I am developing an SMS app. I am getting messages from the Android Database every time user opens the App.
On a device with around 100 messages, it works fine. But with a device with 10,000 messages the app takes around 20 seconds to display the list after getting all the information.
To solve this, I am thinking about three possible options here:
Should I consider saving all the data to my own database? Will it make it faster?
Should I get some messages first, and then the rest in the background?
Any other option you might suggest.
Thanks in advance.
Below are the answers of your question
1. Should I consider saving all the data to my own database? Will it
make it faster?
No, don't do that. This will not make it faster. Same response you will get.
2. Should I get some messages first, and then the rest in the
background?
You can do this, but there is no need to do this to get all messages in background.Because User can see limited number of messages and chances are he will not see all messages down the bottom. So it will be useless to get those in background (untill or unless there is a business requirement)
Any other option you might suggest.
Yes, you need to implement pagination and need to keep track how many messages are needed to be loaded first time and while user scrolls then get more messages. In this case you need to keep track your own about how many messages you have already loaded and how many more you want to load. TO achive this, you will be required to implement PULL TO REFERESH mechanism of android. And a lot of tutorials can be found over the web.
Hope that answers your question.
I have a app working offline. It is assumed that 1000+ records are created with images in each record during this period and whenever connectivity is established. What should be the approach to send all the 1000+ records to server that also handles any interruption between the network calls or API failure response.
I assume I have to send records in batches but how to handle the interruption and maintain consistency and prevent any kind of data loss.
I guess the best way here is to send each record separetely (if they are not related to each other).
If you have media attachments, sending of each record will take 2 seconds in average, if you uploading via mobile internet with speed ~2 MB/s. If you will send the large batch of records via each request, you must have stable connection for a long period.
You can send each record as multipart request, where parts are record's body and media attachments.
Also you have no need to check for internet connection, or use receiver for catching changes of connection state. You can simply use this libraries for triggering sync requests:
JobScheduler
Firebase JobDispatcher
Evernote android-job
I would suggest to use Firebase database API.
It has got nice offline/online/sync implementations.
https://firebase.google.com/docs/database/
And it is possible to read/write the data using Admin SDK for your NodeJS server:
https://firebase.google.com/docs/admin/setup
You can use divide and conquer approach means divide the task into small task and upload the data to the server.
1. take a boolean flag "isFinishData" starting with false.
2. starting upload the data on server from 0 to 100 records.
3. next record send from 100 to 200.
4. this process run until last record (1000) is not send .
5. in last record update set boolean variable true and exit from loop .
this logic would be work fine in IOS/android both.
Save your records in local Db and use ORMs for it. Use Retrofit which provide onSuccess and onFailure method for Webservice calling. To send data to server at regular interval you can use sync adapter.
1st I need to know how did you save image in local db ?
You need to create a service to catch connection status. Each time when connection is established, you submit your record as Multipart kind. You can you Retrofit/Asynctask.
Just submit 1 record per one Retrofit/Asynctask, it makes you ez to handle success/fail of each record.
You can run a single or multi retrofit/asynctask to submit one or more record, it's up to you.
If ur data has image, on server side, you have to handle process from ur server to 3rd server ( server to save image ).
This is a very broad question and it relates to Architecture, UI Experience, limitations, etc.
It seems to be a synchronization pattern where the user can interact with the data locally and offline but at some point, you'd need to synchronize the local data with server-side and vice-versa.
I believe the best place to start is with a background service (Android, not sure if there's a similar approach on iOS). Essentially, regardless of whether the Android app is running or not, the service must handle all the synchronization, interruption, and failure in the background.
If it's a local db, then you'd need to manage opening and closing the database appropriately and I'd suggest using a field to mark any sync'd records so if some records did fail, you can retry them at another point.
Also, you can convert the records to json array, then do a post request.
As for uploading images, definitely needs to be in batch if there's a lot of them but also making sure to keep track of which ones are uploaded and which ones aren't.
The one problem that you will run into if you're supporting synchronization from different devices and platforms, is you'll have conflicting data being synchronized against the backend. You'll need to handle this case otherwise, it could be very messy and most likely cause a lot of weird issues.
Hope this helps on a high level :)
To take on simple approach ,have 1 flag in your data objects [NSManagedObject] classes as sync.While creating new object / modifying an existing object change sync flag to false .
Filter data objects with sync value as false.
let unsyncedFilter = NSPredicate(format: "sync = %#", #(false))
Now you will have an array of objects which you want to sync with server.If you are sending objects one by one in requests.
On success change sync flag to true else whenever your function gets executed again on app launch/reachability status update, it will filter out unsynced data again & start synch.
As others have mentioned this is a rather broad question. A lot depends on both the architecture of the server that will receive the data as well as the architecture of the app.
If you have any control over the implementation of your backend I would recommend implementing a storage solution that allows for pausing and resuming of transfers. Both Google Cloud Storage and Amazon S3 offer a similar functionality.
The idea behind this approach is to be able to pick up the upload from where it stopped. In case of app crash or issues with internet connection you don't have to restart all from the beginning.
In your case I would still start separate uploads for each one of the records and store their upload progress.
Here you can find an example of how to use the pause / resume approach using the mobile SDK with Amazon https://aws.amazon.com/blogs/mobile/pause-and-resume-amazon-s3-transfers-using-the-aws-mobile-sdk-for-android/.
Editing adding reference to Amazon iOS SDK , http://docs.aws.amazon.com/mobile/sdkforios/developerguide/s3transfermanager.html
Best way is to break the files into chunks of 100s and upload at intervals or when app is idle.
I was wondering if it is possible ( it should actually) to run a piece of code every couple of minutes even if the user is using the app. The basic Idea behind this is that the User will take the smart phone with my app loaded in the field and start collecting data, while he is collecting data or playing with other options of the app the phone catches the 3g/wifi zone it will start syncing the data to the server. I keep pushing notifications to the devices from my web service using Google Cloud messaging (GCM) and when it reaches the phone it means the phone is now connected to the internet I run that piece of code which do the sync for me. Would it stop the current activity of the app or I would say do the user will be able to keep collecting data and the sync is also running on the background?. any idea of this type of scenario?
thanks guys.
Anything that communicates with a server is by nature asynchronous in ActionScript (and you can't make it synchronous). So just do what you'd normally do to communicate with the server. Other processing, such as loops over a large collection or drawing a lot of objects, can make the application unresponsive.
Yes it is possible using AsyncTask. And your application will not stop while AsyncTask is running in background.
I am able to fetch contacts using this code https://stackoverflow.com/a/1780818/992774 , it works perfectly fine and returns all the emails and phone numbers.But my problem is that when I have 10,000 of contacts it takes about 3-4 minutes and for that time it blocks my UI and looks like my app got halted. I have seen many apps like groupme which shows contacts without taking any time.Can anyone suggest how to reduce the time while fetching contact thousand of contacts or how can I create custom cursor adapter?
Can you do the loading in a separate thread, either using a Handler or an AsyncTask, for an example please refer to this tutorial http://www.vogella.de/articles/AndroidPerformance/article.html
This will leave your UI thread to be free to do UI stuff and you should be able to see your contacts get populated one by one on your screen.
use CursorLoader to get your cursor. It runs asynchronously, so you won't hang your UI thread while you're retrieving data.
It still may take some time. Is it worth stepping back for a second and asking if you need to look at 10,000 contacts? Seems to me that it's nearly impossible to search through them on the screen.
so i was wondering if its possible to for an application that i would write to be constantly running in the background and alter regular phone operations. For example this could be something like as soon as you receive a text from anyone you forward it automatically to another number. Is something like this at all possible?
Just to be clear I don't want to solve that particular problem through some other means, just want to know if apps can accomplish that.
Also if that is possible is it possible for an app that i write to alter more immediate and instant things, like an incoming call.
thanks all for reading this, and hopefully a helpful response :)
It depends on how far you want to go, but I would expect that what you want to achieve probably isn't possible.
The Android OS does reserve some actions and prevent them from being doing programmatically. For example, you can display the Dialer with a number filled in but the user has to press the call button to make a call. Similarly, you can display the SMS app with a message already written but it is up to the user to send the message.
I don't know for sure, but I assume this is for security. For example, let's imagine you could write an application which could start a call with no user interaction. I would release my Super-Handy-Dialer application which makes quick calls for you making you life easier, but what it also would do is wait until 2am and call my premium rate phone line every night for 3 hours.