Android Question Problem with BLE in Android 7 & 8

[Jaume Guillem]

Hi.
I have a curious problem using BLE with Android 7 & 8.

Mi app worked for years in versions 6 and lower of Android, and with Bluetooh 3 and BLE. Allways without problems.

I introduced the necessary modifications to run Android 7 and 8.

Manifest:

<uses-sdk android:minSdkVersion="5" android:targetSdkVersion="27"/>
AddPermission(android.permission.ACCESS_COARSE_LOCATION)
AddPermission(android.permission.ACCESS_FINE_LOCATION)

Sub Activity_Create(FirstTime As Boolean)
rp.CheckAndRequest(rp.PERMISSION_ACCESS_FINE_LOCATION)
....
end sub

Sub Activity_PermissionResult (Permission As String, Result As Boolean)
   Select Case Permission
   Case rp.PERMISSION_WRITE_EXTERNAL_STORAGE
              If Result Then
                    ToastMessageShow("Permission OK",True)
              End If
     Case rp.PERMISSION_ACCESS_FINE_LOCATION
               If Result Then
                     ToastMessageShow("BT Permission OK",True)
               End If
            End Select
End Sub

It produces a curious effect ONLY running in a device with Android 7 (and 8 I suppose)

After scanning, the Manager_DeviceFound is fired correctly

Sub Manager_DeviceFound (Name As String, Id As String, AdvertisingData As Map, RSSI As Double)
        If Id=Starter.StoredId then
                manager.Connect2(Id,False)
        end if
end sub

But Immediately after Connect2 (and Connect also), the event fired is Manager_Disconnected
(instead of Manager_Connected)

If I run the app in a phone with Android 4 or 5, all is working perfect.

And I don’t know how to manage this. Any idea?
I’m using B4A 8.0 and BLE2 V 1.36

Thank you very much

 

[Erel]

It is a mistake to set targetSdkVersion to 27.

Try this example: https://www.b4x.com/android/forum/threads/ble-2-bluetooth-low-energy.59937/
Does it work for you?

 

[Jaume Guillem]

Thanks for the idea, but it does not work. Same problem.
The behavior of the example and my app is the same (after putting sdk = 26)
I tried with three different devices and always the same. Scan is correct, but when I call manager.Scan2(Null, False) , the event fired is Manager_Disconnected

This is with a BM77 (a Microchip device)

Logger connected to:  samsung SM-J530F
--------- beginning of main
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
Class not found: b4a.example.customlistview, trying: b4a.example3.customlistview
** Activity (main) Resume **
** Activity (main) Pause, UserClosed = false **
sending message to waiting queue (activity_permissionresult)
running waiting messages (1)
** Activity (main) Resume **
Found: Test 1          , 34:81:F4:14:B1:D9, RSSI = -59, (MyMap) {1=[B@367ab89, 9=[B@e5df78e, 0=[B@543dbaf}
Disconnected
Found: Test 1          , 34:81:F4:14:B1:D9, RSSI = -64, (MyMap) {1=[B@1fc83cb, 9=[B@2ae27a8, 0=[B@82c42c1}
Disconnected

and this with a Contour (a glucose monitor)

** Activity (main) Resume **
Found: Contour7801H5104382, 24:71:89:0D:75:39, RSSI = -47, (MyMap) {1=[B@fb4bd53, 2=[B@2d61690, -1=[B@367ab89, 9=[B@e5df78e, 0=[B@543dbaf}
Disconnected
Found: Contour7801H5104382, 24:71:89:0D:75:39, RSSI = -48, (MyMap) {1=[B@1fc83cb, 2=[B@2ae27a8, -1=[B@82c42c1, 9=[B@9756a66, 0=[B@e4d91a7}
Disconnected

Testing more than thirty times, ONE connection has been successful.
I tried to delay the connection one or two seconds, in case this was the problem, but there is no variation.

Trying SDK=21 and lower, the problem persist.
The phone is a Samsung J5 2017 with Android 7.
With a Samsung S4 Android 4.4.2 works perfect

Thanks for your help

 

[Erel]

It is possible that the problem is in the specific phone.

 

[Jaume Guillem]

It is my opinion too.
I will have no choice but to publish it as it is.
I hope it's just this phone.
Thank you