Android Question Google Maps

[Sergey_New]

Please help me indicate "My location" on Google Maps.

 

[DonManfred]

Please help me indicate "My location" on Google Maps.

See the GoogleMaps Tutorial.
You need to request permission and when given you can set the MyLocationEnabled flag to true.

Google Maps

Installation instructions: - Register your app in Google developer console: https://console.developers.google.com You need to enable Google Maps Android API. Then click on Credentials -> Create Credentials -> API Key -> Android Key. You should get a key that looks like...

www.b4x.com

 

[Sergey_New]

See the GoogleMaps Tutorial.

Here's my code

Spoiler

Sub Process_Globals
    Private rp As RuntimePermissions
End Sub

Sub Globals
    Private gmap As GoogleMap, frag As MapFragment, marc As Marker, pos As CameraPosition
    Dim CenterLat, CenterLong As Float
    Dim pnlAB As Panel
    Dim Title As Label
    Dim Menu As ImageView
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("gmap")
    Menu.Visible=False
End Sub

Sub ShowMap(coordinates() As Float, name As String)
    Title.Text=name
    Title.TextSize=Starter.TextSize
    CenterLat=coordinates(0)
    CenterLong=coordinates(1)
    If frag.IsGooglePlayServicesAvailable = False Then Return
'    For Each permission As String In Array(rp.PERMISSION_ACCESS_FINE_LOCATION)
'        rp.CheckAndRequest(permission)
'        Wait For Activity_PermissionResult (permission As String, Result As Boolean)
'        If Result = False Then
'            ToastMessageShow("No permission!", True)
'            Activity.Finish
'            Return
'        Else
'            gmap.MyLocationEnabled=True
'        End If
'    Next
End Sub

Sub frag_Ready
    gmap = frag.GetMap
    pos.Initialize(CenterLat, CenterLong, 10)
    gmap.MoveCamera(pos)
    If marc.IsInitialized Then marc.Remove
    marc = gmap.AddMarker2(pos.Target.Latitude, pos.Target.Longitude, Activity.Title, gmap.HUE_GREEN)
End Sub

Everything is working.
If you uncomment part of the code, an error occurs.

 

[Sergey_New]

If you uncomment part of the code, an error occurs.

Corrected the code

Spoiler

Sub frag_Ready
    gmap = frag.GetMap
    pos.Initialize(CenterLat, CenterLong, 10)
    gmap.MoveCamera(pos)
    If marc.IsInitialized Then marc.Remove
    marc = gmap.AddMarker2(pos.Target.Latitude, pos.Target.Longitude, Activity.Title, gmap.HUE_GREEN)
    For Each permission As String In Array(rp.PERMISSION_ACCESS_FINE_LOCATION)
        rp.CheckAndRequest(permission)
        Wait For Activity_PermissionResult (permission As String, Result As Boolean)
        If Result = False Then
            ToastMessageShow("No permission!", True)
            Activity.Finish
            Return
        Else
            gmap.MyLocationEnabled=True
        End If
    Next
End Sub

The map shows my position.
Tell me how to set my own icon for my position and get its coordinates?

 

[Andrew (Digitwell)]

Use gmap.myLocation

You can create your own marker with gmap.addMarker3

You can do this in a timer loop

OR

you can use the GPS object and listen to the location changed event

which will do the same thing and then use AddMarker3 to display your own marker.

You will need to turn off MyLocationEnabled
#

 

[Sergey_New]

Use gmap.myLocation

Please show the code, not screenshots.

 

[Andrew (Digitwell)]

private sub timer_tick
private myLoc as Latlng = gmap.myLocation
if (myLoc <> Null) then
  if (theMarker <> null) then
    theMarker.remove
  end if
  theMarker = gmap.addMarker3(myLoc.latitude,myLoc.Longitude,"You are here",LoadBitmap(File.dirassets,"mypng.png")
end if

theMarker is a global marker variable.

 

[Sergey_New]

theMarker is a global marker variable.

Thank you! Show the code for the first screenshot.

 

[Andrew (Digitwell)]

Line 2 of the code provided gets myLocation.

If you want to use the GPS object alternative, there are plenty of examples on the forum showing how to use.

 

[Sergey_New]

I did this:

Sub frag_Ready
    gmap = frag.GetMap
    pos.Initialize(CenterLat, CenterLong, 10)
    gmap.MoveCamera(pos)
    If marc.IsInitialized Then marc.Remove
    marc = gmap.AddMarker2(pos.Target.Latitude, pos.Target.Longitude, Title, gmap.HUE_GREEN)
    For Each permission As String In Array(rp.PERMISSION_ACCESS_FINE_LOCATION)
        rp.CheckAndRequest(permission)
        Wait For Activity_PermissionResult (permission As String, Result As Boolean)
        If Result = False Then
            ToastMessageShow("No permission!", True)
            Activity.Finish
            Return
        Else
            gmap.MyLocationEnabled=True
            Sleep(3000)
            Log(gmap.myLocation.Latitude)
        End If
    Next
End Sub

At the first launch, everything works without a delay, but upon repeated launches I had to introduce a delay of 3 seconds, otherwise an error occurs.

 

[Andrew (Digitwell)]

What error?

It is not clear why you would want to loop over only 1 permission

The code looks fine, but will only be executed once, when the map fragment is ready. You will need to post an the whole project.

 

[Sergey_New]

It is not clear why you would want to loop over only 1 permission

I’m checking one resolution, because that’s how it was in the example. I check the other ones I need in the main module B4A. This

Spoiler

    For Each permission As String In Array(rp.PERMISSION_READ_CONTACTS, rp.PERMISSION_WRITE_EXTERNAL_STORAGE)
        rp.CheckAndRequest(permission)
        Wait For Activity_PermissionResult (permission As String, Result As Boolean)
        If Result = False Then
            Activity.Finish
            Return
        End If
    Next

So wrong?

 

[Andrew (Digitwell)]

I would have thought you would want to perform different actions if each permission is denied.

What was the error?

 

[Sergey_New]

What was the error?

Error:

Spoiler

mainmenu_setdata (java line: 722)
java.lang.NullPointerException: Attempt to invoke virtual method 'int anywheresoftware.b4a.objects.collections.Map.getSize()' on a null object reference
    at sv.bystrovzorov.mainmenu._setdata(mainmenu.java:722)
    at sv.bystrovzorov.mainmenu._activity_resume(mainmenu.java:486)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:221)
    at anywheresoftware.b4a.BA.raiseEvent(BA.java:201)
    at sv.bystrovzorov.mainmenu.afterFirstLayout(mainmenu.java:111)
    at sv.bystrovzorov.mainmenu.access$000(mainmenu.java:17)
    at sv.bystrovzorov.mainmenu$WaitForLayout.run(mainmenu.java:83)
    at android.os.Handler.handleCallback(Handler.java:958)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loopOnce(Looper.java:230)
    at android.os.Looper.loop(Looper.java:319)
    at android.app.ActivityThread.main(ActivityThread.java:8919)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:578)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1103)
*** Service (starter) Create ***
Using FileProvider? true
** Service (starter) Start **
** Activity (main) Create (first time) **
** Activity (main) Resume **
** Activity (main) Pause, UserClosed = false **
** Activity (loader) Create (first time) **
** Activity (loader) Resume **
** Activity (loader) Pause, UserClosed = false **
Sleep not resumed (context is paused): sv.bystrovzorov.circularprogressbar$ResumableSub_AnimateValueTo
** Activity (mainmenu) Create (first time) **
** Activity (mainmenu) Resume **

I'll try to track it in debug mode, if I can avoid stopping on bookmarks. When stopping, the error does not occur.

 

[AnandGupta]

Wise man advise: When breakpoints does not solve, use Log()

 

[Andrew (Digitwell)]

The error you displayed has nothing to do with the code you provided.

it is in mainmenu.setdata.

You need to read the error message.

 

[Andrew (Digitwell)]

Also there is no need to use Spoiler all the time.

 

[Sergey_New]

I made an example.
It shows that without setting the delay, gmap.myLocation does not have time to initialize.
I'm asking for advice on how to improve the project.

 

[Andrew (Digitwell)]

The key problem is that you did not follow the example properly.

You manifest is missing the following lines

AddApplicationText(
<uses-library
      android:name="org.apache.http.legacy"
      android:required="false" />
)

with that the code works for me.

Yes, it take a short while for the mobile app to get a lock on the GPS satellites and start reporting locations. This is perfectly normal.

Add a timer, and check MyLocation in the timer rather than in the initialisemap code.

There is a lot of extra code such as
#AdditionalJar: com.google.android.gmslay-services-maps

which is necessary now.

I also would not have an activity called GoogleMap.

Not sure why you are adding all those permissions in the Manifest, this is unnecessary also.

 

[Sergey_New]

You manifest is missing the following lines

This is in the main program, I just carelessly transferred it to the example.

Not sure why you are adding all those permissions in the Manifest, this is unnecessary also.

For the same reason

Add a timer, and check MyLocation in the timer

Никогда не использовал его раньше. Подскажите пожалуйста, как это сделать правильно.
Спасибо за участие и советы!