permanent BroadcastReceiver?

Question

I use a broadcastReceiver to trigger alarms in an app that has an alarm clock feature. The class is currently very simple

public class MyReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
    Intent scheduledIntent = new Intent(context, AlarmUp.class);
    scheduledIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    context.startActivity(scheduledIntent);

}}

The problem is that it gets cancelled in the case of device reboot, so the alarm doesn't trigger. Is there any way to get the receiver to automatically continue after a reboot? Thx

Answer 1

Is there any way to get the receiver to automatically continue after a reboot?

Unfortunately no. The system destroys all pending intents when the phone is turned off.

To solve your problem, you should filter on the android.intent.action.BOOT_COMPLETED to have a BroadcastReceiver called on device boot up. Then you can re-schedule all the needed alarms.

Something like this in your manifest :

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

<receiver
    android:name=".broadcasts.InitReceiver"
    android:exported="false" >
    <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED" />
        <action android:name="android.intent.action.TIME_SET" />
        <action android:name="android.intent.action.TIMEZONE_CHANGED" />
    </intent-filter>
</receiver>

You can notice that there is also TIME_SET and TIMEZONE_CHANGED as you probably want your alarms to work even is the user is traveling from a timezone to another.

And something like this for the broadcast.

public class YourBroadcastReceiverName extends BroadcastReceiver {

    private AlarmManagerFacade alarmManager;

    @Override
    public void onReceive(Context context, Intent intent) {

        // Retreive data related to alarms
        Cursor cursor = context.getContentResolver().query(Alarm.CONTENT_URI, null,
                Alarm.COLUMN_ACTIVE + " = ? ",
                new String[] { String.valueOf(1) }, "");

        if (cursor.moveToFirst()) {

            // Schedule all the active alarms.
            alarmManager = new AlarmManagerFacade(context);
            do {
                // TODO : Schedule alarm according to data in cursor.
            } while (cursor.moveToNext());
        }
        cursor.close();
    }
}

( This code is coming from one of my app. Some object may not be available in the Android SDK. )

In order to be able to re schedule all the alarms, you need to have them stored somewhere.

You can write your own ContentProvider for example.

• It works well with other android components thanks to the CursorAdapter widget.
• It is not the easiest solution but it's the way to go if you want to follow android guidelines.

There may be other simpler alternative to store your alarms, like using SharedPreferences.

• It's easy to use.
• But you will need to hack around to store multiple alarms in a friendly manner.

One last alternative is that you can create an object containing the information, serialize it and store it as a file on the SD Card.

• It's ugly and not flexible.
• But it not that hard to implement ...

If you want to have a closer look to the different storage options you can read about it in the docs here : http://developer.android.com/guide/topics/data/data-storage.html

I hope all this help you. :)

Answer 2

Edit your manifest file,

<receiver android:name=".RecieverName" 
             android:enabled="true" 
             android:exported="false">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED"/>
            </intent-filter>
        </receiver>

It will automatically start on device reboot.

also declare the permission for it,

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>