Quick and probably stupid question here,
I am pulling JSON data from my server and displaying it in my app in edit texts
I am using volley to GET the data, the JSON data are Dates in the fomat of MM/dd/YYYY so lets say its for ex. 03/12/2020,
but now My problem is my App displays it as 3/12/2020 and postman does the same, so the 0 goes missing but i am pulling the data directly from my SQL , which includes the 0,
I have learned that Json Removes leading 0's for various reasons,
But how can I add the 0 back to the json within android java using volley
Will Post Code if needed
AFAIK date, formatted like this, should easily be parsed so that you get object of class Date or something similar. After you have this, you can format it any way you want (depends on the object being used, though).
Related
I'm writing some Android app which pulls data in JSON format and I'm using retrofit library.
I've got one question, do I need to make POJO class which contains all fields that JSON object has? because in my case JSON objects from API have about 40 fields and I need only few of them.
I have done some test with sample app. There were JSONs containing 3 fields and when commented everything related to one single field app stopped loading and showing any results (no adapter attached error).
So I'm guessing that I have to make call for full JSON object and eventually not inflate all data into views?
Implementing and managing remote or cloud databases in Android Applications is new to me. I am currently making an app that would take in thousands of "entries" to a form, think of it as an attendance app. Right now I've decided to use JSON as my database type and Parse as my BaaS. I need some tips on my decision.
I don't actually see JSON suitable for this because it is a "text" file that can easily be modified or if I somehow accidentally append an extra bracket it would render the whole database corrupt whereas SQL use queries like INSERT which I think is more secure. I just picked JSON because it works well with Parse. Do you think this is a good idea?
Another is what if the JSON file will accumulate tens of thousands of entries, how do you manage this huge database? Do you split it into several files (eg. every 1k entries make another JSON file) or is it enough to just dump all the data in that one JSON database file?
When using BaaS do you just sync the data in that server or do you also make backups of some sort (I don't really know how to put this)?
Thanks in advance!
JSON is not a database, but a data interchange format. You can have a database that uses JSON for communication, for internal representation, etc. but that does not make JSON a database in itself.
Parse itself manages the organization of the data. You communicate using JSON but don't have to care about how it's stored, updated, etc. internally.
So in your app, you should use SQLite for storing such amounts of information, or, depending on the app, just send it to the Parse server and execute the queries against it. You can see how it's done in the Parse Android documentation.
In my android app I load some data (JSON) from wed server. And I need to store that data.
All data, which I want to save - it is fixed number (for ex. 5) of JSONObjects with 30-50 fields.
Is this good idea to save each JSONObject in Preference? Or will be better to use SQLite?
note: why I ask?
save in Preference - implementation take 10 minutes.
use SQLite - implementation take one or two days, and required to
edit database, when I will add new fields.
I'd prefer database, and if you need 2 whole days for a reasonably simple database setup, you should perhaps take any chance to practice with it.
However, if you're sure you're never going to have any advantage of (complexer) queries, then saving it into a database might not give you any real advantages.
I would prefer sharedpreference here , because size of data is not too big. If size of data was too big and had many fields then database would be first choice. You can save the whole json String into preference and use it after parsing at run time.
My implementation choice would be a database table that stores the object as something you can then transform into a native intermediate object. By keeping the local data stored as JSON you're potentially locking yourself into keeping a JSON parser within the app for the foreseeable future even if your web service changes its format.
For example, if your web service changes to XML you're still going to have to keep the JSON parser in the app to handle those users who upgrade the app and have to do a data migration.
You could save JSON directly in SQLite database. If you parse data and then save in database then it would take some time for you to make everything work. But think about saving JSON directly in database. It will require two fields only in database link and json response.
Advantages:
- Big time saving
- You could save the same solution in your future apps for saving JSON in database.
Disadvantages
- You will not be able to query data
- You will have to parse every-time
I am currently working on TFL based projects. And i want to parse the json file which is available in this link : http://countdown.api.tfl.gov.uk/interfaces/ura/instant_V1
So please help me out
This API is not standard JSON as written in the TFL API documentation. It us actually best parsed as CSV but watch out because I have found out that some responses are inconsistent where the first line might have 6 strings while the second might have 5 with the missing field not identified as an empty string but simply omitted. This way parsing with a CSV parser will lead to errors since you might never know what is omitted.
I have also searched for the solution and the best I could find was another API that gives standard JSON but only returns bus stop countdown via a stopCode request.
Use This Link To Access It.
http://countdown.tfl.gov.uk/stopBoard/75288
Im suprised as to why TFL uses this api for their own apps but not implement the public api to return good JSon like this one.
This API is not standard JSON as written in the TFL API documentation.so after get the content you may change that format. Use this link http://jsonlint.com/ it will validate your json format. so you can easily understand json format error
After get the content do this
JSONArray jArray = new JSONArray("["+ result.replaceAll("]", "],").toString() + "]")
now you get proper json array skip jArray 0th position this is - URA Version array.
It is not a single full JSON object, as per the TFL documentation. You treat each line as a separate JSON object. This way if/when you move to the streaming mode, you can continue to receive objects and interpreting them as they get streamed to you. Also you use the first element in the JSON array to determine how to process that particular line, or in some cases if you need to refresh the base data.
To get Data for my application, I parse a Json file, with Jackson, to (lists of) custom Objects. When I start my app, I check if there is a new Json file available and ask the user if they want to download it, else I use the "old" Json file. But every time I start my app I parse the Json. Then I use the Application Class to save my list of objects an go to my data when I want, most of the time I only need one object.
From the huge list, with multiple layer nested object, I create a simple "flat" arraylist of custom objects in which I put only the data I need to create listviews (name, id, second text and url of picture). When something is clicked, i use the id to get all the data.
Parsing this whole Json file every time is pretty time consuming and makes the startup time of my application long. Ofcourse, this sucks.
And having this huge list of custom objects saved in Application Class fills a lot of memory of my device, and sometimes after some use the class gets killed, and I need to reparse again.
Is there a way I don't need to reparse all my data?
I hoped for a process like this:
new Json file
first time parse total JSON to list of multilayered custom objects
create simple list for listviews
delete/clear the big list
some clever way to get only one of the giant items, without keeping the whole list in my memory. (maybe something with Jackson).
on destroying of the application maybe save the simple list, i read something about parceable or serializable?
Anyone knows how to achieve this?
Or has an other awesome idea?
Jackson has a streaming api. Also you can parse the json in a AsyncTask (in the background) and update your user interface once the new data is ready
I'd probably store the data in a SQLite database, in line with how the Android platform was designed.
As an alternative to streaming Jackson API (which is very fast, but still has to scan through most of the content), perhaps you could just save things in different files, one per entry? Or, if there is a way to group things, in multiple files each having some subset?
Of course, if you really have tons of entries, use of SQLite as Bruce suggested makes lots of sense.