should
// navigate reading list items/ search results. But left and right keys navigate stories
if (e.Key == Key.Left || e.Key == Key.Right)
{
action = ApplicationNavigationAction.NavigateFromSection;
}
}
else
{
// Sections don't have a fixed template, may be different for search, reading list, etc
// In general, check that source is the current content visual, section fronts are a special case because they steal
// focus from the current content visual
// Application authors may change this code to recognize their custom controls for focus manipulation
UIElement source = e.OriginalSource as UIElement;
UIElement currentContentVisual = ServiceProvider.ViewManager.CurrentVisual as UIElement;
if (currentContentVisual != null && source != null)
{
if (source == currentContentVisual || source is SectionFrontControl)
{
action = ApplicationNavigationAction.NavigateFromSection;
}
}
}
}
else if (ServiceProvider.ViewManager.CurrentNavigator is StoryNavigator)
{
// Check that a StoryViewer is focused, since annotation layer may be topmost in stories if user is making notes
// In such a case navigation should not take place on key input
if (e.OriginalSource is StoryViewer)
{
action = ApplicationNavigationAction.NavigateFromStory;
}
}
break;
default:
break;
}
return(action);
}
