Develop Reference

FCM Cloud Messaging difference from Notifications and Message

I implemented my backend service (using java and FCM) to send push-notifications to mobile apps.
I implemented my service using Java Firebase Admin-SDK (https://firebase.google.com/docs/reference/admin/java/reference/com/google/firebase/messaging/package-summary and https://firebase.google.com/docs/cloud-messaging/send-message#java) about this and I'm able to send (and receive) push notifications on iOS and Android mobile apps.
Now I received a request from mobile-developers that they needs to customize (client-side) the received push notifications (also when the app is in background mode).
Probably here is reported a same question: What is the difference between Firebase push-notifications and FCM messages?
Reading the documentation (https://firebase.google.com/docs/cloud-messaging/concept-options#notifications_and_data_messages) I understood that It's necessary to use a Data-message instead of a Notification message.
It's not clear for me what's necessary to change to support this delivery type.
Do I change the Android-config of the FCM-message or Do I remove some unnecessary data (just set all info into the custom data without others info for example Android configuration etc..)
It's possible to have a small example?

If your json will have notification key, developers will not able to handle notifications in background. They will receive this notification only when app is in foreground. In case when developers should receive “silent pushes” or they need control all notifications, you should remove notification key, and use only data key.

This can be achieved by changing the key 'notification' to 'data' as follows:
{
"notification": { //replace this line by "data"
"title": "Hey Gajanan",
"body": "Thanks for visiting omnidecoder.com"
},
"to" : "YOUR-GENERATED-TOKEN"
}

Making API calls while app is killed/not actively running

So I am making an app that has to check for some information, but I need to be able to do that while the app is killed/not actively running. So basically like Youtube's notifications or something. I am a beginner and watched some tutorials on FCM, which can send a notification while the app is killed, which is fine. However, I need to be able to periodically make API calls, check if a certain condition is true and send the notification if so (all of that while app is not running). I tried googling that and found nothing that can help me. So... any ideas? (No code included since I don't think it's relevant.)

If this condition only affects the display of notifications, you can simply check the condition when you receive a notification through FCM. Here's an example :
class FCMService : FirebaseMessagingService()
{
override fun onMessageReceived(message: RemoteMessage)
{
val myCondition = getConditionFromAPI()
if (myCondition) {
showNotification(message)
}
}
}

Use AlarmManager to request periodic runs of your code. It may be set up to broadcast a message time to time to your receiver (declared in AndroidManifest.xml or in your code).
It will work while device is on. To continue after reboot, you have to set up a receiver for Intent.ACTION_BOOT_COMPLETED and register it in your code (not in AndroidManifest.xml, as it no longer works in latest versions of Android).

check automatically for new message android

I am trying to create a simple android messaging app. So basically let us assume that user A sends a message to user B. I would like that user B receives a notification when the message is received. I know how to create the notification and all. But basically I would like to know how the user B constantly checks if a new message has been received even when he is out of the app, and then that would trigger the notification and subsequent actions.
Thank you

You have to setup an unbound background service.
With this you can constantly make pull-requests to your server or get push-notifications from your server and display notifications.
https://developer.android.com/training/run-background-service/create-service.html

You can use Event Bus lib for this purpose. When new message will be received it will create and event and then you can receive that event event and do other operations.

If you are talking about text messages then you will have to create a BroadcastReceiver
http://developer.android.com/reference/android/content/BroadcastReceiver.html
You can see my answer here for SMS Receiver
Verify sms text message by app before it displayed to user
Don't forget to give permissions in your app's manifest.
Hope it helps.

Is it possible to send a message from one app to another?

I have a text messaging app that I want users to be able to text another app of mine on someone else's phone that will show up within the app. Printed on screen. I have one app that will send the message and one app on the receiving device that will display the message. How would I go about doing this?
The receiving app is an opengl app that will display the message in front of a 3d model from the sending app.
If someone could help me out or get me going in the right direction, I would greatly appreciate it. Thank you for your time.
EDIT: This is what I'm doing. I'm making a live wallpaper that women can put on their phone, a seperate "regular" app will allow the husband, fiance, etc to send a message to the lwp on the significant others phone that will display at the top half of the lwp screen.

public void sendSMS(String phoneNumber, String message)
{
PendingIntent sentPI = PendingIntent.getBroadcast(this, 0,
new Intent(SENT), 0);
PendingIntent deliveredPI = PendingIntent.getBroadcast(this, 0,
new Intent(DELIVERED), 0);
SmsManager sms = SmsManager.getDefault();
sms.sendTextMessage(phoneNumber, null, message, sentPI, deliveredPI);
}
You can do something like this for sending the sms.

Yes, it's possible.
Use SMSPopup as a working Android project you can use. It has the two parts you need: the sending part and the receiving part, and it's open source. Here it is on Google Play.
The only issue is that the user probably won't want those application messages intermingled with his normal SMS messages.
So you'll want to tag your application text messages with a unique keyword so that the receiving app knows it's a message for itself and no one else. And by tagging, I just mean to insert a unique keyword at the beginning of its subject line.
And your receiving app will have to register a BroadcastReceiver with a priority of 100 so that if it detects a message intended for itself, it can just delete it from the content provider and just do an AbortBroadcast so that the other text messaging apps don't beep for a message that wasn't meant for them in the first place.
In that sense, SMSPopup probably already does 90% of what you need. SMSPopup doesn't automatically delete the sms it receives, nor will it filter them on a particular keyword, but it must silently swallow them so that the normal notification system for sms doesn't get triggered (since SMSPopup provides its own notification popup interface instead).

Hi Steve we have RabbitMQServer to send messages between apps. We should configure the server and need to implement functionlities to send and receiving messages.
You may get details about RabbitMQ server at http://www.rabbitmq.com/.

How to register for SMS database changes?

How can I register for SMS database changes?
I tried:
mCursor = mActivity.getContentResolver().query(Sms.CONTENT_URI, new String[] {
Sms.ADDRESS
}, null, null, null);
mCursor.registerDataSetObserver(mydataSetObserver);
where mydataSetObserver is implemented like this:
private class MyDataSetObserver extends DataSetObserver {
public void onChanged() {
System.out.println ("1");
}
public void onInvalidated() {
System.out.println ("2");
}
}
But when I tried sending a SMS message in the emulator,
MyDataSetObserver never get called.
Can you please tell me why?
Thank you.

It sounds like all you are trying to do is have the ability to make changes to the SMS database on the device.
The way I have done it in the past is by using tags in the AndroidManifest.xml. The application I made needed to use the READ_SMS permission as well as the READ_CONTACTS permission, however gaining permission for writing to the database would be done in the same way.
I defined these desired permissions in the AndroidManifest.xml file with the following tag:
Included in the list of permissions you can use is WRITE_SMS, which should give you the desired capability.
Please note: because I am a new user, StackOverflow would only let me post one hyperlink for this post, I tried including alot more information however was unable to do so. Please go to the android developer website and search for the AndroidManifest.xml file and see more info if need be.

DataSetObservers only observe DataSetObservables they are registered with. Your MyDataSetObserver is registered with your mCursor and will be notified whenever mCursor changes (e.g. after requery) but not when the content is written by another process (like the Messaging application).
Unfortunately there is currently no good way to listen for the event of sent text messages, the best alternative seems to be polling content://sms/sent, potentially using a ContentObserver.
This question is related.