I don't know what this is called, but it is something like syncing android application and a Web server. Examples are RSS Feeds and Weather Forecast
Does anyone know the concept behind developing application? I mean how do you sync the Android phone with a web server. Is there any programming needed in the server side and the client side(Android)
Are there any programming books that tackles this subject? Thanks.
What should I do to connect to Server from eclipse - Android?
check the whole conversation here
The server should make the data available in a meaningfull parsable format (for machines). For example RSS/XML feeds, etc. Your application should poll frequently and updates the status/screen.
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I have an assignment, but I can't seem to get my head around it. I've been tasked to create a mobile app on Android Studio using the microphone sensor to record audio (Parameters: Duration & frequency). The data/sample is then stored locally, perhaps using SQLite to store the id, date, time, location and sample. Let's say after 10 samples (this is where it starts to get confusing for me), the samples are bundled up and sent to the communication server which I believe OkHttp client is used in this case. The data gets sent to a local server (Apache?) and a website (Springboot) is used to retrieve the information and show the samples on Google Maps.
https://imgur.com/a/3cXzCQl
Link to application architecture is above. I have no doubt it is wrong, but would love some insight on it please. Also, I very new to all of this so I'm sure there are a lot of gaps in my message above. If you have any questions please feel free to ask!
Technologies I've been recommended to use:
Local Server: Apache
Website: SpringBoot
Communication tool: OkHttp
Android application: Android Studio
I am creating an app using React-Native for the front-end, Java for the back-end and PostgreSQL for the database.
One feature of this app is to allow users to add each other as friends and instant message them - just like other social networks. At the moment, security is not a priority but I don't want to create something that I will have to completely redo when I do have to make it secure!
The goal here is to give each user the ability to send/receive messages to/from their friends. They also need to be able to view the message history with each contact.
I just need some advice on the following points to get me going as I haven't gotten very far on my own:
How should I send messages from the front-end, to the Java server and then to the receiver? This will involve the app having to listen for new messages so would the Socket.IO library be the way to go for this?
How I should store the messages in the database? E.g. have a table for messages with user_ids to be used for retrieval?
I should point out that I am very new to React-Native, databases and networking so I am finding this very challenging!
I will massively appreciate any help and any examples would be fantastic!
You should use WebSocket on the server. Spring supports it
Here's a tutorial I wrote about sending messages from PostgreSQL to the browser using WebSocket, which isn't exactly what you're going to do, but can hopefully get you started:
http://blog.databasepatterns.com/2014/04/postgresql-nofify-websocket-spring-mvc.html
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
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.
A friend and I are currently working on a turn-based game with chat with both desktop browser and Android clients, with Google App Engine as the server.
We're using the Java API for GAE and using HTTP for communication with the server. We've implemented simple chat functionality, and we're getting undesirable latencies 1-3 seconds from both the browser and Android clients while just posting simple one-word chat messages.
My friend thought it would be best to use XMPP instead of HTTP, but we want to use a Google Accounts cookie for authentication from the Android client, and according to the GAE documentation, XMPP clients cannot use a Google Accounts cookie and must use the user's password.
Does anyone have any suggestions as to where the latency might be coming from, how to troubleshoot it, and/or what to do about it?
Also, is anyone aware of any opensource implementations of chat (or something similar) on GAE done in Java? Can't seem to find any.
One way to analyze the situation would be to use Wireshark to look at the network traffic during the delays.
You don't say how your chat messages are getting from one JVM to the other. If you're using the datastore, maybe try memcache?
Also, startup time is often an issue; app engine starts and stops JVMs all the time, particularly for a low-traffic app. A way to diagnose this is to reload the page a bunch of times (send more messages) and see if it gets faster after a while. It should be pretty easy to tell the difference in the admin console logs.