protected override void OnNavigatedTo(NavigationEventArgs e)
{
base.OnNavigatedTo(e);
// initialize orientation (used later when determine if map view requires update)
_priorOrientation = ApplicationView.Value;
// register data callback for sharing
var dtm = DataTransferManager.GetForCurrentView();
dtm.DataRequested += LeftPanel.GetSharedData;
// Navigate to new destination
if (e.NavigationMode == NavigationMode.New)
{
LatLong destination;
LatLong.TryParse(e.Parameter as String, out destination);
GotoLocation(destination, showMessage: !_firstRun);
}
else
{
// refresh the point-of-interest list given coordinates saved in page state. Note that Refresh is async, but
// we are not awaiting it to lessen risk that a resume operation will timeout
if (_pageState.MapBox != null)
{
LeftPanel.Refresh(_pageState.MapBox, _pageState.SelectedItemId);
}
// reset map to last known view
_retainRefreshRequiredViewChange = true;
TheMap.SetView(new Location(_pageState.MapCenter.Latitude, _pageState.MapCenter.Longitude), _pageState.Zoom, MapAnimationDuration.None);
}
}
/// <summary>
/// Fires when map panning is complete, and the current bounds of the map can be accessed to apply the points of interest
/// (note that using TargetBounds in lieu of the event handler led to different results for the same target location depending on
/// the visibilty of the map at the time of invocation - i.e., a navigation initiated from the search results pages reported sligthly
/// offset TargetBounds
/// </summary>
async void TheMap_ViewChangeEndedWithRefreshNeeded(object sender, ViewChangeEndedEventArgs e)
{
// refresh the left panel to reflect points of interest in current view
await LeftPanel.Refresh(new BoundingBox(TheMap.TargetBounds.North, TheMap.TargetBounds.South, TheMap.TargetBounds.West, TheMap.TargetBounds.East));
// unregister the handler
TheMap.ViewChangeEnded -= TheMap_ViewChangeEndedWithRefreshNeeded;
}
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
base.OnNavigatedFrom(e);
// unregister data callback for sharing
var dtm = DataTransferManager.GetForCurrentView();
dtm.DataRequested -= LeftPanel.GetSharedData;
// stop the autorefresh of the cameras since we're navigating away from the page
LeftPanel.StopRefreshing();
}
public MainPage()
{
this.InitializeComponent();
// view model
this.DefaultViewModel["PendingRefresh"] = false;
// check to see if this is the first time application is being executed by checking for data in local settings.
// After checking add some notional data as marker for next time app is run. This will be used to determine whether
// to prompt the user (or not) that location services are not turned on for the app/system. Without this check, the
// first time the app is run, it will provide a system prompt, and if that prompt is dismissed without granting
// access the propmpt displayed by the application would also appear unnecessarily.
_firstRun = ApplicationData.Current.LocalSettings.Values.Count == 0;
if (_firstRun)
{
ApplicationData.Current.LocalSettings.Values.Add(
new System.Collections.Generic.KeyValuePair <string, object>("InitialRunDate", DateTime.UtcNow.ToString()));
}
this.SizeChanged += (s, e) =>
{
// determine if there's been a change in orientation that doesn't require notice that the map view has changed (e.g., app open, snapped mode transitions)
if (_priorOrientation == ApplicationView.Value)
{
return;
}
_noRefreshRequiredViewChange = (_priorOrientation == ApplicationViewState.Snapped || ApplicationView.Value == ApplicationViewState.Snapped);
_priorOrientation = ApplicationView.Value;
VisualStateManager.GoToState(LeftPanel, ApplicationView.Value.ToString(), true);
};
// whenever map view changes track center point and zoom level in page state
TheMap.ViewChangeEnded += (s, e) =>
{
// save new center/zoom for page state
_pageState.MapCenter = new LatLong(TheMap.TargetCenter.Latitude, TheMap.TargetCenter.Longitude);
_pageState.Zoom = TheMap.TargetZoomLevel;
// ViewChangeEnded fires a bit too often, so retain bounding box to determine if the view truly has changed
BoundingBox thisBox = new BoundingBox(TheMap.TargetBounds.North, TheMap.TargetBounds.South,
TheMap.TargetBounds.West, TheMap.TargetBounds.East);
// determine if view change should notify user of pending refresh requirement
if (_retainRefreshRequiredViewChange)
{
this.DefaultViewModel["PendingRefresh"] = _pageState.PendingRefresh;
}
else if (_noRefreshRequiredViewChange)
{
this.DefaultViewModel["PendingRefresh"] = false;
}
else if (App.InitialMapResizeHasOccurred)
{
this.DefaultViewModel["PendingRefresh"] = (thisBox != _lastBox);
}
// update state variables
_lastBox = thisBox;
if (App.InitialMapResizeHasOccurred)
{
_noRefreshRequiredViewChange = false;
}
_retainRefreshRequiredViewChange = false;
App.InitialMapResizeHasOccurred = true;
};
// if refresh prompt is tapped, refresh the map
RefreshPrompt.Tapped += async(s, e) =>
{
await LeftPanel.Refresh(_lastBox);
this.DefaultViewModel["PendingRefresh"] = false;
};
// a tap on map will cause refresh is one is predicated
TheMap.Tapped += async(s, e) =>
{
if ((Boolean)this.DefaultViewModel["PendingRefresh"])
{
await LeftPanel.Refresh(_lastBox);
this.DefaultViewModel["PendingRefresh"] = false;
}
};
// set the reference to the current map for the LeftPanel (note: using Element binding will not handle all of the page navigation scenarios)
LeftPanel.Map = TheMap;
// whenever the contents of left panel are refreshed, save the map coordinates that were in play as part of the page state
LeftPanel.Refreshed += (s, e) =>
{
_pageState.MapBox = new BoundingBox(TheMap.TargetBounds.North, TheMap.TargetBounds.South, TheMap.TargetBounds.West, TheMap.TargetBounds.East);
};
// whenver a new item is selected in the left panel, update the map pins and save the item selected as part of the page state
LeftPanel.ItemSelected += (s, e) =>
{
TheMap.HighlightPointOfInterestPin(e.NewItem, true);
TheMap.HighlightPointOfInterestPin(e.OldItem, false);
this._pageState.SelectedItemId = e.NewItem == null ? null : e.NewItem.Id;
};
// whenever a new location is selected from the SearchFlyout (this is NOT the Search charm) update the position accordingly
SearchFlyout.LocationChanged += (s, e) =>
{
GotoLocation(e.Position);
SearchFlyout.Hide();
};
// manage SearchFlyout visibility/interaction
this.Tapped += (s, e) =>
{
if (SearchFlyout.IsOpen)
{
SearchFlyout.Hide();
e.Handled = true;
}
};
BottomAppBar.Opened += (s, e) => { SearchFlyout.Hide(); };
SearchFlyout.Tapped += (s, e) => { e.Handled = true; };
// allow type-to-search for Search charm
SearchPane.GetForCurrentView().ShowOnKeyboardInput = true;
// The BingMaps API allows use of a "session key" if the application leverages the Bing Maps control. By using the session
// key instead of the API key, only one transaction is logged agains the key versus one transaction for every API call! This
// code sets the key asynchronously and stored it as a resource so it's available when the REST API's are invoked.
TheMap.Loaded += async(s, e) =>
{
if (!Application.Current.Resources.ContainsKey("BingMapsSessionKey"))
{
Application.Current.Resources.Add("BingMapsSessionKey", await TheMap.GetSessionIdAsync());
}
};
}
private async void Refresh_Click(object sender, RoutedEventArgs e)
{
await LeftPanel.Refresh(new BoundingBox(TheMap.TargetBounds.North, TheMap.TargetBounds.South,
TheMap.TargetBounds.West, TheMap.TargetBounds.East));
}
