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Implementing location in AL

  • Artikkeli

You can access the location information of a device from the Business Central Web client in the browser and from the Business Central Mobile App. This functionality could be useful in scenarios such as calculating routes from the current location or planning the next round of customer visits based on their addresses.

You can also add access to location information to a specific page from the AL Language development environment. For a Dynamics 365 Business Central existing implementation of this, see the Show On Map link on the Customer Card, which displays a map that shows where your customer is located based on the GPS coordinates and gives directions to reach its location.

Important

Location information is only available on devices that are able to obtain location coordinates, such as using GPS capabilities.

Example

This example illustrates how to implement the location capability on a page in AL. The example implements a GetLocation action on a page that returns the coordinates of the current customer's address, but does not save this information to the database.

The example also shows how to specify options for the location functionality such as setting a timeout or enabling high accuracy. For more information about the different options that can be set for location, see LocationOptions Overview.

Note

To enable the location functionality, it is required that you add the path of the folder containing the "Microsoft.Dynamics.Nav.ClientExtensions" assembly on the Al: Assembly Probing Paths setting on the User Settings or Workspace Settings so the compiler can access it. For more information, see Getting started with Microsoft .NET Interoperability from AL.

The following code will create two variables; the LocationAvailable variable is a Boolean that checks whether the current device has location capabilities. The Location variable is a DotNet type that gets instantiated by adding code to the OnOpenPage trigger. Then, it will add an action to the page that lets the user retrieve the location information. Finally, the trigger Location::LocationChanged is defined to handle the incoming location information.

page 50101 "Card with Location Capability"
{

    Caption = 'Card Page';
    PageType = Card;
    RefreshOnActivate = true;
    SourceTable = "Test Table";

    layout
    {
        area(content)
        {
            //...
        }
    }

    actions
    {
        area(Processing)
        {
            action(GetLocation)
            {
                Visible = LocationAvailable;
                Promoted = true;
                PromotedCategory = Process;
                PromotedIsBig = true;
                Image = Map;

                trigger OnAction()
                begin
                    LocationOptions := LocationOptions.LocationOptions;
                    LocationOptions.EnableHighAccuracy();
                    Location.RequestLocationAsync();
                end;
            }
        }

    }

    trigger OnOpenPage()
    begin
        if Location.IsAvailable() then begin
            Location := Location.Create();
            LocationAvailable := true;
        end;
    end;

    trigger Location::LocationChanged(Location: DotNet Location)
    begin
        // Location.Status can be: 
        //      0 = Available 
        //      1 = NoData (no data could be obtained)
        //      2 = TimedOut (location information not obtained in due time)
        //      3 = NotAvailable (for example user denied app access to location)
        if Location.Status = 0 then
            Message('Your position: %1 %2', Location.Coordinate.Latitude, Location.Coordinate.Longitude)
        else
            Message('Position not available');
    end;

    var
        [RunOnClient]
        [WithEvents]
        Location: DotNet LocationProvider;
        LocationAvailable: Boolean;
        LocationOptions: DotNet UT_LocationOptions;
}

dotnet
{
    assembly("Microsoft.Dynamics.Nav.ClientExtensions")
    {

        type("Microsoft.Dynamics.Nav.Client.Capabilities.LocationProvider"; LocationProvider)
        {

        }

        type("Microsoft.Dynamics.Nav.Client.Capabilities.Location"; Location)
        {

        }

        type("Microsoft.Dynamics.Nav.Client.Capabilities.LocationOptions"; UT_LocationOptions)
        {

        }
    }
}

For information about troubleshooting access to location information, see Troubleshooting: Camera and Location.

Getting started with Microsoft .NET Interoperability from AL
LocationOptions Overview
Troubleshooting: Camera and Location
Implementing the Camera in AL
RunOnClient property
WithEvents property