I am trying to clarify the difference between a Broadcast Receiver and Service in android.
I understand that an activity can start a service by calling startService
with an intent.
A broadcast receiver can be registered in code or the manifest and can be called with sendBroadcast
.
When would you use one vs the other?
I understand that multiple broadcast receiver's can be listening for the same intent and this is NOT the case with a service.
A Service receives intents that were sent specifically to your application, just like an Activity. A Broadcast Receiver receives intents that were broadcast system-wide to all apps installed on the device.
A Broadcast Receiver is a system listener (events from the OS), or listener to other apps. Service is what you use internally in your App.
Broadcast in android is the system-wide events that can occur when the device starts, when a message is received on the device or when incoming calls are received, or when a device goes to airplane mode, etc. Broadcast Receivers are used to respond to these system-wide events.
There are two types of broadcast receivers: Static receivers, which you register in the Android manifest file. Dynamic receivers, which you register using a context.
Services are meant to perform an action in the background for some period of time, regardless of what the user is doing in foreground (the user could be switching between activities). A good example would be a music player service - the user starts playing music through a music player app but when they exit the app the music keeps playing.
Services are also useful to provide/manage common access to a resource across multiple applications. This is often used for system resources, such as sensors.
Broadcast receivers are meant to respond to an intent (usually one sent by a service or a system event), do something, and be done. An example here might be the user touches an NFC-enabled phone to a tag, the system creates an intent for it, and a registered receiver handles it to change some settings (change volume, turn on bluetooth, etc).
When an intent is broadcast via sendBroadcast, it will be sent to all receivers that have matching intent filters. However, it is important to note that in API26+ most receivers registered in the manifest are no longer invoked in such situations, see the Google docs for more information.
Example 1: Suppose you want to expose a function (to be available from any application that wants to use it) that asks a website to calculate degrees of separation from Kevin Bacon.
Note that this example is "do something and return", as opposed to perform a long-running background operation.
You could implement this in several ways:
Create a library project that all users compile into their application.
Create a broadcast receiver to handle each request.
Create a service to handle each request
Example 2: You want to perform some data analysis to find some patterns in your data
Background Thread If all processing should happen while the user is in the same application and on the same Activity, a background thread (or better, a coroutine) would be a good approach
Service If you want to allow the user to exit the application while the processing is being performed (and notify them of the results later), or allow them to progress through multiple activities in the same application while the processing is being performed, a Service would be a better approach
Broadcast Receiver
Quoting Dianne Hackborn on the Android Developers blog:
When handling a broadcast, the application is given a fixed set of time (currently 10 seconds) in which to do its work. If it doesn't complete in that time, the application is considered to be misbehaving, and its process immediately tossed into the background state to be killed for memory if needed.
Broadcast receivers are limited by maximum amount of time(10 seconds generally), they have to finish.
Service
If your action takes some longer time (connecting to the internet can take some).More preferrably as the run at background. You definitely should call a service from the receiver or Activity for this purpose. They are last to be killed by android Operating System.
Conclusion:
Generally speaking all the work (fetching, parsing, caching, updating database) which is important to your application should be moved to Service
as they are long lived on Android. As you've almost considered that all the social networking sites have there STICKY_SERVICES
which does all troublesome work.
BroadcastReceiver
are mostly used to start the service. It generally depends upon application. Most of the application uses ConnectivityManager
to broadcast whenever network is UP OR DOWN. With the help of these Service
are started by BroadcastReceiver
.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With