python-for-android backend

.github/workflows/build_and_test.yml

@@ -7,7 +7,7 @@ on:
         branches: [ master, develop ]
 
 jobs:
-    build_linux:
+    build_desktop:
         name: "Build and test"
         runs-on: ${{ matrix.os }}
         strategy:
@@ -36,3 +36,27 @@ jobs:
                     path: junit/test-results-${{ matrix.os }}-${{ matrix.python-version }}.xml
                 # Use always() to always run this step to publish test results when there are test failures
                 if: ${{ always() }}
+    build_android:
+        name: "Build Android"
+        runs-on: ubuntu-20.04
+        steps:
+            -   uses: actions/checkout@v2
+            -   name: Upgrade pip. setuptools and wheel
+                run: python -m pip install --upgrade pip setuptools wheel
+            -   name: Install dependencies
+                run: pip install buildozer cython
+            -   name: Cache buildozer files
+                uses: actions/cache@v2
+                id: buildozer-cache
+                with:
+                    path: |
+                        ~/.buildozer
+                        examples/kivy/.buildozer
+                    key: build-cache-buildozer
+            -   name: Clean bleak recipe for cache
+                if: steps.buildozer-cache.outputs.cache-hit == 'true'
+                working-directory: examples/kivy
+                run: buildozer android p4a -- clean-recipe-build --local-recipes $(pwd)/../../bleak/backends/p4android/recipes bleak
+            -   name: Build Kivy example
+                working-directory: examples/kivy
+                run: buildozer android debug

CHANGELOG.rst

@@ -17,6 +17,7 @@ Added
 * Added ``register_uuids()`` to augment the uuid-to-description mapping.
 * Added support for Python 3.10.
 * Added ``force_indicate`` keyword argument for WinRT backend client's ``start_notify`` method. Fixes #526.
+* Added python-for-android backend.
 
 Changed
 -------

README.rst

@@ -44,6 +44,7 @@ Features
 * Supports Windows 10, version 16299 (Fall Creators Update) or greater
 * Supports Linux distributions with BlueZ >= 5.43
 * OS X/macOS support via Core Bluetooth API, from at least OS X version 10.11
+* Android backend compatible with python-for-android
 
 Bleak supports reading, writing and getting notifications from
 GATT servers, as well as a function for discovering BLE devices.

bleak/__init__.py

@@ -30,6 +30,13 @@
 
 if _on_rtd:
     pass
+elif os.environ.get("P4A_BOOTSTRAP") is not None:
+    from bleak.backends.p4android.scanner import (
+        BleakScannerP4Android as BleakScanner,
+    )  # noqa: F401
+    from bleak.backends.p4android.client import (
+        BleakClientP4Android as BleakClient,
+    )  # noqa: F401
 elif platform.system() == "Linux":
     if not _on_ci and not check_bluez_version(5, 43):
         raise BleakError("Bleak requires BlueZ >= 5.43.")

bleak/backends/p4android/characteristic.py

@@ -0,0 +1,90 @@
+from uuid import UUID
+from typing import Union, List
+
+from bleak.backends.characteristic import BleakGATTCharacteristic
+from bleak.backends.descriptor import BleakGATTDescriptor
+from bleak.exc import BleakError
+
+
+from . import defs
+
+
+class BleakGATTCharacteristicP4Android(BleakGATTCharacteristic):
+    """GATT Characteristic implementation for the python-for-android backend"""
+
+    def __init__(self, java, service_uuid: str, service_handle: int):
+        super(BleakGATTCharacteristicP4Android, self).__init__(java)
+        self.__uuid = self.obj.getUuid().toString()
+        self.__handle = self.obj.getInstanceId()
+        self.__service_uuid = service_uuid
+        self.__service_handle = service_handle
+        self.__descriptors = []
+        self.__notification_descriptor = None
+
+        self.__properties = [
+            name
+            for flag, name in defs.CHARACTERISTIC_PROPERTY_DBUS_NAMES.items()
+            if flag & self.obj.getProperties()
+        ]
+
+    @property
+    def service_uuid(self) -> str:
+        """The uuid of the Service containing this characteristic"""
+        return self.__service_uuid
+
+    @property
+    def service_handle(self) -> int:
+        """The integer handle of the Service containing this characteristic"""
+        return int(self.__service_handle)
+
+    @property
+    def handle(self) -> int:
+        """The handle of this characteristic"""
+        return self.__handle
+
+    @property
+    def uuid(self) -> str:
+        """The uuid of this characteristic"""
+        return self.__uuid
+
+    @property
+    def properties(self) -> List:
+        """Properties of this characteristic"""
+        return self.__properties
+
+    @property
+    def descriptors(self) -> List:
+        """List of descriptors for this service"""
+        return self.__descriptors
+
+    def get_descriptor(
+        self, specifier: Union[str, UUID]
+    ) -> Union[BleakGATTDescriptor, None]:
+        """Get a descriptor by UUID (str or uuid.UUID)"""
+        if isinstance(specifier, int):
+            raise BleakError(
+                "The Android Bluetooth API does not provide access to descriptor handles."
+            )
+
+        matches = [
+            descriptor
+            for descriptor in self.descriptors
+            if descriptor.uuid == str(specifier)
+        ]
+        if len(matches) == 0:
+            return None
+        return matches[0]
+
+    def add_descriptor(self, descriptor: BleakGATTDescriptor):
+        """Add a :py:class:`~BleakGATTDescriptor` to the characteristic.
+
+        Should not be used by end user, but rather by `bleak` itself.
+        """
+        self.__descriptors.append(descriptor)
+        if descriptor.uuid == defs.CLIENT_CHARACTERISTIC_CONFIGURATION_UUID:
+            self.__notification_descriptor = descriptor
+
+    @property
+    def notification_descriptor(self) -> BleakGATTDescriptor:
+        """The notification descriptor.  Mostly needed by `bleak`, not by end user"""
+        return self.__notification_descriptor