When I program apps, usually I need to do something that can fail (the most typical is send something to a server), many times the "send and forget" would be the best option (or a send and forget with a expiration date).
I know it is a very generic problem but is there some library that facilitates the save and retry process?
As #CodeChimp says, you'll probably need to roll your own.
That said, the usual pattern for Android is to write a Service that handles saving/retry.
Your app would pass the data to the service (send and forget), and the service would then take care of trying to send in the background.
The big question for this sort of thing is always how to handle failure. What happens after the save fails some number of times? You're on your own here too. Depending on your situation, you could notify the user (via a Notification), save the error in the app's database, and notify the user in the app's UI, etc...
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I am going to develop uber-like application.Here I have to send latitude and longitude to web and mobile devices continuously with my service,What I have do to get this.
Can anyone please give some idea.
You should start by designing how the application is to be used, seen from all the different users perspectives.
For instance is this a web app, or a native app, or both?
Then from that knowledge, you need to define a communication protocol.
You should be able to determine if the client will be polling for data, or if you need to push it from the server onto the clients.
This also goes for the data that travels the other way.
From here you choose a language for programming, and then start doing some proof of concept tests.
The choice will depend on the chosen underlying technologies
(web / native / os / available libraries)
After some test work you may have something that works, then you need to review or add security to the communication, cause we do not want everyone collecting location data from everyone that has the app installed.
Then run beta trials and eliminate the worst bugs, and then release the app.
You'll want some sort of asynchronous task which can get new data from your server and refresh the mobile and web content to reflect the content of the server. You'll also want to notify the server whenever you make local changes to content and want to reflect those changes. Android provides the SyncAdapter pattern as a way to easily solve this pattern. You'll need to register user accounts, and then Android will perform lots of magic for you, and allow you to automatically sync. Here's a good tutorial: http://www.c99.org/2010/01/23/writing-an-android-sync-provider-part-1/
I am implementing a small social networking website, and I am trying to implement notifications.
Notifications have the following requirements
All users will receive notifications whenever users they follow do
certain events (like a post, create a post,leave a comment, etc...
When a set of notifications for a user is unread, just like on facebook, the user will
continue to see a read notification icon on their navbar.
Problem : I am taking an example to describe my problem for better understanding for everyone.
Suppose there are two users A and B. A & B are friends and A post something, suddenly B like the post of A then A should have to receive the notification immediately.
So how can i achieve this immediately receiving of notification process?
Should i send a call to server on each millisecond to check whether there is any unread notification is available for A user ? In this case thousand millions of call creating for multiple user. It is feasible solution ?
(I think it create unnecessary load on my website. As i think facebook and stackoverflow do not use this way).
Provide me a suitable solution just like fb and other webiste using.
Technology Using in my project: Java and MYSQL
You should use JavaScript (client side) along with Java - MySql (Server side), and more specifically Ajax. You will need some time to understand the concept and the usage but it does exactly what you want.
To give more details, what you need is to create a partial view where the notifications will appear, and update this partial view async (with AJAX).
Dont reinvent the wheel.
Use ajax call to server at each interval and check your server and update nav acc.
1.So how can i achieve this immediately receiving of notification process?
2) Should i send a call to server on each millisecond to check whether there is any unread notification is available for A user ?
Your above both questions answers solve through GWTEventService implementation.
Through it you can write code that will avoid client to server round trip.
GWTEventService is an event-based client-server communication framework. It uses GWT-RPC and the Comet / server-push technique. The client side offers a high-level API with opportunities to register listeners to the server like to a GUI component. Events can be added to a context/domain on the server side and the listeners on the client side get informed about the incoming events. The server side is completely independent of the client implementation and is highly configurable. Domains can be defined to decide which events are important for the different contexts.
Refer link: https://code.google.com/p/gwteventservice/
I have read different posts about forcing an update of an app, and the only idea that ppl has had (as far as I can tell) is to create a web service which the app calls to see what version is the current one. The WS must them manually be updated to reflect the versionCode.
This approach has several problems:
Problem 1:
When you upload an app to the Play Store, then it takes several hours before it is available for devices to download, and you never know when. Also, it seems to me like it becomes available at different times for different devices, so you really have no clue what so ever when its "available for all".
This means that you cannot immediately update the WS (that tells the app what is the "current" version) since directing them to Play Store won't be very constructive, as the updated app isn't available there anyways. And since you don't know when it will be available, you don't really know when to update the WS.
Problem 2:
Sometimes you do some changes to the back-end (comm protocol changes or something else) that requires you to upload the new version of the app and then update the backend so that they can talk to each other as expected. In this case, you really want some way to tell the app that "please update since you are out of date" and direct them to the Play Store.
So, the question is, how can I achieve this functionality?
As zapl has commented, the backend should ALWAYS allow backward compatibility. Whenever your app makes a call to the backend server the app should report its version number and the backend should respond accordingly.
As for forcing an app update, you should look at GCM to push a notification which will then take the user to the update although in reality this wouldn't actually 'force' the user to update.
Either way, as long as both the backend and app report their version numbers to each other (perhaps with a notification of 'update available') then you can design things so 1). they continue to work and 2). users will update ASAP when they need to.
I understand that publishing to Google Play can have delays but as long as the backend retains backward compatibility, it shouldn't be a problem.
You can use appgrades.io to force app updates using custom view/popup that you can design (no code required) on appgrades Dashboard
I'm (sort of) new to android development and I'd like to create an android messenger app based on the PircBot library.
There're several constraints I am aware of right now:
must use IRC, probably can't change this now since it's already in the requirement
IRC service needs to run in its own process so it doesn't interfere with UI while listening to IRC messages and it should receive messages in the background and send notification without having UI showing
I'm using different activities for different screens so all activities will need to use the service (logged in, joined channel, send/recieve message) and different activities should be notified based on the current state of the connection.
I've tried to bind the service from my activity but binder seems to only work with services in the same process. (I'm not sure on this one, search didn't return anything useful)
What's the preferred way to structure my project so that all the constraints can be satisfied? Also what other problems might I ran into?
Sorry for the bad english
IRC service needs to run in its own process so it doesn't interfere with UI while listening to IRC
I don't see any reason why the IRC service would need to run in its own process. A service, is, by definition, an element that does not interact with the user, as stated in the docs:
A Service is an application component representing either an
application's desire to perform a longer-running operation while not
interacting with the user or to supply functionality for other
applications to use.
And, as you said, by making this service run in its own process, it becomes impossible to bind to it (indeed, you need to do IPC communication at that point).
I'm using different activities for different screens so all activities
will need to use the service (logged in, joined channel, send/recieve
message) and different activities should be notified based on the
current state of the connection.
To satisfy this requirement, you can simply use the LocalBroadcastManager to share information from the service to all the activities. Your activities could have BroadcastReceivers for the events they wish to hear (connectionStateChange, MessageReceived, etc.), and would act accordingly.
Finally, because reading other people's code is always a good idea, check out these two similar projects, brought to you by your friendly search engine:
Android's SMS/MMS app
A simple IM app for Android
I want to make my app run in the background like a process that runs always.
I need it because I want to get locations update for GPS every 2 minutes (longitude, latitude) and to use the information in a method.
For that I need for the app to be running when the phone is asleep or not in the UI of the app in other words I need the app will run always.
I'm sure that there is a way to make it , thanks anyway for any answers :)
This was just the first google search result I found:
http://www.vogella.com/articles/AndroidServices/article.html
The answer here is to use a service, if this tutorial is lacking there are 6.4 billion others.
We have something like this, but it is made up of several parts.
Firstly you will want your code to run (and be registered in the manifest) as a Service
You will probably also want to request android.permission.RECEIVE_BOOT_COMPLETED so that you can write and register a BroadcastReceiver that gets notified by android.intent.action.BOOT_COMPLETED action and its onReceive method kicks off the service.
In our case we also have a front-end activity which also pokes the service to make sure it is running, but it's been a while snce I checked to see if this was still required.
Our service is nearly empty and onCreate immediately calls a custom Handler which then manages the 'ticks' which wakes the Handler and fires a Runnable if there is work to do, but this is where my code diverges from yours. In our case we only attempt to update the GPS location when the service 'ticks' (usually every minute) and there is work to do. It usually only performs a couple of dozen operations per client per day so I can't really advise on how it will impact battery usage.