onReceive

onReceive is a callback method in Android's BroadcastReceiver class. It is invoked by the Android framework when a broadcast that matches the receiver’s intent filters is delivered, and it receives the Intent object carrying the action, data, and extras of the broadcast.

The canonical signature is public void onReceive(Context context, Intent intent). The context parameter provides access to application resources and services, while the intent carries information about what happened, including the action via getAction() and any accompanying data or extras.

Execution and lifecycle considerations: onReceive runs on the main thread of the process. It should complete quickly and not perform long-running operations. If substantial work is needed, the receiver should start a Service or delegate work to components such as WorkManager. After onReceive finishes, the system may terminate the process, so the method should not rely on long-lived state or background execution within the callback itself.

Registration and scope: A BroadcastReceiver can be declared in the app’s manifest or registered dynamically at runtime. Manifest-registered receivers can respond to broadcasts even when the app is not running, while dynamically registered receivers exist only while the registering component is active. Since the introduction of background execution limits, many implicit broadcasts registered in the manifest are restricted on modern versions of Android, encouraging dynamic registration or alternative approaches.

Usage notes: Inside onReceive, developers typically inspect the action and extract extras from the intent to determine appropriate behavior. For longer tasks, it is common to start a service or schedule work using WorkManager, and to consider security measures such as validating the sender and intent data.

See also BroadcastReceiver, Intent, IntentFilter, Service, WorkManager.