What is the best way to save several strings on android?
I thought that the best way was SQLite, but in this case when I close my app the data will be save? When I open the app again the data will be there? Or should I use txt files to save it and restore it?
It depends on what you are trying to do with the file. You have several options when you are saving data: internal storage, external storage, caching, SQLite database, or networking. If you are just saving a couple Strings I think that creating a database is overkill. I would look at saving the files to internal storage. You can write the Strings to a file then retrieve that file when you restart the app.
You don't want to make things more complicated than they need to be. Keep it simple. If you are saving a couple KB worth of data, use a file. If you are getting into MB worth of data, and need to query specific data sets, then look at a database. You have to remember that databases take a lot of time and resources, not only to set up, but to maintain.
Here is the Android document that outlines the different ways to save data to a device: http://developer.android.com/guide/topics/data/data-storage.html
This should really help you understand what is going to be best for you.
Related
I have started learning Android development and I have a very newbie question. I understand that Android can store data in SQLite for example, but what other approaches are there to the storage of data within your application?
Do Android apps ever have data 'embedded' within the application, in which case what sort of data structure or concept would this use?
I am thinking of a scenario where the data is static but is perhaps not a large enough dataset to warrant a database..e.g. an app with general knowledge questions and answers
Any guidance much appreciated
Rowan
Yes You are correct You can use SqLite Database for storage
other ways to store data is SharedPreferences
But in your case you wanrted to save questions and answers which is static one so you can create a text file and put that in your assets folder and you can read that file as any other text file in java
Refer this link how to read file from assets folder
1.Sqlite Database
2.Shared preferences
3.Internal memory
4.external memory i.e sd card
i would suggest you to go with Database. as it will let you store as much data as your app needed, There are some other option also present like
Sharedpreference i.e. cookies in general term. It let u store only few KB data and not good to store much data. When u retrieve data from cookies. All data will be store into ram and use app memory. that is use less when u do not need all data to retrieve and store into ram and then remove
Store into file and ship that file with your app. Yeah. this could be better idea again. you need to read it byte by byte. and hence reading to mid or last line will store all data into ram and hence will take memory.
Use Web Service to download data. It will let you store Large data and you have to download using Web APi. Hence it could be better idea. But this requires active Internet connection to play game to run app.
There must be some other option also present. You can search. surely you will find them :)
Overall Database it good solution for all app. As it will let you do search store delete and let you do other operation in less amount of memory. In Mobile Development Memory is very Important thing we have to take care of.
Let me know if you have other unclear thought.
item
You could also store info in a server.
Pros :
You can change the content without needing user-side update of the app.
Cons :
Your app (mostly the UI) would need to manage connection problems.
You may need to implement async tasks for querying data from server.
I'm currently developing an android app in which I'm dealing with php files that returns json, the json then gets parsed and is used to fill up an arraylist of different objects.
What I'm trying to do is, I want to cache these objects in case of no internet so I can reload them and make the application useable offline.
Currently I have 2 solutions for this:
A) Make an SQLite database and creare tables with the same structure as the objects I'm trying to cache and then reload them on startup
B) Save the JSON strings inside the shared prefs and parse them on startup.
I didn't really find any best practices or tutorials when I came across data caching so I'm lost now and I have no idea what to do. So if you guys can please help out I'd be thankful.
You might find the following talk interesting:
https://www.youtube.com/watch?v=xHXn3Kg2IQE
As you can see, a lot of scaffolding goes into the ContentProvider approach. For a very simple app, it can be acceptable to just cache some JSON in a SharedPreferences. However, as your app becomes more complex, the advantages of the ContentProvider will be worth it.
You can use files instead of sqlite and shared preferences.
Shared prefrences is using for small data.
Sqlite is using when you need to make queries on stored data.
So I think it's better to cache in files, or if you are using something like retrofit or any network lib you can check if they support caching and use it.
Definitely not option B. Shares preferences are not suitable for storing large amounts of data. It's XML so cannot be queried like Sqlite. The time to retrieve a single item will increase linearly with the amount of data stored. Secondly JSON will have special character these will need to be escaped which means the storage size will increase even more.
There is however an option C. Using cache files. This approach and other store options available to you are described in the google developer guide and this is essential reading.
So in summary: you options are to parse the JSON and store it in sqlite or to save the json as a file in the cache directory.
I have read through the Android Storage Options and I have a question that I haven't been able to find the answer to:
Should I use SQLite to store my data or should I use a JSON object that is written to a file?
Requirements:
Store (up to) a few hundred instances of the same object. Each instance will be somewhat complex, storing reference to images, smaller objects, etc. The data will be stored locally, with the option of cloud backup. All the data will be loaded on startup and saved when manipulated by the user.
The reason I ask this is because I don't have a lot of data to store - for a SQLite database there will probably never be more than a few 100 rows, which makes me think SQL is overkill.
Also, exporting my data to a JSON file will allow me to easily import/export from different device platforms (I already do this on iOS).
Or, maybe there's a better option? If there was an NSCoding type library for Android I would probably use that.
Any opinions are helpful.
Thanks!
From the presented so far, storing in files will be more advantageous.
Considering that each "unit" is less than 16 attributes, a json file with short identifiers will likely generate a larger file representation than the SQL representation equivalent.
However, the local file manipulation will allow for easier interactions, as well as easier backing up/down.
Also, the File class is simple enough to generate less issues when compared to SQL.
Finally, given the choices, you are going to have to evaluate the operations used.
If you are going to compare the data, then SQL is likely to go faster, but if you are just inputting/outputting each data as a separate object, than files are going to be as fast as SQL.
Finally, please, particionate your objects, do not create just 1 file with all the info.
I have read through the Android Storage Options and I have a question
that I haven't been able to find the answer to:
Should I use SQLite to store my data or should I use a JSON object
that is written to a file?
You need to analyse your requirement again.
maybe there's a better option?
It depends upon your requirement.
if Your requirement is fixed to simply storing and retrieving then you can have a look on tinnyDB, which is basically using the SharedPreferences as storage mechanism. But if you need case base based selection/query of data then you should go with SQLite.
I am trying to build a application which will be a Ebook kind of (Lot of theory & diagrams) will be there.
Now what i want to know is that since there are many ways of storing the data which one will be the best
Storing in Database
XML
Or simple text files
I am very concerned about the security of the data as well. Since this will be a paid app, i want the data to be secured and also be fast and convenient.
Also, I thought of converting the doc files (Data) in to epub format & then use epub api's to access the data and show it on the android app screen, will this be a gud idea to go for? as compared to the above ways?
Which one will be more secure, fast, flexible & easy!
It depends on how you will access to this data. If you will store in xml you will must to read the whole file from the start to access to chapter (or load to memory, for example). It's not good idea if you will store big data.
Storing in SQL faster. You can gain access to any chapter. You don't need to read all data, like in xml.
Simple text file has the same problem like XML (xml is textfile).
The only one way to secure you data - encrypt it. If user will get root on their device, he will gain access to your files and databases. There is no meaning where you will store your data.
Depends on what is more important to you - speed or security.
Speed
Definitely SQLite, it isn't exactly the cleanest, but definitely the fastest way.
Security
Custom files which are encrypted - it will take a while to read the whole file and then decrypt it in order to display it, but you can be sure that the attacker will access the files encrypted and without the knowledge of the encryption - those data would be useless to him.
EPUB
If you're concerned about security then don't, unless you know how to apply DRM...and that is not a way to go honestly.
I think that the best way to store big amount of data is database. In Android it is sqlite database. I recommend you to put all your text data into sqlite database. You can structure it in easy and beautiful way. Then put your images into assets folder and store the pathes to the the images in database.
Advantages of database solution:
Always well structured data
Easy way to update data with version control system.
You can store and get fast accesses to really big amount of data.
You can use encryption to protect your data.
Disadvantages
It is more complicate to write good code for database solution then for XML or JSON one.
P.S If you will decide to use XML I recommend you to change it to JSON. It is faster and easier to use.
Which one will be more secure, fast, flexible & easy!
Secure: It mainly depends on encryption system.
Fast: SQLite, you can read some advantages of SQLite here Android Performance : Flat file vs SQLite
Flexible and easy: Storing the encrypted files in internal storage is a flexible and easy way. I think it is secure enough. Here you can get some android security tips about storing data http://developer.android.com/training/articles/security-tips.html#StoringData
for saving little data you can use xml for strings but you lose fast loading factor
sqlite is good for almost every purpose, but Security
My app collects data which it stores in arrays, and I need to be able to access the data from outside the app. The tablet I am using has no SD card, so I'm thinking the best way to transfer data would be to save to 'external' system memory. I have found tutorials to save data on internal storage and for specific data types like pictures onto SD cards, but I can't figure out how to write an arbitrary file to an arbitrary location. Thanks.
This sounds like a perfect time to use a SQLite database. Android comes with SQLite support built in so its easy to set up. You can just create a database and store your array data there (you can even store pictures too as a byte[]). There are a number of tutorials that show how to do this. Here is 1 and 2. It should be pretty easy from there.
I'm not sure that you can write to an arbitrary place on the Android system. You could write to a file in /data/data// and then email that file to yourself.