/// <summary>
/// Detach webview elements when we navigate off the page.
/// </summary>
/// <param name="e">Argument of the navigation event.</param>
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
RunOnUI(() =>
{
/* Remove notification from grid. */
if (mEngagementGrid.Children.Contains(mNotification))
{
mNotification.UnsetHandler();
mEngagementGrid.Children.Remove(mNotification);
}
/* Remove announcement from grid. */
if (mAnnouncementGrid.Children.Contains(mAnnouncement))
{
mAnnouncement.UnsetHandler();
mAnnouncementGrid.Children.Remove(mAnnouncement);
}
/* Forward navigation event. */
base.OnNavigatedFrom(e);
});
}
/// <summary>
/// Initialize overlay on the current page.
/// </summary>
public void InitOverlay()
{
/* We have to use RunOnUI to ensure to be in the same thread pool than UI */
#pragma warning disable 4014
RunOnUI(() =>
{
/* EngagementGrid is locked to ensure fast switching between page doesn't crash the app. */
lock (thisLock)
{
mEngagementGrid = new Grid();
mAnnouncementGrid = new Grid();
/* Check if customer have tagged grids with "engagementGrid" or "announcementGrid" */
mEngagementGrid = FindChildControl <Grid>(Window.Current.Content, "engagementGrid") as Grid;
mAnnouncementGrid = FindChildControl <Grid>(Window.Current.Content, "announcementGrid") as Grid;
/* Pick the first element found on the grid. */
if (mEngagementGrid == null)
{
mEngagementGrid = FindChildControl <Grid>(Window.Current.Content, "") as Grid;
}
if (mAnnouncementGrid == null)
{
mAnnouncementGrid = FindChildControl <Grid>(Window.Current.Content, "") as Grid;
}
/* Take unique instance of Engagement UI elements to add them on the Engagement grid. */
mNotification = EngagementOverlayNotification.Instance;
mAnnouncement = EngagementOverlayAnnouncement.Instance;
/* If we have a grid then insert the overlay in it. */
if (mEngagementGrid != null)
{
/* Check that notification is not already set. */
if (!mEngagementGrid.Children.Contains(mNotification))
{
/* Add it. */
try
{
mEngagementGrid.Children.Add(mNotification);
}
catch (Exception)
{
/* Because of threading context we can face an unexpected error due to webview insertion.
* But we have to ensure overlay creation. */
InitOverlay();
return;
}
/* Set the display_orientation_change event to resize the notification. */
mNotification.SetHandler();
/* Make the first resize to be sure to match the current application size. */
mNotification.SetWebView();
}
}
else
{
mNotification.UnsetHandler();
}
if (mAnnouncementGrid != null)
{
/* Check an announcement is already set. */
if (!mAnnouncementGrid.Children.Contains(mAnnouncement))
{
/* Add it. */
try
{
mAnnouncementGrid.Children.Add(mAnnouncement);
}
catch (Exception)
{
/* Because of threading context we can face an unexpected error due to webview insertion.
* But we have to ensure overlay creation. */
InitOverlay();
return;
}
/* Set the display_orientation_change event to resize the notification. */
mAnnouncement.SetHandler();
/* Make the first resize to be sure to match the current application size. */
mAnnouncement.SetWebView();
}
}
else
{
mAnnouncement.UnsetHandler();
}
if (mEngagementGrid == null || mAnnouncementGrid == null)
{
mEngagementGrid = new Grid();
mAnnouncementGrid = new Grid();
/* Run again the init because sometime graphical context isn't set fine. */
InitOverlay();
}
}
});
}