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
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I am doing a lot of long lasting computation stuff in java and want to stay informed.
Is there any standard method ( library etc. ) to send push notifications from a desktop java program to my Android device?
When there is no , could someone provide me with some starting ideas how to write this on my own?
The "3rd-party application server" mentioned in https://developer.android.com/google/gcm/server.html can also be a desktop pc running a simple java program.
You will need to setup some IDs, an app that receives push messages, a way to display the phone registration ID so you can enter it in the desktop app.
But the rest is basically as simple as adding the gcm server jar to a desktop app (I'd use this version here: https://github.com/kurthuwig/gcm/commit/d37f4d1c37ed8deaf1a161ca7b881c1d843f80df ) and then calling 3 methods or so.
Like what zapl suggested I would say GCM is a good choice. Also, all benefits aside, if you're into messaging you can have a go at AMQP, specially the RabbitMQ implementation. You can run the RabbitMQ server on your desktop and push your messages out to all listening devices.
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.
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.
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
I've been working on an android application and I am trying to figure out how to implement a messaging feature for the application to send messages to other phones and to my web app. I have been doing a fair amount of research and I haven't yet found any ways of going about this, or at least not any straightforward ones. Could someone point me in the right direction with this? Is there a relatively simple way to get this functionality? I have found links that show how to use google's cloud service but I am extremely unfamiliar with this so I was wondering if there were other better/simpler implementations or instructions out there. Thanks in advance for the help.
For security and privacy reasons, your phone/tablet app cannot (should not) communicate directly with other devices (unless they're on the same WiFi or similar and explicitly bound via bluetooth .etc)
So the way to do this on Android is use Cloud to Device Messaging (C2DM).
Your app will send a web request to your server, with the message and intended recipients.
Your server will look at this, find the C2DM IDs of the recipients, and send the message to Google's C2DM service, which will then be pushed down to each device.
Your app should have a C2DM receiver to receive these messages and process them.
Check here for more information on implementing C2DM
http://code.google.com/android/c2dm/