How can I send a notification? - java

I am developing an Android App that communicates with a server.
How can I send a notification from my server to my Android App without the use of C2DM?
Are Sockets a good solution? What are other alternatives?

I'd suggest you to develop a webservice preferably with JSON which is easy to handle. This server client architecture will hellp you to send and receive any kind of data (ranges from raw text to images or even video)
Check out C# webservices. That are very easy to start than the PHP services IMHO.

Depends on what you want to do.
have you thought on how does the server identifies the client to send the message ? In this case the android phone ?
With http you would need the client to "request" this notification.
The closest thing to an actual notification would be to have a socket connection, which the client would connect to the server. But then would require an existent connection between the two. If this is ok for what you are doing, then go ahead if you really want to avoid C2DM.
But, using C2DM allows your server to send notification to devices without a need for a request or direct connection from the client. The only thing you need to do is pass the identification of the device to your third-party server given when you authenticate with google's C2DM. After that, you just push notification data to C2DM and google delivers the notification for you.

I've used MQTT for providing push notifications on Android and it's proved to be a good, reliable, low power solution.
Some links to support my case / get you started:
http://mqtt.org/
Power Profiling: MQTT on Android
Basic Steps for Using MQTT in android

Related

How to implement push notifications on my android device

I have a very basic design of my entire application, where several users with my app on there android devices commits data to the server (I have used REST web services(java) + postgresql as my server) through HTTP post request from the android application. I am successful in achieving this and app runs absolutely fine. Now i want to implement a scenario where any change(CRUD operations) on my db on server should create a notification on my users android device. How should i achieve this with my server design unchanged? I have looked into Google Cloud Messaging, but could figure out the server implementation.
For now i have implemented db triggers on postgresql and able to get control back into java code using Notify/Listen feature of postgresql. From here i need to connect to android device. How can this be achieved. Is Google Cloud Messaging the only way? I have not seen any insert/update statements in there server implementation. Could anyone please guide me on this?
either you can use GCM or implement a Socket at server end and open a socket connection from mobile but this approach may add some additional processing overhead because it will create a daemon thread to listen socket port from mobile device.
You should use native library (NotificationManager etc.), here you can find a great tutorial.
My Advice is for you to use GCM. GCM normally takes a maximum of 4kb, so you could have your own defined "commands". You could use them to determine the requests on both ends, ie on android app and the server end. A php script on the server would help you in this.
I am working on an app where by the android app sends messages to the server via POST and the server forwards the message to the appropriate user via GCM. In my case I have very many things to share so in that case I am using commands, for example if it is a new incoming message I send a GCM to the app with one variable as the command and the rest as the data. On the android app I use the command variable to determine what to do with the data.
Kindly avoid that socket advice, it will have your app drain the battery to sustain the open socket , besides you don't have to re-invent the wheel while Google servers already has it

Send data to android app from web client

I'm trying to make it such that a click on my web client from a computer can "trigger" the android app to run its set function.
I've searched extensively but it seems like all methods need the mobile device to initiate a connection before the web server can even do anything.
Is there a way for the web client to be the one initiating? Also, is there any way to do this without notifying the user of the device, i.e. in the background? I'm using cakephp for the web client but any kind of answer will be appreciated. Thanks!
Use push notification system to trigger any action on your device. Push notification system such as Parse, PushApps, pubnup etc are available for free and some are paid too. Try them. Send a push notification and listen to that push message and on receiving trigger your action.
Use Google Cloud Messaging .
"Google Cloud Messaging for Android (GCM) is a service that allows you to send data from your server to your users' Android-powered device, and also to receive messages from devices on the same connection. The GCM service handles all aspects of queueing of messages and delivery to the target Android application running on the target device. GCM is completely free no matter how big your messaging needs are, and there are no quotas."[Google]
Here you'll find how to implement the GCM with PHP.

Push notification in local web without internet

I'm aware of GCM services for push notifications, but I have this issue.
I have a android app which will send a data to a local web server (php) that will response to another android device with the data sent, a normal push notification with GCM, I think.
But I need this to work even without internet, because it is a local web app that will work only that.
Is that even possible? Android device X send json data to web server that will send the data to other android device Y.
How can I verify that exists new data in the device Y ?
Thanks. I know its a little wierd.
Yes, it is possible. But it is not easy to develop. This is why:
Push notifications work attached to an account service. So you would have to implement an Authenticator service and then the whole push platform yourself.
I would not use GCM for what you are doing though. If it is working on a local network, you can use "polling" (request the server every now and then for updates)

What is the established way to request data from an android device

I currently have an small application that I have been using to learn java/android programming. Right now I have a setup were the app on one phone sends a request (via sms) to another phone running the same app. The remote phone receives the request and sends back some info. Next I would like to try this from the web. Is there an established "best" way to to this?
I was thinking I would have a web server send requests to the device via google cloud messaging and then have the device return the data directly to the web server. (Not that I really know how to do any of that just yet).
I see that there is a google cloud messaging return path (send messages from the device to the google cloud server, but it seems very new, do I need something like that? The main thing I want is to be able to ask the phone to do something when I want, not have it poll to see if there is a request, or just periodically update some status.
UPDATE:
Thanks to the answers below for confirming to me that I was on the right track.
I now have some basic functionality.
I started out using this gcm android demo code
https://code.google.com/p/gcm/source/browse/#git%2Fgcm-client%2Fsrc%2Fcom%2Fgoogle%2Fandroid%2Fgcm%2Fdemo%2Fapp%253Fstate%253Dclosed
and this ruby gem
https://github.com/spacialdb/gcm/blob/master/README.md
between the above two I was able to send a message to my phone pretty easily.
To get the round trip working, I setup a very simple rails app on heroku.
I included a modified version of the sample code in the gcm gem in a controller and then used
HttpPatch (needed for rails 4) to send a post/patch from my phone to my web app, the controller then echoes the message back to my phone.
I guess it would be nice to get the two way gcm stuff to work, but I am not sure there are any gems that handle that, and I am not qualified to handle a task like that :)
I would say it's the right call: Google Cloud Messaging for Android
From the site Android Developer:
This could be a lightweight message telling your app there is new data
to be fetched from the server (for instance, a movie uploaded by a
friend), or it could be a message containing up to 4kb of payload data
(so apps like instant messaging can consume the message directly).
In this case you don't want to fetch data from the server but you want to send them.
You can send them in different ways. I would suggest, since you are learning, to try a RESTful solution using one of the implementation of JAX-RS.
As a short and direct answer for beginner : GCM (Google Cloud Messaging) would solve your issue. However, if your app turned out to be something bigger, other more technical and complicated solutions are present too.
see this link.

How to implement XMPP to send push notifications

I would like to use XMPP so that my application will send out updates to an android phone (1.5 and higher). I pretty much want to use XMPP to send push notifications to the phone.
How would i go about achieving this. At the moment my web application is running on apache tomact with a number of servlets so the android phone can access information, but I'm finding it difficult understanding how I could implement XMPP so that I can push information from the server to the client (android phone).
I have tested the below tutorial
Example of XMPP with Google ID login
It uses Google ID logins. But i need to use my webapplication to do what google implements.
Any ideas?
That would depend on the nature of your push (is it a point to point or pub sub). In either case, you will need an XMPP server that your clients and application are connected to. This will be the means for your application to send notifications to the clients.
Not sure what you mean by "I need to use my webapplication to what google implements". Your webapplication would be a client to the xmpp server, just like your phones. You cannot use xmpp to simply talk to your webapplication, unless it happens to be a bosh enabled xmpp server itself, which I would guess is not likely.
You can use Smack for your client communications, and any one of the many available servers.
If the communication is directed at specific clients, then creating a chat between the application and client is probably the simplest means. If it is more of a broadcast, then you could use either MUC (multi user chat) or pubsub.
Generally, you would implement this as a pub-sub feature. Pub-sub is basically the publish/ subscribe paradigm: you publish something and they receive it.
Assuming you have an XMPP server setup that supports the pub-sub protocol extension (like eJabber), in your app, you would login to that server and subscribe to a node (where your update notifications would be sent), and with your subscription you would have to add a handler to handle any notification on that node.
On the server side, when you have something that all of your clients need to know about, you would publish the update to the same node that the clients subscribe to.
For more info, see http://xmpp.org/extensions/xep-0060.html

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