Creating a foreground service

Creating a foreground service

Things you'll need

• For Android 14+, To choose a foreground service type from android docs

Steps

1. Specify service in buildozer.spec Properly

According to p4a docs we need to specify it's going to be a foreground service in buildozer.spec

services = Mydownloader:./services/mydownloader.py:foreground

# my package for notifications
requirements = python3, kivy, pyjnius, android-notify

# Add permission for notifications
android.permissions = POST_NOTIFICATIONS

2. Automate adding Service Type in AndroidManifest.xml

To automate this process from your buildozer.spec by passing in an argument for p4a.hook

p4a.hook = p4a/hook.py

You have to use foreground service type fitting your use-case.

For this example I'm using dataSync which is for download|uploads.

Programmatically found my service and added a type argument:

# p4a/hook.py
from pathlib import Path
from pythonforandroid.toolchain import ToolchainCL

def after_apk_build(toolchain: ToolchainCL):
    manifest_file = Path(toolchain._dist.dist_dir) / "src" / "main" / "AndroidManifest.xml"
    text = manifest_file.read_text(encoding="utf-8")

    # Change these three lines to fit your use-case 
    package = "org.laner.lan_ft" # Find value in your buildozer.spec "package.domain.package.name"
    service_name="Mydownloader"
    foreground_type="dataSync"
    target = f'android:name="{package}.Service{service_name.capitalize()}"'

    # Inject foregroundServiceType
    pos = text.find(target)
    if pos != -1:
        end = text.find("/>", pos)
        text = (
                    text[:end] +
                    ' android:foregroundServiceType="{foreground_type}"' +
                    text[end:]
                )
        print("Successfully Added foregroundServiceType to ServiceMydownloader")

    text = text.replace("</application>", f"{receiver_xml}\n</application>")
    print("Successfully added Receiver")

    # Write back the final manifest
    manifest_file.write_text(text, encoding="utf-8")
    print("Manifest update completed",text)

3. Foreground Permissions

• You must add FOREGROUND_SERVICE and POST_NOTIFICATIONS
• According to your foreground type you might have an additional permission in my case only FOREGROUND_SERVICE_DATA_SYNC

android.permissions = FOREGROUND_SERVICE, POST_NOTIFICATIONS, FOREGROUND_SERVICE_DATA_SYNC

4. Start your service then promote it to Foreground Service

# main.py
def start_service():
    from android import mActivity
    from jnius import autoclass

    context = mActivity.getApplicationContext()
    service_name="Mydownloader"
    service_class=autoclass(context.getPackageName() + '.Service' + service_name.capitalize())
    service.start(self.mActivity, "port number")

Finally in your service file Promote it to a foreground service

Reduced boilerplate with android-notify

# ./services/mydownloader.py
print("Entered Service File...")
import time,os
from jnius import autoclass
from android_notify import Notification

# get and see parameter from ui 
Notification(title = os.environ.get('PYTHON_SERVICE_ARGUMENT', 'no arg')).send()

BuildVersion = autoclass("android.os.Build$VERSION")
ServiceInfo = autoclass("android.content.pm.ServiceInfo")
PythonService = autoclass('org.kivy.android.PythonService')

service = PythonService.mService
foreground_type= ServiceInfo.FOREGROUND_SERVICE_TYPE_DATA_SYNC if BuildVersion.SDK_INT >= 30 else 0
fmt = lambda s: f"{int(s//3600)}h {int((s%3600)//60)}m {int(s%60)}s"


n=Notification(title="Foreground Service Active", message="This service is running in the foreground")
builder=n.start_building() # not using .send() allowing .startForeground() to send initial notification 
service.startForeground(n.id, builder.build(), foreground_type)
service.setAutoRestartService(True)  # auto-restart if killed


print("Foreground Service is alive. Entering main loop...")
n1 = Notification(title="Running for 0h 0m 0s")
n1.send()

start = time.time()
while True:
    elapsed = time.time() - start
    n1.updateTitle(f"Running for {fmt(elapsed)}")
    time.sleep(2)