/ble-scan-issue

Primary LanguageKotlin

Android BLE scan issue

Simple app to demonstrate issue with BLE background scanner available for Android 8+ when using CALLBACK_TYPE_FIRST_MATCH.

Problem

When there are 2 apps starting background scanner with PendingIntent callback for the same BLE device with CALLBACK_TYPE_FIRST_MATCH, filtered by manufacturer data, then only the second app that started scanner will receive callback twice.

Prerequisites

To reproduce that you will need two devices, one with apps installed and second acting as a BLE advertiser. For the BLE advertising you can install e.g. nRF Connect app and set up Advertiser there with Advertising Data:

Manufacturer Data:
Company ID: 0x1111
Data: 0x00

nRF Connect

Steps to reproduce

  • Install 2 variants of the app on one device (e.g. debug and alpha)
  • Press Start Background Scan first in debug app, and then in alpha app - it will start background scanner for the same BLE device
  • On your second device start BLE Advertiser
  • Observe that on your first device, alpha app received the scan callback twice, debug didn’t get any callbacks (you can filter by BleScanIssue tag in Logcat)