With the introduction of the new MobileMapViewer for Android, users now have the ability to customize the behavior and appearance of MobileMapViewer instances. For example, they can hide the zoom controls by using SetZoomControlsEnabledXC(False), or enable/disable certain gestures (zoom, rotation, etc.). You can also set the minimum and maximum zoom level for the control by using the SetMaxZoomPreferenceXC or SetMinZoomPreferenceXC methods.

Android 15 users now also gain access to 16 additional system colors.

Give it a try! More exciting Android features are coming soon. Stay tuned!

Feel free to take a look at the developer repository, create feature requests, and provide feedback on extending this extension library.

I’m happy to receive any voluntary financial support for the work I’ve done so far, which you are welcome to share here. You can download the project with many examples at https://github.com/XojoGermany/AndroidDesignExtensions.

Happy coding.

Martin T. is a Xojo MVP and has been very involved in testing Android support.

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Before you can use MobileMapViewer you will need to have a Google Maps account configured so that you can generate an API Key. Instructions for doing this on available from Google: Google Maps Platform, Get Google Maps API Key.

Google Maps is not free to use. Although there is some free usage available for testing your app, your account does get billed based on usage once the small amount of free testing credits are used up.

When you have your API Key, you can add it to your Xojo project using a new App property. Select App in the Navigator and in the Inspector, put the key in the Google Maps API Key field. Note that the key is not saved with text projects and is instead saved as part of the UI state file that is local to the development machine. This prevents the key from being accidently committed to a source code repository.

With the configuration work out of the way, you can now use the control. Drag a MobileMapViewer from the Library onto a screen. When you run the project you’ll see an interactive map that you can swipe, zoom and move around as you like.

This code shows Fenway Park in Boston:

FenwayLocation = New MapLocation("Fenway Park, Boston, MA USA")
FenwayLocation.Title = "Fenway Park"

MapViewer1.ZoomRadius = 5
MapViewer1.GoToLocation(FenwayLocation) // Center map within radius km

MapViewer1.AddLocation(FenwayLocation) // Drop a pin

The MobileMapVIewer API matches what has already been in use for iOS. You can also use the MapLocation class to track specific locations. Although the overall API matches what has been used for iOS, there is one exception: MapLocation.PointsOfInterest() is not yet implemented. Implementing this requires another Google SDK and API Key (the Places API) and is being reviewed for a future release. We may also consider adding alternative mapping engines as well.

Note: You can’t get there from here is an old Maine saying.

Paul learned to program in BASIC at age 13 and has programmed in more languages than he remembers, with Xojo being an obvious favorite. When not working on Xojo, you can find him talking about retrocomputing at Goto 10 and on Mastodon @lefebvre@hachyderm.io.

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Getting the Image Metadata

In order to get the metadata from a given image, first retrieve a valid instance from the Picture Class using MobileImagePicker, select Photos or Camera as the image source.

Once we get the Picture instance, for example as the received parameter in the Selected event from the ImagePicker instance, we only need to access its Metadata property. The property will return a Dictionary instance, so we can iterate its entries or convert it to a JSONItem instance for simplicity if all you want to do is store the information. For example, we can use the following fragment of code in the Selected event of the ImagePicker instance:

Var js As JSONItem
Try
  js = New JSONItem(pic.Metadata)
  MessageBox(js.ToString)
Catch e As JSONException

End Try

Assuming that “pic” is the name of the received parameter that points to the user selected (or captured) image, the previous fragment of code will show a dialog with the image metadata.

Getting the Image Location… and Putting it On the Map!

An interesting action could be reading the location data of the selected image and adding an entry on a MobileMapViewer instance. So, for example, again in the Selected event of an ImagePicker instance, we could add the following snippet of code:

If pic <> Nil Then
  ImageViewer.Image = pic
  
  // The metadata is retrieved as a Dictionary, so let's get the
  // metadata from the selected picture
  metadata  = pic.Metadata
  
  If metadata <> Nil Then
    Var jlocation As Dictionary = metadata.Lookup("Location", Nil)
    
    // Getting the Location information (also as Dictionary)
    If jlocation <> Nil Then
      
      // And assigning the Latitude and Longitude
      // values to the properties
      latitude  = jlocation.Value("Latitude").DoubleValue
      longitude = jlocation.Value("Longitude").DoubleValue
      
      // Then, we will show the Picture location on the Map
      Timer.CallLater(100, AddressOf Showlocation)
    End If
    
  End If
  
End If

Latitude and Longitude are Double type properties that have been added to the Screen containing the ImagePicker instance, also added is an ImageViewer instance responsible for displaying the selected image preview, and a MapViewer instance on which the “pin” corresponding to the location of the image will be added.

As you can see, the shared method CallLater of the Timer class is used to invoke the ShowLocation method. This method will be responsible for displaying the actual pin on the map:

Private Sub Showlocation()
  // Let's create a new Location instance from the stored
  // latitude and longitude values in order to add it
  // to the Mapviewer…
  
  Var maplocation As New MapLocation(latitude, longitude)
  MapViewer1.AddLocation(maplocation)
  
  // …and let's make sure the metadata is updated
  // to the viewed image
  ImageViewer.Image.Metadata = metadata
End Sub

The following screenshot shows the outcome of executing the previous code:

Of course, you’ll need to enable the Maps entitlement in the Build Settings > iOS > Capabilities inspector.

Setting the Location in a Picture

Just as we can get the location out of an image, we can also modify it… or set a location to those photographs that we get through the ImagePicker using the Camera source. Assigning a location is very simple:

• Add an instance of MobileLocation to the project (for example the screen where we manage image capture).
• Add the Latitude and Longitude properties of type Double as two new properties on the same screen.
• In the LocationChanged event of the MobilLocation instance assign the values received in the Latitude and Longitude parameters to the properties created previously:

Self.Latitude = Latitude
Self.Longitude = Longitude

• Then, in the Selected event of the ImagePicker instance, use the following snippet of code:

Var d As New Dictionary
d.Value("Latitude") = Self.Latitude
d.Value("Longitude") = Self.Longitude

Var Location As New Dictionary
Location.Value("Location") = d

pic.Metadata = Location

Saving Pictures to Photos

Until now, MobileSharingPanel was probably the go-to option when it came to saving any of the images generated in your iOS Xojo app or images captured with the camera using the ImagePicker. Starting with Xojo 2024r3, you can also use the SaveToPhotos method of the Picture class, which will take care of saving the image while preserving the associated metadata.

So, for example, you will only have to add the following line of code at the end of the previous block so that the captured image is saved with the location:

pic.SaveToPhotos(Picture.Formats.PNG)

However, when using this method on images in your iOS app, make sure to enable the Photos Access capability in the Build Settings > iOS > Capabilities Inspector Panel.

Wrapping-Up

As you have seen, it’s now really easy to get metadata from Picture instances in your Xojo iOS apps, as well as leverage Location information and assign location information to any of existing or new images. Plus, you no longer need to resort to MobileSharingPanel if all you want is your iOS app to save images to the Photos app album on the iOS device.

Javier Menendez is an engineer at Xojo and has been using Xojo since 1998. He lives in Castellón, Spain and hosts regular Xojo hangouts en español. Ask Javier questions on Twitter at @XojoES or on the Xojo Forum.

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