belongs to Maven artifact com.android.support:support-core-utils:28.0.0-alpha1
Deprecated since version 26.1.0
WakefulBroadcastReceiver
public
abstract
class
WakefulBroadcastReceiver
extends BroadcastReceiver
| java.lang.Object | ||
| ↳ | android.content.BroadcastReceiver | |
| ↳ | android.support.v4.content.WakefulBroadcastReceiver | |
This class was deprecated
in API level 26.1.0.
As of Android O, background check
restrictions make this class no longer generally useful. (It is generally not safe to
start a service from the receipt of a broadcast, because you don't have any guarantees
that your app is in the foreground at this point and thus allowed to do so.) Instead,
developers should use android.app.job.JobScheduler to schedule a job, and this
does not require that the app hold a wake lock while doing so (the system will take
care of holding a wake lock for the job).
This helper is for an old pattern of implementing a BroadcastReceiver
that receives a device wakeup event and then passes the work off
to a Service, while ensuring that the
device does not go back to sleep during the transition.
This class takes care of creating and managing a partial wake lock
for you; you must request the WAKE_LOCK
permission to use it.
Wakelocks held by this class are reported to tools as
"androidx.core:wake:<component-name>".
Example
A WakefulBroadcastReceiver uses the method
startWakefulService()
to start the service that does the work. This method is comparable to
startService(), except that
the WakefulBroadcastReceiver is holding a wake lock when the service
starts. The intent that is passed with
startWakefulService()
holds an extra identifying the wake lock.
import android.content.Context;
import android.content.Intent;
import android.os.SystemClock;
import android.support.v4.content.WakefulBroadcastReceiver;
import android.util.Log;
public class SimpleWakefulReceiver extends WakefulBroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
// This is the Intent to deliver to our service.
Intent service = new Intent(context, SimpleWakefulService.class);
// Start the service, keeping the device awake while it is launching.
Log.i("SimpleWakefulReceiver", "Starting service @ " + SystemClock.elapsedRealtime());
startWakefulService(context, service);
}
}The service (in this example, an IntentService) does
some work. When it is finished, it releases the wake lock by calling
completeWakefulIntent(intent). The intent it passes as a parameter
is the same intent that the WakefulBroadcastReceiver originally
passed in.
import android.app.IntentService;
import android.content.Intent;
import android.os.SystemClock;
import android.util.Log;
public class SimpleWakefulService extends IntentService {
public SimpleWakefulService() {
super("SimpleWakefulService");
}
@Override
protected void onHandleIntent(Intent intent) {
// At this point SimpleWakefulReceiver is still holding a wake lock
// for us. We can do whatever we need to here and then tell it that
// it can release the wakelock. This sample just does some slow work,
// but more complicated implementations could take their own wake
// lock here before releasing the receiver's.
//
// Note that when using this approach you should be aware that if your
// service gets killed and restarted while in the middle of such work
// (so the Intent gets re-delivered to perform the work again), it will
// at that point no longer be holding a wake lock since we are depending
// on SimpleWakefulReceiver to that for us. If this is a concern, you can
// acquire a separate wake lock here.
for (int i=0; i<5; i++) {
Log.i("SimpleWakefulReceiver", "Running service " + (i+1)
+ "/5 @ " + SystemClock.elapsedRealtime());
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
}
}
Log.i("SimpleWakefulReceiver", "Completed service @ " + SystemClock.elapsedRealtime());
SimpleWakefulReceiver.completeWakefulIntent(intent);
}
}Summary
Public constructors | |
|---|---|
WakefulBroadcastReceiver()
|
|
Public methods | |
|---|---|
static
boolean
|
completeWakefulIntent(Intent intent)
Finish the execution from a previous |
static
ComponentName
|
startWakefulService(Context context, Intent intent)
Do a |
Inherited methods | |
|---|---|
android.content.BroadcastReceiver
| |
java.lang.Object
| |
Public constructors
Public methods
completeWakefulIntent
boolean completeWakefulIntent (Intent intent)
Finish the execution from a previous startWakefulService(Context, Intent). Any wake lock
that was being held will now be released.
| Parameters | |
|---|---|
intent |
Intent: The Intent as originally generated by startWakefulService(Context, Intent). |
| Returns | |
|---|---|
boolean |
Returns true if the intent is associated with a wake lock that is now released; returns false if there was no wake lock specified for it. |
startWakefulService
ComponentName startWakefulService (Context context, Intent intent)
Do a Context.startService, but holding a wake lock while the service starts.
This will modify the Intent to hold an extra identifying the wake lock;
when the service receives it in Service.onStartCommand, it should pass back the Intent it receives there to
completeWakefulIntent(android.content.Intent) in order to release
the wake lock.
| Parameters | |
|---|---|
context |
Context: The Context in which it operate. |
intent |
Intent: The Intent with which to start the service, as per
Context.startService.
|
| Returns | |
|---|---|
ComponentName |
|
Interfaces
Classes