I'm trying to use GCM to establish communication between some users. They should send to each other their GPS location. Is it even possible? There is a subscribeToCloudMessage method but I don't know whether it will be useful or not.
Info: Server works fine (Google app-engine) with all the required keys.
It's possible for one app to send a message to another app via Google Cloud Messaging if the sending app knows the registration ID of the recipient app. Usually when a app register to Google Cloud Messaging, it sends it's Registration ID to a server, and that server sends GCM notifications. If you want the app to send the notifications directly, you must send each device (where the app is installed) the Registration IDs of other devices that it needs to send messages to.
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Is there any way to send push notifications to the users who have installed the app but not opened yet. I am using firebase to send push notifications.
In order for Firebase Cloud Messaging to send messages to an app on a specific device, the app must have collected a device ID token. This requires that the app have been launched at least once, so the app code can get that token and send it to your backend. If the app was never launched, that means it never had a chance to collect that token, and messaging to it is impossible.
I was wondering how android push framework is able to distinguish data recieved via GCM and forward it to the appropriate android application for which it was intended ?
Can anyone let me know how it is done ?
You question : how android push framework is able to distinguish data recieved via GCM and forward it to the appropriate android application.
From your question it looks like you willing to know about data
workflow & Client Server architecture that exists in applications
which are using the GCM service.
As per google’s documentation “Google Cloud Messaging for Android (GCM) is a service that helps developers send data from servers to their Android applications on Android devices”. GCM is a service provided by Google for developer that helps developer to send data from server to any number of Android devices.
Simplified Application Specific Work-flow:
The push notification can be broadcasted either to the mass audience
or a select set of users. Mass audience is targeted when the
notification has to be sent about a marketing campaign. A subset of
users are targeted when a personalized information has to be sent.
The below steps explains how push notification works on android devices:
First android device sends sender id, application id to GCM server
for registration.
Upon successful registration, GCM server issues registration id to android device.
After receiving registration id, device will send registration id to our server.
Our server will store registration id in the database for further use.
Whenever push notification is needed, our server sends a message to GCM server along with device registration id (which is
stored earlier in the database).
GCM server will deliver that message to respected mobile device using device registration id.
This can also be understand using following figure
An Example Workflow:
So, from above images it easy to understand that whenever the android
application is first installed by the user, then it registers itself
to GCM server, and obtains unique GCM ID, then it's our Host servers
responsibility to keep this newly registered Registration ID of the
android user into Database, and then it will be used whenever server
side application willing to send the message to that particular
android user.
So, let us consider one case; suppose an Server wants to send Some data to Android User, which has already registered it's GCM ID 1234567 when it's first time installed, and as it's in the server's database the server application will fetch it from DB, and simply make a HTTP POST request to the GCM server in JSON format, which will have registered user's GCM ID along with the data to send , in same way the GCM Server has the record of all the Registered GCM/Android Clients, it directly forwards that message to the intended android user, and android app in user's phone will raise and Notification alert, to indicate an push notification has arrived.
Hope This answers an question!
GCM stands for Google Cloud Messaging.
Every push notification receive on any Android device is sent by the GCM only.
sender -> GCM -> Android Device
when sender sends an push notification then it goes to GCM. GCM receives that push and forward it to particular Android Device by its Unique device id.
GCM can't deliver Push without Unique Device ID.
while implementing push notification there are two important things, application key and server key ... these are unique Keys.. using these keys GCM identifies the application to whom push notification is related
Can anyone help me with a way to send requests as a notification through my android app to all the users who have installed my application and then their responses are sent back to the user who sent the request.
I have read about GCM but I dont understand how can I register all the users to get their GCM registration ID and how can i simulataneously send a notification to all users..I may sound naive but I am completely new to this GCM concept and I dont think that it is the exact thing what I am looking for..
So,somebody please tell me how to send notifications(simultaneously on click of a button or something..) to all the users who have registered in my android app .
You will need to build a server component that keeps track of all registered users. This component will be an app that you write and expose in the cloud. There are many app-hosting services to choose from. Amazon EC2 is one example.
So the app flow would be something like this:
User launches your Android app.
Android app registers itself with GMC. GCM will respond with a token that represents that device.
Android app POSTs that device token to your cloud application.
Cloud application saves that token. The app should now have a list of tokens that represents all active devices running your app. (of course you may want to have an expiration policy - i.e. remove all tokens corresponding to devices you have not heard from in say 30 days).
One of your app users posts a message that s/he wants to broadcast.
Your Android app responds by sending a request to your cloud application.
Your cloud application responds to this request, by making a request to GCM. In this request (or series of requests), the app will include all device tokens and the user-entered message.
GCM responds by pushing the message to all devices with your app (i.e. all of those that have register with GCM and received a token - see step 2).
If using GCM alone you would need to write a server component. I get the impression you don't want to do this. You could use Urban Airship push messaging, which will allow you to send out a message to all registered apps from the Urban Airship web portal. Urban Airship integrates with GCM (which is easy to setup). You would still need to add code to your app to handle the push notification the app receives.
http://docs.urbanairship.com/build/android.html
can someone explain about how push notification or message in android working? Does it operate within a VPN? How can the server send data to the device if it's not in the same network? Is it possible to make your own push notification/message? Please enlightened me :)
Push Notification in Android means, Google Cloud Messaging. First we need to enable google cloud messaging service from google developer console. Then need to create browser key to give from server side.
Now, when user need push, we have to register the device id to the google cloud server and it saved it permanently.
Now when server fires push at that time server request google cloud to send message to registered device id, and using that device id, google sends message to that particular device. So basically, whole things are depends on Device id.
I read about Google Cloud Messaging at http://developer.android.com/google/gcm/gcm.html.
It supports Third Party Application server to Android application push notification.
I am wondering whether it is possible to implement the same thing push/receive notification from an Android app on one mobile to the same Android app on another mobile using Google Cloud Messaging.
If not, is there any other free service available similar to Google Cloud Messaging?
An Android device can send a GCM message to another Android device. All it needs is the API Key (of the Google API Project ID that the app uses to register to GCM) an the Registration ID of the other device. Using these parameters it can send a GCM message to another device via an HTTP request.
Usually applications that use GCM require a 3rd party server in order to store the Registration IDs of all registered devices. If your app has a different way to let devices share their Registration IDs with each other without requiring a server, you don't need the server.
As far as I'm aware, there has to be a server in the middle to send the push notifications (Android -> Personal Server -> GCM Server -> Android)
So the Android device sending the notification would send some data to a script on the server (using a HTTP GET/POST), and that script would then send the push notifications to all the devices that you wanted it to
Following the example Code from google (GCM Client Example), you can build an app to get a registration ID for your device, but sending messages without a server wouldn't work in my opinion. I didn't tried by now, but what about using the Google Backend Starter, or (what I tried) using a Backend as a Service Provider like apiOmat if you can't afford or don't want to set up a server.