Hello
We are working with these devices, https://store.kontakt.io/next-generation/43-asset-tag-s18-3.html.
We have a service that runs and is scanning:
We have noticed that on Android 9 when the screen is turned off no more Scan_Result events are fired, and when the screen is turn back on the scan results resume.
We were using the standard Ble method that Erel provided, https://www.b4x.com/android/forum/threads/ble-2-bluetooth-low-energy.59937/#content
We switched to the above code example to see if it made a difference, the result was the same. It functioned fine up to Android 8.
Regards
John.
We are working with these devices, https://store.kontakt.io/next-generation/43-asset-tag-s18-3.html.
We have a service that runs and is scanning:
B4X:
#Region Service Attributes
#StartAtBoot: False
#End Region
Sub Process_Globals
'These global variables will be declared once when the application starts.
'These variables can be accessed from all modules.
Private manager As BleManager2
Private currentStateText As String = "UNKNOWN"
Private currentState As Int
Private scanning As Boolean
Private bc As ByteConverter
Private const TIME_TO_LIVE_SECONDS As Int = 30
Private Timer1 As Timer
Private rp As RuntimePermissions
Private ManagerJO As JavaObject
Private Adapter As JavaObject
Private Scanner As JavaObject
Private ScanCallback As JavaObject
End Sub
Sub Service_Create
manager.Initialize("manager")
ManagerJO = manager
Adapter = ManagerJO.GetField("blueAdapter")
Scanner = Adapter.RunMethod("getBluetoothLeScanner", Null)
ScanCallback.InitializeNewInstance(Application.PackageName & ".svc_ble_sos_le$MyScanCallback", Null)
Timer1.Initialize("hook",5000)
End Sub
Sub Service_Start (StartingIntent As Intent)
Timer1.Enabled = True
StartScan_le
End Sub
Sub Service_Destroy
StopScanWithLeScanner
Timer1.Enabled = False
End Sub
Sub hook_tick
mod_functions.writelog("hook_tick() Still Running")
End Sub
Sub Manager_StateChanged (State As Int)
Select State
Case manager.STATE_POWERED_OFF
currentStateText = "POWERED OFF"
Case manager.STATE_POWERED_ON
currentStateText = "POWERED ON"
Case manager.STATE_UNSUPPORTED
currentStateText = "UNSUPPORTED"
End Select
currentState = State
End Sub
Sub Manager_DeviceFound (Name As String, Id As String, AdvertisingData As Map, RSSI As Double)
End Sub
' // based on this answer: http://stackoverflow.com/questions/20416218/understanding-ibeacon-distancing
Private Sub CalculateDistance(tx As Int, rssi As Double) As Double
If rssi = 0 Then Return -1
Dim ratio As Double = rssi / tx
If ratio < 1 Then
Return Power(ratio, 10)
Else
Return 0.89976 * Power(ratio, 7.7095) + 0.111
End If
End Sub
#region "LE Scanner"
Public Sub StartScan_le
If manager.State <> manager.STATE_POWERED_ON Then
Log("Not powered on.")
Else If rp.Check(rp.PERMISSION_ACCESS_COARSE_LOCATION) = False Then
Log("No location permission.")
Else
ScanWithLeScanner
End If
End Sub
Private Sub Scan_Result (Result As Object)
Dim ScanResult As JavaObject = Result
Dim device As JavaObject = ScanResult.RunMethod("getDevice", Null)
Dim address As String = device.RunMethod("getAddress", Null)
ManagerJO.GetFieldJO("devices").RunMethod("put", Array(address, device))
Dim name As String
Dim o As Object = device.RunMethod("getName", Null)
If o = Null Then name = "" Else name = o
Dim ScanRecord As JavaObject = ScanResult.RunMethod("getScanRecord", Null)
'Log(ScanRecord) 'you can extend the code to access the data.
'https://developer.android.com/reference/android/bluetooth/le/ScanRecord
Dim rssi As Double = ScanResult.RunMethod("getRssi", Null)
log("svc_ble_sos_le() Scan_Result > name : " & name & ", rssi : " & rssi & ", " & address)
' // not called yet as screen off issue
' Manager_DeviceFound(name, address, CreateMap(), rssi)
End Sub
Private Sub ScanWithLeScanner
Dim ScanSettingsStatic As JavaObject
ScanSettingsStatic.InitializeStatic("android.bluetooth.le.ScanSettings")
Dim ScanSettingsBuilder As JavaObject
ScanSettingsBuilder.InitializeNewInstance("android.bluetooth.le.ScanSettings.Builder", Null)
'https://developer.android.com/reference/android/bluetooth/le/ScanSettings.Builder
ScanSettingsBuilder.RunMethod("setScanMode", Array(ScanSettingsStatic.GetField("SCAN_MODE_LOW_POWER")))
Scanner.RunMethod("startScan", Array(Null, ScanSettingsBuilder.RunMethod("build", Null), ScanCallback))
End Sub
Private Sub StopScanWithLeScanner
Scanner.RunMethod("stopScan", Array(ScanCallback))
End Sub
#End Region
#if Java
import android.bluetooth.le.*;
public static class MyScanCallback extends ScanCallback {
public void onScanResult(int callbackType, ScanResult result) {
processBA.raiseEvent(this, "scan_result", result);
}
/**
* Callback when scan could not be started.
*
* @param errorCode Error code (one of SCAN_FAILED_*) for scan failure.
*/
public void onScanFailed(int errorCode) {
BA.Log("Error: " + errorCode);
}
}
#End IfWe have noticed that on Android 9 when the screen is turned off no more Scan_Result events are fired, and when the screen is turn back on the scan results resume.
We were using the standard Ble method that Erel provided, https://www.b4x.com/android/forum/threads/ble-2-bluetooth-low-energy.59937/#content
We switched to the above code example to see if it made a difference, the result was the same. It functioned fine up to Android 8.
Regards
John.
