foregroundService in android java

Question

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        startForegroundService(new Intent(this,service.class));
    }

Here's the source code. As we can see, startForegroundService works above 25 API level. But, my question is how Facebook, Instagram and WhatsApp use it in every API level?

Answer 1

If you are using androidx (which IMO you should be), you can use ContextCompat.startForegroundServce which works on all API versions

If not, you can check the API version before you call:

if (Build.VERSION.SDK_INT >= 26) {
    context.startForegroundService(intent);
} else {
    context.startService(intent);
}

Note that Service.startForeground is available since API 5, which means your service can be foreground without calling startForegroundService on those API versions.

If you are curious why that changed in API 26, here is a quote from the documentation:

Prior to Android 8.0, the usual way to create a foreground service was to create a background service, then promote that service to the foreground. With Android 8.0, there is a complication; the system doesn't allow a background app to create a background service. For this reason, Android 8.0 introduces the new method startForegroundService() to start a new service in the foreground. After the system has created the service, the app has five seconds to call the service's startForeground() method to show the new service's user-visible notification. If the app does not call startForeground() within the time limit, the system stops the service and declares the app to be ANR.