I would like some advice. I'm going to be using an sqlite database that will be pulling down information from my server and then saving it in the DB then displaying it. Could someone advise me of the best way to populate the DB, should I...
Use a http request and return a string de-liminated with say a | and use a loop to write to the data base.
Use a JSON to retrieve the information and then store it in the database.
The information is going to be just text and some fields will contains links to images I want to then download (get to that later). Just wanted some advice on best practices. I have done some searches on SO and other sites but can't find much advice. Also as a side note any examples you know of that are good for noobs :)
Based on what you write here I would pick JSON.
To core points:
JSON is a standard format.
Android ships with a JSON lib (org.json) making it easy to handle it (encode / decode data).
JSON is known by a large community so you can ask questions and get them answered rather easily. With a custom format you cannot tag the question as 'json' here at SO... ;-)
Using standard formats and libraries helps you to avoid designing and implementing this stuff yourself, which makes your software more robust.
Sometime later you might need to add more complex data to your project. By that time it will be rather straightforward to use JSON's array and objects. With your private scheme you will have to add this capability to it and extend your parsing code. That can easily introduce subtle bugs. Or you might decide at that point that it is too hard with your custom format and decide to move over to a standard like JSON, XML, etc. At that time it costs you much more to shift over than if you start with a standard format. Consider time invested to write and test the current code and then the extra time to change to the standard format for the current system.
Related
I have one file which is create in iPhone using serialization object. and i want to do read in android. Is it possible or not? please reply fast in advance thanks
I am assuming that the serialized data is in a pList.
See this http://code.google.com/p/plist/
You should be able to read any file generated by another language. It's better if there's a library out there for it. It'll get complicated if the file uses arrays, especially dynamic ones. This may require some fun time with a hex editor. I can't guarantee reliability with this method though if the data isn't simple. Just realize that this may end up being a tricky task
It's better to have a file spec made. You don't have to use a binary file, as you can use something like JSON or XML if it's all text-based information.
Many times my client ask me whether they will deliver data via XML feed or JSON strings. I usually say:
XML if you already have a feed and do not have a web developer who will create script for generating JSON strings
JSON if you do not have any feed and need to create any from the scratch
What do you say? Do you think that delivering data via XML feeds is obsolete and that XML is over-complicated and too heavy?
Should I advise all clients (for the sake of the future) to move onto JSON way of delivering data?
EDIT
From another discussion https://stackoverflow.com/questions/2636245/choosing-between-json-and-xml I can see that JSON is advised for web services, which is the most used case scenario in my clients. It seems that I was advising them properly.
What is they want to pass news articles onto a mobile device - shall I advise XML of JSON?
What about post&get cases when I need to post some data and the to get the response which will be displayed on user's mobile device - XML or JSON?
If the consumers are browsers or mobile devices, I would recommend JSON.
Faster
Lighter
Native parsing support
If the consumers are other programs, I would recommend XML
Can be validated easily
Code generators available to make programming easy and is less error-prone
JSON - if you have a choice :) Google GSON is a serious help there.
We Use JSON: If we want to serialize a data structure that’s not too text-heavy and all you want is for the receiver to get the same data structure with minimal effort
We use XML:If we want to provide general-purpose data that the receiver might want to do unforeseen weird and crazy things with, or if you want to be really paranoid and picky about i18n, or if what you’re sending is more like a document than a struct, or if the order of the data matters, or if the data is potentially long-lived.
This discussed topic might help you .
I agree with all the other recommendations for JSON, but for me the main reason for going with JSON is it's far easier to process on the server especially if you are using a language that supports the JSON structure natively (e.g NodeJS or Python).
I would not say XML is obsolete though. The one obvious case where XML wins is readability. As a programmer I would say JSON is just as readable but I've worked with a lot of people (mainly web designer types) who prefer the look and feel of XML, probably because they are already intimately familiar with HTML.
I agree with your assessment really. Json is easier (for a human) to read, more intuitive and lightweight. XML is better if you have lots of existing XML solutions/interfaces that you're plugging in to. I see XML as the established, mature heavyweight of structured documents, but you don't always need an established, mature heavyweight. It all depends on the use case.
I am a php/mysql developer learning android. I am creating an android app that receives info from my php app to create list views of different products which will open a web view of that product's detail.
Currently my php cms web application outputs xml lists for an iphone app.... (also, separately outputs html). I have full control of the php app so if there is a better way to output the data for the android app please let me know.
I have created code that reads the xml from the web and creates the list view. The list can be refreshed daily, so the data does not need to be read from the online xml every time the app starts.
So I was thinking to store the data retrieved locally to improve my apps responsiveness. there may be up to 500 product descriptions to be stored at any given time in up to 30 different xml lists. I am starting development with one xml list with about 30 products.
For best performance should i store the product info in a sqlLite db or should i store the actual xml file in the cache/db or some other method like application cache.
I also was think to create the update of the data as a service, would this be a good idea?
The most efficient way to store data is RAM. But if you want to cache it, then the most efficient way is Database.
I recommend you store your data in sqlite android database.
You could also consider zipping you xml for faster network transfer and unzipping through java.util.zip package classes. You could even consider a simpler format for transmitting data, less verbose than xml, using a datainput/outputstream.
(I do that in of my apps and it works great)
Here are some details on data input / output stream method :
imagine a proprietary protocol for your data, only what you need. No tags, no attributes, just raw values in order.
on the client side, get an input stream on your data using URL.getContent() and cast it in input stream.
on the client side still, build a data input stream encapsulating your socket input stream and read data in order. Use readInt, readDouble, readUTF, and so on.
on the client side, from php, you need to find a way to save your data in a format that is compatible with the data format expected by the client. I can't tell much about PHP, I only program using java.
The advantage of this technique is that you save bandwith as there is only data and no verbose decoration due to xml. You should read about java specs to understand how double, int, strings are written in data output stream. But it can be hard using two languages to get the data right.
If php can't save format in a suitable way, use xml, it will be much simpler. First try with just plain xml, then give a try using a zip or tarball or xml file.
But all this is about speed gain during network connection.
The second part of what you have to do is to store each row of your list in a SQL table. Then you can retrieve it pretty fast using a CursorAdapter for your list view (it breaks the charming MVC model but it is quite fast !).
Sorry about this, but it became too long to write as a comment. This is not intended to be an answer to your question, because in my opinion Stéphane answered very well. The best solution is indeed to store the data in an sqlite database. Then you need to create the class to be used as a connection between the data, the database and the app. I don't want to take credit for what is said here already (I, too, voted it up).
I'm concerned with the other suggestion (use of low level raw streams for data manipulation, the list steps on that answer). I strongly recommend you to avoid creating your own proprietary protocol. It goes like this:
I need to exchange data.
I don't want to deal with the hassle of integrating external APIs into my code.
I know I can write two 5 minute routines to read and write the data back and forth.
Therefore, I just created my own proprietary format for exchanging data!
It makes me cry whenever I need to deal with unknown, obscure and arbitrary sequence of data blobs. It's always good to remember why we should not use unknown formats:
Reinventing the wheel is counter-productive. It seems not, but on the middle term it is. You can adapt your project to other mediums (server-side, other platforms) easily.
Using off-the-shelf components help you scale your code later.
Whenever you need to adapt your solution to other technologies and mediums, you'll work faster. Otherwise, you would probably end up with ad hoc code solutions that are not (easily) extensible and interoperable.
Using off the shelf components enables you to leverage advances in that particular technology. That's particularly important when you are using Android APIs, as they are frequently optimized for performance later down the road (See Android's Designing for Performance). Rolling your own standards may result in a performance penalty.
Unless you document your protocol, it's extremely easy to forget the protocol you created yourself. Just give it enough time and it will happen: you'll need to relearn/remember. If you document, then you are just wasting the computational time of your brain.
You think you don't need to scale your work, but chances are you will most of the time.
When you do, you will wish you had learned how to easily and seamlessly integrate well known formats.
The learning curve is needed anyway. In my experience, when you learn, you actually integrate well known formats faster than imagining your own way of doing things.
Finally, trust your data to geniuses that take their lives into creating cohesive and intelligent standards. They know it better!
Finally, if the purpose is to avoid the typical verbosity of XML, for whatever reasons, you have several options. Right now I can think of CSV, but I'm no expert in data storage, so if you're not confortable with it, I'm sure you can find good alternatives with plenty of ready to use APIs.
Good luck!
I was brainstorming how I should handle this. This is how the application is going to work:
User enters multiple pieces of data into app
App stores data into SQLite database
User hits SYNC button and app will pass all new/updated/deleted info to site PHP and update MYSQL.
I was thinking I can do a loop where it sends (and receive) one row at a time to mysql or I can use a string builder to build a XML, and pass (and receive) the XML string to PHP to process. The xml will have tag data specifying if the element is to be added, deleted or updated.
I figure the XML is a better option, but I'm coming here for opinions how I should push multiple rows to be added/deleted or updated to my MYSQL because I feel there's probably a more efficient/easier way of doing this.
Thanks!
--UPDATE--
Here's some helpful links I found of JSONArrays for those seeking similar information as I am about Android SQLite to PHP MYSQL.
Nice tutorial about JSONArrays in PHP: http://webhole.net/2009/08/31/how-to-read-json-data-with-php/
Another tutorial about JSONArrays in Java: http://www.androidcompetencycenter.com/2009/10/json-parsing-in-android/
Ah, opinions. Painful things though: everyone has one and everyone thinks their opinion is better than the next persons'.
I've implemented a system that is pretty much identical: I used JSON for it though. There is no intrinsic issue with using XML: whatever translation layer you are comfortable with is probably fine. JSON was (for me) a bit more compact than XML, required less code on both sides (json_decode is your friend) and seemed to me to be an easier row to hoe than using XML. However PHP's simplexml would probably work fine as well.
If you're doing this from scratch you might want to look at one of the systems with automatic data syncing like Mobile Couchbase (see http://www.couchbase.com/products-and-services/mobile-couchbase): would require a fair bit more tooling and a bigger server/client resource footprint but might get you there faster.
I want to store structure type data (i.e. information of call logs like name, number, type of number, date, time, duration). Which is the best way and which is faster? SQLiteDatabase (make table and insert, delete logs in it) or use file storage (means make one class for all parameters and write their objects in file using input/output Stream and serializable) or the another way i heard about it is XML parser but i don't know this.
Please help me. Thanks in advance.
It depends on what you are trying to do.
If your goal is speed, the SQLite will give you a serious run for your money (especially if you wrap multiple inserts into transactions). SQLite has been optimized for everything you mentioned and it would be very easy to leverage the speed it can give you.
If portability is your goal, then files may be a slight bit easier. Files can be moved back and forth very easily easily, whereas SQLite might take some more effort.
If being able to search is your goal, then you'd be a fool not to use SQLite, as it is extremely good at searching and filtering results.
I can't give a very informed answer here because I'm just as new to the subject as you are, but here is the link from the developers page that goes over the different types of data storage. I hope you find it useful. http://developer.android.com/guide/topics/data/data-storage.html
Personally, given you know the basics of Databases I would use a sqlite database. It's pretty straight forward in Android. In terms of speed I don't know which is faster, but if you don't have millions of datasets it won't matter.
In my experience in most cases JSON in a file is enough (mostly you need to store an array or an object or just a single number or string). I rarely need SQLite (which needs more time for setting it up and using it).