could not find callback wrapper on Android

[azakost]

Error occur when calling startPeripheralScan() function.

D/BluetoothLeScanner( 5266): could not find callback wrapper E/flutter ( 5266): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: BleError (Error code: 600, ATT error code: null, iOS error code: null, Android error code: null, reason: Scan failed because application registration failed (code 6), internal message: null, device ID: null, service UUID: null, characteristic UUID: null, descriptor UUID: null)

Same thing with an example app. Sometimes it works, but mostly throwing this kind of error.

Any ideas how to fix this?

[ChrisMarxDev]

I am currently struggling with the same error on Android. Some fixes that I encountered while searching for a solution were:

• Make sure that the BleManager is setup correctly

  BleManager bleManager = BleManager();
  await bleManager.createClient();

• Make sure that all relevant bluetooth and location permissions are declared in the AndroidManifest.xml:

  <uses-permission android:name="android.permission.BLUETOOTH" /> 
  <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
  <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
  <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

I am still experiencing this error, but maybe these fixes help you.

[mikolak]

Have you requested the necessary runtime permission? From Android 10 you need ACCESS_FINE_LOCATION.