Android Question Google Maps Get click location

[foakgul]

Hello,

Ok, so very simple question. I've searched a lot about this and found a sample code (webview and javascript) but kinda confused as this code does not seem to handle "click" message passing from javascript.

Goal: Program should center the map around current GPS location and clicked location lat/lon should be obtained.

Question: How do I get the GPS lat/lon of a clicked location on Google Maps? Adding a marker at this location is fine.

Code I'm trying:

Sub Activity_Create(FirstTime As Boolean)
    gpstimer.Initialize("gpstimer",20000)
    gpstimer.Enabled = False
    gps1.Initialize("GPS")
 
    If gps1.GPSEnabled = False Then
        ToastMessageShow("Turn on GPS.", True)
        StartActivity(gps1.LocationSettingsIntent) 'Will open the relevant settings screen.
    Else
        gps1.Start(0, 0) 'Listen to GPS with no filters.
        gpstimer.enabled = True
    End If
 
   WebView1.Initialize("WebView1")
 
   '   use WebViewExtras to add the JavascriptInterface to the WebView
   '   the javascript can now call B4A Subs
   Dim WebViewExtras1 As WebViewExtras
   WebViewExtras1.addJavascriptInterface(WebView1, "B4A")
   Activity.LoadLayout("test.bal")

   WebView1.LoadUrl("file:///android_asset/draggable-markers.html")

End Sub

Sub Map_Ready
 
   Log("map ready")
   gmap = mFragment.GetMap
 
   If gmap.IsInitialized = False Then
      ToastMessageShow("Error initializing map.", True)
   Else
      m1=gmap.AddMarker(INIT_LAT, INIT_LON, "Hello!!!")
     Dim cp As CameraPosition
      cp.Initialize(INIT_LAT, INIT_LON, gmap.CameraPosition.Zoom)
      gmap.AnimateCamera(cp)
     m1.Draggable = True
     EditText1.Text = m1.Position.Latitude & "," & m1.Position.Longitude
   End If
   markerDragListener.Initialize("markerDragListener")
   GoogleMapsExtras1.SetOnMarkerDragListener(gmap,markerDragListener)
End Sub

''''This function does not seem to work!!!
Sub markerDragListener_DragEnd(NewLatitude As String, NewLongitude As String)
   '   only String types can be passed from the javascript to B4A so we need to convert the String types to Double
   Dim lat As Double=NewLatitude
   Dim lon As Double=NewLongitude
   EditText1.Text = lat & "," & lon
End Sub

Sub gpstimer_Tick
    Msgbox("No GPS!","")
    gpstimer.Enabled = False
    gps1.Stop
End Sub

Sub GPS_LocationChanged (Location1 As Location)
    EditText1.Text = NumberFormat(Location1.Latitude,0,6) & "," & NumberFormat(Location1.Longitude,0,6)
    INIT_LAT = Location1.Latitude
    INIT_LON = Location1.Longitude
    gps1.Stop
    gpstimer.Enabled = False
End Sub

 

[Erel]

You should handle the Map_Click event.

 

[foakgul]

Thanks Erel! Is there any sample use of this function (sub) that I can use?

 

[Erel]

Sub Map1_Click (Point As LatLng)
   Log("Point: " & Point.Latitude & ", " & Point.Longitude)
End Sub

 

[eurojam]

It seems that you are mixing Google Maps Javascript Api (->https://developers.google.com/maps/documentation/javascript/basics) and the Google Maps Android Api. The first handles all events with javascript, whereas the second uses the events like Erel pointed out (see https://www.b4x.com/android/forum/threads/google-maps-android-v2-tutorial.24415/ for more information). As you use your gmap within a webview, you should use the javascript Api.

best regards
stefan

 

[foakgul]

Hi Stefan, actually the very first example I found was Google Maps javascript Api and that's why I started using it and possibly I found another Google Maps Android api and mixed them. However, if Google Maps Android Api is easier (less cumbersome) and if it's easier to handle within B4A, I'd prefer to use it by itself.

I'll go thru the thread that you sent, thanks a lot!

 

[foakgul]

Erel's method turned out to be much easier! Thanks a lot!