Develop Reference

Asking for advice of how to appraoch an application

as part of a university project, i have to build an android app that will contain informations about diseases, the diseases will be listed in a list (alphabetic order), when clicked on a disease you'll be directed to another layout that contains informations about the disease chosen (including text and images).
i'm new to this and i don't know how to approach this app..and for the text should i build a database or directly input the text inside the app or something like that .if you know a tutorial or something that would help please share
Ps: there is almost 60 Diseases and each disease will have a subitems (causes, treatment, clinical signs .)
thanks

First of all, the comments are right. Please be more precise in your question. Ask what specific problem occured, if possible provide code samples, errors and research state. https://stackoverflow.com/questions/how-to-ask
UI Design (List)
there is almost 60 Diseases and each disease will have a subitems
Therefore I would suggest an ExpandableListView.
Check out this code sample: https://www.journaldev.com/9942/android-expandablelistview-example-tutorial
Afterwards if the user clicks on an item, you open another Activity with details
Data Storage
should i build a database or directly input the text inside the app or
something like that
Static approach
As you can think of, putting data directly into views makes it difficult to maintain, but is faster implemented and less difficult.
Implemenation: I would suggest putting the data into res/raw as a .json file. In your code, build a JSONObject out of it and pass it to the ListViewAdapter.
Dynamic approach
You need Internet permission, a webserver and a remote database from where you can query the data.
Implementation: If you have a hosted webserver you probably have PHP and MySQL databases. Create a table, fill it with data and build an API in PHP where you provide the data from the database. If you have a VPS or dedicated server you can use MongoDB which works with JSON out of the box.
My guess
For an university project, use static. Otherwise dynamic of course.
Hope this helps

Design choice for Android app

I am new to Android (but proficient in programming) and I have been reading the Google documentation.
I am trying to build a small app, just to get familiar with Android (not a very fancy app, just for learning app dev).
The app would have an initial activity containing a list of items, and the user can view them (through another activity), edit them (again another activity) or create new ones (again another activity). My concern is how to store this list of items in the phone.
I do not intend (at the moment) for the app to be synced with any external service, so I am happy to store all the data in a file. Typically I would be looking at 200 items of small size, so a text file (maybe XML or JSON) would be enough I think (SQL would probably be overkill here).
My question is: if I have an XML file with all the items, do I need to parse it and load it in memory for every activity?
For example:
the user enters the app to see the list of items -> must load the XML
the user wants to add a new item-> I need to load the XML again to be able to add an XML child
Is this the most natural way of doing this in Android? having to load the same resource over and over in each activity?
Thanks

If you want to reuse files you may use adapter. You can either create custom adapter or use default one. Besides that you may know programming concepts such as Design Patterns. My point is to reuse in android can be done programmatically.
In your for storing data would be better to use SharedPreferences here tutorial to understand idea about it

If you don't want to use SQL to store your data, you can try SharedPreference.
And yes, you have to load all values in everytime you read or write. But don't worry, it won't be hard for mobile phone hardware.

What's the best way to choose program database in android

I want to copy a premaded database in user's device. then use it in the android App.
but I don't know where is the best place for that. (a place that I can copy file to it)
for example:
I have a database named "FoodsDB.db" in assets folder
When application starts for first time, it copies the DB from assets to user's Device
Then in DatabaseHelper address it and use it

Right off the bat without knowing exactly your code I'd try and guess that when you say "I don't want to submit changes" means you shouldn't invoke SaveChanges(). Shouldn't you try to completely discard the entities, then? I doubt it's that simple, but I post this nonetheless.

After you've added the example code I can see it's different then I thought. You won't be able to use a rollback (see unit of work pattern). What you need here is a PARTIAL undo, which is different then the full-scale undo I initially proposed by throwing away the entire context.
Look here for an excellent solution to your problem:
Entity Framework .Remove() vs. .DeleteObject()

Is there any way to extract queries from SQLite?

I'm trying to create some sort of backup & restore function in my app. Before that, I've been reading for a while to understand if it's possible to achieve, but I found out this question:
Sqlite DB Android Backup/Restore
The only other way I could see to do it, would be to read the actual contents of the DB and generate a file containing the SQL which which it can be restored from, this is obviously a more complex and doesn't offer any advantages to justify this complexity.
This answer, I think, is the best way to accomplish that; not explorting the .db file, but exporting queries.
You know; when you export a SQL data from mysql, you get a file which contains all the queries that creates the structure and queries that fill the structure with data.
That's what I'm trying to mimic; generate a file which contains sql queries from a .db file.
Do you guys think it's possible, I mean, is there any builtin method to achieve that?
Otherwise, if its too hard to handle, how do you manage to avoid what this user (https://stackoverflow.com/a/10842043/1943607) is talking about?
So, I disabled WAL with "PRAGMA journal_mode = DELETE" and then I was able to view the database in the browser and able to restore it on my test device fine.
That previous part, I can't understand it. Is this a configuration you set to sqlite?
Thanks

I haven't actually tried this with sqlite, but with mysql you could do things like create "dumps" of your database. Those dumps contained exactly what you describe: a set of queries that, when executed together, recreate the database, including the contents.
Judging from the "sqlite3" documentation found at http://www.sqlite.org/sqlite.html (especially the "Converting An Entire Database To An ASCII Text File" section), you can do the same for sqlite. Since you can execute shell commands from a java application (using Runtime.getRuntime().exec() methods), and you are the "owner" (Linux user id) of the database, you should be able to run this "sqlite3 .dump" command even on a non-rooted device. I have never seen an Android device without the sqlite3 tool installed, so the command should always be available.
Moreover, since dump file is just a text file, you should be able to prepend any PRAGMA's to it that are required for compatibility (like the one you quoted).
I haven't tested any of this, but just wanted to think with you on this interesting topic.

An sqlite database is just a file so you could copy the file but I think you may have problems with permissions in android preventing you from accessing the database.
A better solution IMO would be to sync your data to an external website.
Using a combination of a custom sync adapter and the account manager with a website or web service that has a RESTfull api to receive and send the synced data would be the most reliable approach.
http://developer.android.com/training/id-auth/identify.html is a great introduction to setting up the account manager.
And for a custom sync adapter this is a great starting point.
http://www.c99.org/2010/01/23/writing-an-android-sync-provider-part-1/
and http://www.c99.org/2010/01/23/writing-an-android-sync-provider-part-2/
And finally an explanation of how it all fits together
https://sites.google.com/site/andsamples/concept-of-syncadapter-androidcontentabstractthreadedsyncadapter
The above approach would enable a user to switch phones and retain data at the same time and the data would always be up to date (providing you sync at the appropriate times.
It seems like a lot of work as you will need to set up a web service but it is the BEST way to make sure data is kept safe and secure and can be restored and backed up at any point.
For a web service there are lots of options available to you including cloud services such as Google docs or writing your own website. Ruby on Rails is a great solution for developing your own site as you get a full RESTfull api out of the box and it;'s dead easy to secure/lock down a rails site to authorised users only with a couple of lines of code and with Heroku you can get free hosting.
As usual with Android development the simplest of requirements actually ends up being the most difficult to implement but where data safety is paramount then it's worth the effort to do it properly.

The question is too open to answer simply because the changes that may apply to the db file content are open and one can't guarantee a specific behavior .
On the positive side sqlite project is an open source and the format of the DB file is specified Here
After taking a look there, it seems very possible/not too complicated to parse any DB file looking for Data Only and write it/dump it to another functional db file.
I believe this is the fastest and cleanest solution to the issue in hand.
so to wrap up:
Copy DB file everytime you want to back it up.
When you want to restore create a new DB using Android APIs.
Parse the data from the backed up file and write them to the newly created DB.
P.S:
regarding how to use
PRAGMA journal_mode = DELETE
Simply use db.exec("PRAGMA journal_mode = DELETE"); when creating the DB

Android Remote Database

I'm in the process of developing an Android application that will need to connect to a central database. Users should be able to access records and add records to the database through the application. The data itself will be fairly simple with each record being made up of a number of text fields.
The database will be developed specifically for the application and only needs to be accessed through the application. Initial reading seems to indicate that a web service should be written to parse data into xml format, for use by the app.
Seen as the database is being developed from scratch, specifically for this purpose, I would like to make sure I am heading in the right direction. I have very little experience with databases and would really just like a pointer on where to start reading. Any suggestions on the format the database should take would be greatly recieved too.
Thank you

You seem to have the idea down, if it were me, I would recomend using JSON instead of XML for the Webservice, they work in very similar ways, but JSON is a lot smaller and will make the application noticeably (as in it will make a diference for the user) faster. This is specially true if you are sending large amounts of data.
Take a look at this:
GSon

If your familiar with other aspects of Java, you could make the implementation entirely server side by means of JSPs. You could access the database via the phone's browser or any other browser. If you implemented a DAO factory on the server, this would enable you to switch databases from say Oracle, to MySQL etc by means of a properties file.