Develop Reference

How to avoid broadcast from being wasted when receiver is registered inside activity?

I have a service which will broadcast a message to broadcast receiver which is registered in some activity. The activity might be running or not. If it's open then broadcast will be received. But if not, the broadcast will be wasted. Is there a way to avoid this broadcast from being wasted without adding the broadcast inside manifest?

Consider to start/stop that service based on Activity's lifecycle, when Activity is created (onCreate()) start that service. When Activity is destroyed (onDestroy()) stop the service so you avoid "waste" those messages and even have a service running.

1- Create an inner class in your activity that extends BroadcastReceiver.
2- Create an object of your receiver and an intent filter.
3- Override onResume and registerReceiver(receiver, intentFilter);
4- Override onPause and unregisterReceiver(receiver);
Take a look at this answer. you dont have to add it in the manifest.
answer here

Broadcast receiver works only when device reboot android

Hi I am developing android application in which I am defining one broadcast receiver.I am calling receiver from my activity. I am defining broadcast receiver like this :
public class MyScheduleReceiver extends BroadcastReceiver {
private static final long REPEAT_TIME = 100 * 5;
#Override
public void onReceive(Context context, Intent intent) {
Log.i("RRRRRRRRRRRRRRRRRRRRRRRR", "on receive");
}
}
In android manifest file I am defining like this:
<receiver android:name="abc.xyz.MyScheduleReceiver" >
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
and in main activity I am calling my broadcast receiver like this :
//in activity oncreate
startService(new Intent(this, MyScheduleReceiver.class));
My problem is that when call start service it's not starting my service actually. But when i restart my device it start my service because I gave intent filter "BOOT_COMPLETED". what I wanted to do actually when i call start service my service must be start,
Am I doing something wrong. How to solve this problem?

Actual what happens here is that you can staring a broadcast receiver while starting the activity and this broadcast receiver starts listening BOOT_COMPLEATED is happening or not. When this happens it comes to onreceive . If you need to start a process doing in background you can use a a Service insted of BroadcastReciever. BroadcastRecievers are used to listen for some events to happen.Go through this, it will help you
Services
BroadcastReceiver

You're either confused, or you aren't wording your question well. What you have in your manifest (and how Android works generally) is that when BOOT_COMPLETED occurs, it will call that BroadcastReceiver you defined. It will not automatically start an activity or service. If you want to do that, you need to call startService or startActivity in your onReceive function of the receiver.
You do not start BroadcastReceivers. You start services, which are long term background processes. You register BroadcastReceivers to be informed of special events (like BOOT_COMPLETED). When one of the events you registered for occurs, it will create an instance of that class and call its onReceive.
Hopefully that clears things up. If not, I suggest you reread some tutorials on services and broadcast receivers, you seem to have the two confused.

startService call would only start a Service. MyScheduleReceiver here is a braodcast receiver. To trigger broadcast receivers, you generally have to send broadcasts and not call the startService.

to start broadcasts you need to send broadcasts not startService()
add this instead of startService(new Intent(this, MyScheduleReceiver.class));
Intent intent = new Intent();
intent.setAction("pakagename.MyScheduleReceiver");
sendBroadcast(intent);
I hope it helps.

Start Activity for result in a Broadcast Receiver?

I have managed to get an Activity to start from my onReceive() methdod, but I really need to do a startActivityForResult();.
Is there any way I could do this?
On a side note, how would I make my app become a 'camera' app, as in it would appear when an app started the intent to take a picture?

The important thing to know about broadcast receivers is that you should not add long running processes in it, because after something like 5 seconds your app will crash.
The best thing to do in your case is to intent to other Activity from your broadcast receiver, and from that activity use startActivityForResult(), get the picture and continue from there...

startActivityForResult can only be called from an Activity since it is defined in the Activity class and require instance of activity.
You can only call startAcivity() from broadcast receiver since in onRecieve() you only have access to generic context object and it does not have startActivityForResult method defined in the class..

Finish two activities on receive the same broadcast

I have a BroadcastReceiver which handles System Broadcasts like AC Connected and disconnected. The BroadcastReceiver receives POWER_CONNECTED and starts an Activity "MainActivity", which unlocks KeyGuard and acquires WakeLock. In the onCreate and in onResume I register dynamically a BroadcastReceiver to listen on POWER_DISCONNECTED.
The "MainActivity" starts a second "VideoPlayer Activity", which also register a BroadcastReceiver listening on POWER_DISCONNECTED.
When I send the ACTION_POWER_DISCONNECT over adb I see through LogCat that the "MainActivity" stops first. Why?
How can I handle that the "VideoPlayerActivity" finishes first?
Thanks

Look here (http://developer.android.com/reference/android/content/BroadcastReceiver.html):
Normal broadcasts (sent with Context.sendBroadcast) are completely asynchronous. All receivers of the broadcast are run in an undefined order, often at the same time. This is more efficient, but means that receivers cannot use the result or abort APIs included here.
You can't guarantee that VideoPlayerActivity will receive.
I would recommend to create a separate BroadcastReceiver (which isn't part of activities). And in this broadcast receiver do something like this:
videoPlayerActivity.finish();
mainActivity.finish();
Sure, you need to initialize both of these variables in onCreate or onResume of your activities.

Actually you Registered the Broadcast Receiver in your main activity so its passing the context of main activity in the BroadcastReceiver so i will able to finish only that activity.
So lets screw up this what you need to do just write these lines of code in the onReceive() of Power Disconnected action receiver:
public void onReceive(Context context, Intent intent) {
Intent startMain = new Intent(Intent.ACTION_MAIN);
startMain.addCategory(Intent.CATEGORY_HOME);
startMain.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(startMain);
}
Enjoy

Using BroadcastReceiver

I want to know whether an app can be a BroadcastReceiver and sender? Please expain with an example.

Application can't be a BroadcastReceiver. BroadcastReceiver is an application component. But answer to your question is yes: you can send broadcasts from one component and receive it in another.
For ex. in activity:
Intent intent = new Intent(...);
sendBroadcast(intent);
In receiver:
#Override
public void onReceive(Context context, Intent intent) {
// here is your intent
}

Yes, it can. An example can be found here.

If by app you mean activity, so yes you can but you will have to embed your BroadcastReceiver in your activity and register/unregister it yourself. That way, you just need to add your activity as Activity in the Manifest and you activity will be able to receive a broadcast and send broadcast as well.
I m not too sure how it behaves in term of life cycle though. You will need to look it up if it s what you want.