I want to gather data in online/offline mode, and when the internet connection is dropped data should be store in locally, and once the internet connection is back data should sync/push to the server.
What library or technique recommended for achieve that?
Try to store data in offline using Room data base or Sqlite. after storing the data check internet connection continuously, if internet has connected upload that data to your server and drop local data.
Related
I am developing an app that uses a database to store the data on the server, but I am trying to save some of the data locally, and in the event of no internet connection being established, save new data locally to the device and synchronize any changes to the server when an connection is re-established. What is the best and most efficient way to do this?
I have been looking at Androids Room persistence library and it seems like the logical choice, but I am not sure how it goes about synchronizing changes to/from the local storage database. I have looked at multiple threads and forums for help, but have had no luck so far. Please help.
One way is to build your own sync adapter: https://developer.android.com/training/sync-adapters
You will need to handle most of the sync logic between the client and the server, but that allows you to use any database technology in the server. From the docs:
A sync adapter doesn't automate any data transfer tasks. If you want to download data from a server and store it in a content provider, you have to provide the code that requests the data, downloads it, and inserts it in the provider. Similarly, if you want to send data to a server, you have to read it from a file, database, or provider, and send the necessary upload request. You also have to handle network errors that occur while your data transfer is running.
A sync adapter doesn't automatically handle conflicts between data on the server and data on the device. Also, it doesn't automatically detect if the data on the server is newer than the data on the device, or vice versa. Instead, you have to provide your own algorithms for handling this situation.
Use firestore and enable offline data persistence. https://firebase.google.com/docs/firestore/manage-data/enable-offline
I'm working on an shopping list app where all the family can connect to the same list.
How can i make and save the list on one device and then connect from all the devices to the list?
What you need is the concept of Websockets.
WebSockets represent a long awaited evolution in client/server web technology. They allow a long-held single TCP socket connection to be established between the client and server which allows for bi-directional, full duplex, messages to be instantly distributed with little overhead resulting in a very low latency connection.
Thats means if you create a server with a web socket connection, and you allow other clients(android) to connect to that connection. You can send messages back and forth and every device connected will recieve it. All connected is how i like to call it. Think socket.io and node.js.
You can't fetch the device data without having a medium or network in between them and if you choose Bluetooth or wifi then your data will be local and other family member living another city won't be able to contribute. so at last if i'm guessing right you need a synchronised database which can give you realtime updates from another user.
This is where Firebase Realtime database comes in. you can use it in your project, it's easy and takes few minutes to configure.
since all the user will have their own app they can contribute to same database and others can see it instantly.
Read the docs here for android
I am just a beginner in android app development and that's why I have many doubts. I am building one application where the user enters some data in editText. Now I want to save that data in my database. My database is running on my laptop. How would my app connect to the database? Do I need a web server in between? If yes then which web server is used for Android apps? Basically, i want to know the flow of data from app to the database.
Study more from Udacity.com, its free.
You may use a jdbc Connector to connect to database.
Connect your jdbc connector over local network ip\servername and database connection string
You can use REST Service when it comes to web Service on Android like this. You can either pass the values as parameters or an Object depending on your requirement. All the best
Wamp server is best option to play with server related utilities.You can use it even if you are offline. and it provides various option for data storage. It Mainly uses MySql and PHP scripts for fast performance.
For More details Click Here
I have a SQLite database which will store all the data entry on an Android application. It will then check if it has a Network Connection - If it does it will send a JSON post to a Restful web service.
I was going to do it straight to the web service and then save it in the SQLite database if there was no connection , but what if connection is lost half way through the transfer?
What should I do if I lose Network Connection? My suggestion on this would be the following
Insert data into SQLite Database to store data
Check the connection every 5mins. (What if the user gets a connection in between, and then inserts the data?)
If they have a connection - get the SQLite database results, check them against the MySQL database, and insert any fields that do not exists? (Maybe put a flag in the database to see if it has been posted)
Is this a good way of doing it? Or am I thinking about this the wrong way?
Thanks
James
Consider the use of some sort of queue in your Android application which will hold requests against your web service until they are completed successfully.
http://en.wikipedia.org/wiki/Queue_(abstract_data_type)
Theme : Newspaper updates in android application.
How to fetch or retrieve data from server and post updates on android application . How to manage offline storage means whenever there is no internet connection how the data gone be updated on android application , atleast how it consider showing updates on android application . If any one known this issue please answer about it .
I am actually using php or json as intermediate files for fetching data from server and send updates to android application but its seems to be more complex and if i wont get the permission to access the server side files , how do i manage for updates ? whether is it necessary to have permission to access the server files ?
More about the topics : if i want to syncronise the update with website , how do i handle it or implement it ? i am not asking any sort of coding here .
How to fetch or retrieve data from server and post updates on android application
use HTTPClient.
How to manage offline storage means whenever there is no internet connection how the data gone be updated on android application
I think you don't understand what offline storage means. If there is no internet connection, that's it. You are not able to update your content. Offline storage is useful if you have internet connection, but not everytime. The content you downloaded when you had internet connection can be saved to SQLLite to be loaded when you don't have internet connection.
I am actually using php or json as intermediate files for fetching data from server and send updates to android application but its seems to be more complex and if i wont get the permission to access the server side files , how do i manage for updates ? whether is it necessary to have permission to access the server files ?
Create WebService as an interface. Do not let other system to be able to directly access your files. Or just create a PHP files that basically return Json or XML Data.
Other option : create an RSS.
More about the topics : if i want to syncronise the update with website , how do i handle it or implement it ? i am not asking any sort of coding here .
Create an event to start sync using HTTPClient. If there is new update, save it to SQLLite(for offline storage) and display the content. The event can be triggered during the start of your application or clicking refresh button and if Internet exist.
Update :
There is a new framework called couchbase mobile. You can sync the local mobile db from a couch server. You can insert/update the data locally(offline mode) and then the data can be synced also to the couch server, whenever you have internet connection. This means the need to create HTTPClient is no longer necessary.
For the database, try cloudant.