Using Bumble with Android is not about running the Bumble stack on the Android OS itself, but rather using Bumble with the Bluetooth support of the Android emulator.
The two main use cases are:
!!! warning Bluetooth support in the Android emulator is a recent feature that may still be evolving. The information contained here be somewhat out of sync with the version of the emulator you are using. You will need version 31.3.8.0 or later.
The Android emulator supports Bluetooth in two ways: either by exposing virtual Bluetooth controllers to which you can connect a virtual Bluetooth host stack, or by exposing an way to connect your own virtual controller to the Android Bluetooth stack via a virtual HCI interface. Both ways are controlled via gRPC requests to the Android emulator.
If the version of the emulator you are running does not yet support enabling Bluetooth support by default or automatically, you must launch the emulator from the command line.
!!! tip For details on how to launch the Android emulator from the command line, visit this Android Studio user guide page
The -grpc <port> command line option may be used to select a gRPC port other than the default.
The Android emulator's virtual Bluetooth controller is called Root Canal. Multiple instances of Root Canal virtual controllers can be instantiated, they communicate link layer packets between them, thus creating a virtual radio network. Configuring a Bumble Device instance to use Root Canal as a virtual controller allows that virtual device to communicate with the Android Bluetooth stack, and through it with Android applications as well as system-managed profiles. To connect a Bumble host stack to a Root Canal virtual controller instance, use the bumble android-emulator transport in host mode (the default).
!!! example “Run the example GATT server connected to the emulator” shell $ python run_gatt_server.py device1.json android-emulator
This is an advanced use case, which may not be officially supported, but should work in recent versions of the emulator. You will likely need to start the emulator from the command line, in order to specify the -forward-vhci option (unless the emulator offers a way to control that feature from a user/ui menu).
!!! example “Launch the emulator with VHCI forwarding” In this example, we launch an emulator AVD named “Tiramisu” shell $ emulator -forward-vhci -avd Tiramisu
!!! tip Attaching a virtual controller use the VHCI forwarder while the Android Bluetooth stack is running isn't supported. So you need to disable Bluetooth in your running Android guest before attaching the virtual controller, then re-enable it once attached.
To connect a virtual controller to the Android Bluetooth stack, use the bumble android-emulator transport in controller mode. For example, using the default gRPC port, the transport name would be: android-emulator:mode=controller.
!!! example “Connect the Android emulator to the first USB Bluetooth dongle, using the hci_bridge application” shell $ bumble-hci-bridge android-emulator:mode=controller usb:0
The show application that's included with Bumble can be used to parse and pretty-print the HCI packets from an Android HCI “snoop log” (see this page for details on how to obtain HCI snoop logs from an Android device). Use the --format snoop option to specify that the file is in that specific format.
!!! example “Analyze an Android HCI snoop log file” shell $ bumble-show --format snoop btsnoop_hci.log